Ignition
Solutions for Small Engines and Garden Pulling Tractors
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- General information - Updated 5/14/09. (Click Refresh.)
- Setting the [point] ignition timing on virtually any small gas engine.
- Setting the [point] ignition timing on older Tecumseh engines.
- Crank Trigger Electronic Ignition Section. (Updated 5/26/09)
- Using crank trigger ignition on a cast iron block Briggs & Stratton or Tecumseh engine. (Rewritten 12/22/06)
- Fabricating a fool-proof killswitch for a garden pulling tractor.
- Cub Cadet Factory Wiring Diagrams (http://www.cubfaq.com/wiringdiagrams.html)
- Using an Electronic Ignition Distributor in an Older Automotive Type of Engine. (Rewritten 12/26/06)
- To search for a word or phrase in this Web page, with Microsoft Internet Explorer 6.x, press CTRL+F to open the Find dialog box.
Spark-ignited engines require a spark to initiate burning of the air-fuel mixture in the combustion chamber. The spark in each cylinder is provided by a spark plug and is actually a flow of electrical current through the air and fuel vapor between the closely spaced electrodes of the spark plug. The resistance of air is very high. Therefore, a 15,000- to 30,000-volt potential across the gap is used to fire the plug. Typically, the ignition system must supply this high voltage from a 12 volt power source, such as a storage battery. Moreover, the spark must begin at the proper point in the cycle and must be of sufficient duration.
Whenever a manufacturer wants to sell their latest fancy ignition system, they run a test that shows that their unit puts out more voltage than the other guy's. If you read enough ads with claims of extremely high available voltage, you may begin to think that voltage is the only thing necessary to make your ignition the best in the world. After all, if ignition "A" puts out more voltage than ignition "B", the one you would want is "A", right? Sorry, but that isn't necessarily so. Ignition "A" may put out more voltage, but is it more mechanically dependable than ignition "B"? Did you know that 90% of ignition failures are mechanical, and not electrical? Blame burnt or dirty points, faulty condenser, bad switch(es), broken or chaffed wires, loose screws or connectors, slipped timing, etc. By the way - whenever a condenser goes bad, the engine will either: 1. Not start. 2. Start and idle fine, but when the speed increases, it'll run very erratic.
The importance of extremely high secondary voltage for more performance has been somewhat overplayed. An ignition system, regardless of type, produces only enough voltage necessary to jump the spark plug gap and ignite the air/fuel mixture. In perfect condition, a good spark plug wire and spark plug with a gap of .035" can't handle much more than 32,000 volts. If an ignition could produce more than that, then the extra voltage would escape through a leaking spark plug wire, a small crack in the coil, etc. Besides, an average engine simply just doesn't need that much voltage. In most cases, you don't need a high performance coil. If a plug requires only 10,000 volts to jump its gap, then a "Super Coil" that's advertised to produce 40,000 volts will produce just 10,000 volts for that same plug under the same conditions. An ignition advertised to produce 40,000 volts may have the potential to do it, but unless everything is in excellent condition, only a fraction of that voltage would reach the spark plug.
As a spark plug's electrodes wear, its gap increases, so more voltage is required from the ignition coil before the spark is able to jump across the gap. If uncorrected, the gap eventually increases to the point where the plug requires more voltage than the coil can produce. However, a high performance coil would probably be able to to fire the worn plug. Did you know that most stock ignition coils will produce enough voltage to jump a gap of up to 3/4 of an inch? Of course, no spark plug electrode will ever wear that wide. Therefore, the use of a high performance coil really isn't necessary, except in extreme high compression engines.
In most cases, if an engine is kept in perfect tune, the factory stock ignition system provides more than enough voltage for the average garden pulling tractor. Most conventional stock ignitions are designed to provide a hot spark up to a relatively low engine speed. With Kohler engines running in modified form, they will get up as high as 9,000 rpm. But at higher rpm with the points system, the points open and close so quickly that the coil's primary winding has less time to absorb voltage. This means the condenser doesn't have enough time to rebuild the capacitance discharge. As a result, with the stock system, secondary voltage to the plug decreases and the engine won't run at its full potential or it may sputter just when victory is in sight. However, for most garden pulling tractors, a stock ignition system that's in good condition will provide plenty of spark.
There are 3, well, actually 4, types ignition systems that's used on all small gas engines, despite if it's a 2- or 4-cycle engine:
- Magneto ignition
- Battery ignition
- Breakerless ignition
- Crank trigger ignition
-
The magneto ignition system has breaker points, a condenser and an ignition
coil that generates it's own electrical power to produce the spark every
time a magnet in the flywheel passes it. Magneto ignition coils can't be
used for a battery ignition system because they must produce their own electrical
power to create the spark. The ignition timing for the magneto ignition is
the same as for the battery ignition. It's set or adjusted by widening or
narrowing the gap of the breaker points. This advances or retards the ignition
timing. Use a test light (with the engine not running) or an automotive inductive
timing light (with the engine running) to set the ignition timing on a magneto
system, but a battery must be available to power the test light or timing
light. Magneto ignition is very popular on virtually all lawn mowers, garden
tillers, riding mowers, lawn tractors, and lawn & garden tractor engines.
- Most air-cooled, cast iron block small gas engines with a magneto ignition system with points can be easily converted to battery ignition. All that's needed is a condenser that's designed for battery ignition (automotive or Kohler), a 12 volt early style canister-type ignition coil (automotive or Kohler) a ballast resistor if the coil requires one, a spark plug wire (with terminals and boots), and a 12 volt battery. The same ignition points and spark plug can be used. And with battery ignition, the engine will need a charging system to keep the battery fully charged so the ignition will produce a hot spark. When converting to battery ignition, remove or disconnect the old magneto coil and condenser first.
- If need a kit to convert your engine to battery ignition, please contact me if you're interested.
- The reason battery ignition can't be used on the smaller aluminum block Briggs & Stratton engines is because the [B&S] condenser is part of the ignition points. For battery ignition to work, one half of the point contacts must be connected to the [battery] condenser and negative post on the ignition coil, and the other half must be grounded. Therefore, if the point contacts are separate from the condenser, it'll work. Or better yet, install B&S's Magnetron electronic ignition.
- The battery ignition system uses breaker points, but a different type of condenser than magneto ignition, and an ignition coil that requires an outside electrical power source (battery) to produce the spark. Battery ignition is used on most older garden tractors, farm tractors and virtually all older (pre-1974) automobiles.
- The breakerless or solid state ignition system operates on the same general principle as the magneto system but does not use breaker points to time the spark and a conventional condenser. Instead, a trigger module containing solid state electronics performs the same function as the breaker points. Because there are no breaker points in this system, there are no requirements for ignition timing (on a small engine). Solid state ignition is self-energizing. Therefore, it does not require a battery or an outside electrical source. Breakerless ignition is pretty much maintenance free, with very few parts to wear out or go bad. Breakerless ignition is used on virtually all small engines built from 1982, and virtually all large engines (farm tractors and automobiles) that's built from the mid-1970s.
- The crank trigger electronic ignition system is a combination of the breakerless and battery ignition because it has no breaker points or condenser but requires an electrical power source (battery) to power the ignition coil and control module.
Testing the Strength of an Ignition System -
When testing
the strength of an ignition system, it can be tested at the spark plug;s
tip. Or better yet, it's best use a universal spark tester like the ones
pictured to the right. But when testing the strength of the spark with the
just the spark plug, always use a new spark plug, and the ignition must be
strong enough to produce an audible "snappy" and visible bright
blue spark at the plug's tip. A good spark
plug is supposed to produce a blue, audible
snapping sound with it placed somewhere on the engine when the engine is
cranked. (The "snapping" sound is the result of electricity breaking the
sound barrier.) If the spark is visibly white or
red in color, either the [used] spark
plug is fouled or the ignition coil is weak and needs replacing. Unlike gasoline,
alcohol fuels (ethanol and methanol) will rarely foul spark plugs.
Engines with a magneto ignition system must be cranked over at a good speed to produce a strong spark. But on engines with battery ignition, there's no need to crank the engine to test the spark. What can be done is momentarily and lightly ground the points with a small metal object, such as the tip of a screwdriver.
And try to avoid using a low cost, inferior quality or "cheapie" spark plug, especially with the wording "LAWNMOWER" printed on them! I never had one of these last more than 5 minutes in any engine. Acquire a Champion, Autolite, AC or major name brand spark plug, or what the engine manufacturer suggests.
Also, if the spark plug's tip is black or has wet gas on it, and if you think the problem is in the carburetor, well, the carburetor must be working fine because the engine is obviously getting gas. As an older experienced mechanic once told me, "Most carburetor problems are electrical." This has proven true more times than I can remember.
Information about Ignition Coils -
Some
ignition coils require an external ballast resistor (off any 1955-57 GM vehicle)
or a full-length resistance ignition wire (off any 1958-74 GM vehicle) to
prevent from putting too much voltage through the primary circuit and ignition
points, which could burn them up. A ballast resistor or resistance wire is
basically a voltage reducer that reduces 12 volts down to anywhere between
6-9 volts, depending on the load. (The ballast resistor shown here is the
same used on the 1955-57 GM vehicles.) But if a coil reads "12 VOLTS" on
its casing, then it has a built-in resistor. A resistor may not be needed
with many new coils because most of them nowadays have a built-in resistor.
And using a resistor doesn't effect the voltage output of a coil. It only
prevents from burning it up, and it saves wear on the ignition points. The
reason manufacturers don't install a resistor inside some high performance
coils is because these coils draw more amps from the battery. This causes
the resistor to operate at a higher temperature, which could overheat and
damage the windings within the coil. If you prefer to use a high performance
coil, when you purchase one, be sure to ask the salesperson if it has a built-in
resistor or if it requires an external one. This is important for the life
of the coil.
With battery ignition, most high performance ignition coils requires two condensers [connected to the ignition points] for quicker saturation at higher rpms but the points won't last as long because of the increased amperage that the coil draws. And a high performance coil has no effect whatsoever with crank trigger ignition when using a Chrysler or Ford ignition control module. And most stock coils produce more than enough voltage for even the hottest high performance engines built, especially when used with the crank trigger ignition.
Why Do Some Ignition Coil(s) Keep Going Bad?
There are three things that makes a quality ignition coil go bad. They are:
- Lack of a ballast resistor before the coil. (If the coil requires one.)
- Bad voltage regulator or rectifier. If the charging system continues to charge with no "falling back" reading on the amp gauge, this will put too much voltage through the coil, eventually burning it up. It could also burn out light bulbs, electrical accessories and burn up a good battery.
-
If a garden tractor is equipped with an automotive battery,
it could have a dead cell or all the cells are weak. (Bad or defective battery.)
Unlike in an automobile, a weak automotive battery will have more than enough
strength (cranking amps) to crank over a single or two cylinder engine with
no problems, and the drop in amperage (cranking power) wouldn't be that
noticeable. An auto battery with a dead cell or weak cells will cause the
charging system to continuously try to recharge it, but instead of the battery
taking the charge, it'll put too much voltage through the coil for long periods
of time, causing it to burn up. This too could burn out light bulbs and
electrical accessories. Test the battery's acid condition with a hydrometer
battery tester (glass tube with floating balls [pocket size] or a floating
bulb [full size]; which are available at virtually any auto parts store).
Don't trust a battery load tester. They only show if a battery has enough
strength to crank over an engine.
How To Test A Coil's Output Voltage -
The way I test a coil is I connect it in a circuit, like it's on an engine and then I check the width of the gap of the spark. If it produces spark at least 3/4", then it's a good coil.
When testing a ballast resistor for voltage drop, it won't show any resistance unless there's a functioning load on it with electrical current going through it, such as the ignition coil and/or control module with the engine running.
All
conventional point-type ignition systems that's installed in automobiles
and garden tractor engines utilizes a standard output (20,000 volts) coil.
And all automotive electronic ignition systems utilize a high output (60,000
volts) coil. You can identify the difference in these coils by the height
of the center tower. The high output one has a taller tower, to keep the
spark from shorting to the terminals.
So if you want more spark, instead of using a high dollar, aftermarket high performance coil, you could just use an automotive one that's designed for an automobile that has electronic ignition. (Early Chrysler and Ford products.) They produce about 60,000 volts.
On any ignition system, the voltage of the coil is the same at any rpm. The only way a coil will produce more voltage is when the spark plug gets weak or the gap on the spark plug is widened. The coil will produce less pulses of voltage at idle speeds and more pulses at higher rpms. But the amount of voltage will stay the same.
If you've ever experienced the metal strap on your ignition
coil of breaking due to normal engine vibration and because the metal itself
is too thin, then what you need to do is install two straps as shown in the
picture to the right. This would double the clapping grip and lessen the
chances of either strap of ever breaking again.
Ever had a good run going down the track and all of a sudden your engine dies, and then you found it was because of a faulty ignition coil? Well, chances are it wasn't designed for use on a garden pulling tractor. Even new coils have been known to fail in a very short time. The reason some coils fail is due to normal single cylinder engine vibration. The tiny wires (or windings) inside an oil filled coil will vibrate and break over time. Even the insulation on the windings themselves will "rub" or scrape against the other internal wires, resulting in a short. That's why it's best to use an epoxy filled coil to prevent the windings from vibrating, shorting out and/or breaking. The epoxy holds the wires solid, resulting in no vibration of the windings whatsoever. So for the little difference in price, accept no substitutes! Epoxy filled coils are the most reliable for use a garden pulling tractor. OEM Kohler coil part number is: #231281. A suitable replacement is part number 7-01643 from NAPA. You can also use a Borg Warner oil-filled coil (part # BWD E40P) that requires an external resistor. Or you can use a Borg Warner epoxy-filled coil (part # BWD E81) with an internal resistor. JEG'S (http://www.jegs.com), Summit Racing (http://www.summitracing.com), J.C. Whitney, Inc. (http://www.jcwhitney.com) and other sources also offers automotive epoxy filled ignition coils.
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| If you need any of the items listed below, please contact
me, Brian Miller, at: A-1 Miller's Small Engine &
Specialty Shop (1501 West Old Plank Rd., Columbia, Missouri. 65203 |
Phone: 1-573-875-4033). Please call any day between 12 noon and 8:00 p.m.
Central time, and please be patient because I stutter. Fax: 1-573-449-7347.
You can also contact me through Yahoo! Messenger:
Points and Condensers (Don't be leery of the low prices. These are new, high quality parts.) - |
|
 Ignition points for Kohler
4hp-20hp K-series single cylinder and twin cylinder flathead cast iron block
engines. Replaces Kohler # 47-150-01, 47-150-03, 47-150-03-S; Tecumseh #
32011, 32011A. $10.00 each, plus shipping. Note: includes angle
mounting bracket. |
 Condenser for Kohler K-series
and twin cylinder flathead cast iron block and other engines with BATTERY
ignition. Replaces Kohler # 230722, 230722-S. Can be substituted for
the Chevy condenser with no problems. Wire length: approximately 4-1/2".
$6.00 each, plus shipping. |
 Points pushrod for 10hp-16hp
Kohler K-series flathead cast iron block engines. Made of steel. OEM Kohler
part. Replaces Kohler # 47-411-04S. $10.00 each, plus shipping.
 Condenser for Kohler K-series
flathead cast iron block engines with point-type magneto ignition. Replaces
Kohler # 47-147-01S. $6.00 each, plus shipping. OEM Kohler part. Made
in USA  . Body length: 33 mm,
width: 17 mm. |
 Complete Ignition Tune-Up
Kit for Kohler K-series 7hp-16hp and twin cylinder flathead cast iron block
engines. Includes: points, battery condenser, points pushrod, spark plug
and points cover gasket.
|
 Chevrolet (GM)
V8 adjustable ignition points that can be used on the Kohler K-series 10hp-16hp
and twin cylinder flathead cast iron block engines. $3.50 each, plus
shipping. For competitive pulling purposes only! Has a stiff spring for
quick response at high rpms. Note: the "Chevrolet" points and condenser are
actually made for the 1957-1974 General Motors cars and trucks with a V8
engine and Delco-Remy distributor. But these points can be adapted for use
on Kohler [pulling] engines with use of a fabricated angle bracket (see below)
for easy adjustment of the ignition timing with an Allen wrench. (Limited
quantities - available while supplies last.) And contact
Lakota Racing or
Midwest Super Cub if you need
an angle bracket to mount your Chevy points. |
|
 Chevrolet (GM)
V8 condenser (for battery ignition only). Can be substituted for Kohler's
[battery ignition] condenser on the single and twin cylinder flathead cast
iron block engines with no problems. Also used on most older farm tractors
and virtually all pre-1974 automobiles. Wire length: approximately 3".
$1.50 each, plus shipping. (Limited quantities - available while
supplies last.) |
|
| If an air-cooled small engine has battery ignition, to allow the points to last longer, try the PointSaverTM Electronic Ignition Unit available from http://www.kirkengines.com. It works great for general yard use and pulling tractors! Also, MSD offers a module to help points last longer, too. Although Ford Motor Co. originally made the Transistorized Ignition Module, which works the same as the PointSaver, it's a transistorized breaker point ignition system that was used in various Ford vehicles from 1965 to 1972. Go here to make your own transistorized point ignition module: http://www.cs.berkeley.edu/~wkahan/TransIgn.pdf. The only problem with using this module is the point contacts may become oxidized or lightly corroded if the engine sits for a long period of time because there's not enough "spark" or electrical current between the contacts to burn away the oxidation. Or two or three condensers can be used with an ordinary or high-performance coil to help the points last longer at higher rpms. | |
  Points and condenser set for certain models of Clinton and
all aluminum block Tecumseh engines. Replaces Tecumseh part # 30547A (points).
Replaces Tecumseh part # 230548B (condenser; body length: .931", width: .531";
wire length: 5-1/2".). $8.00 each set, plus shipping. |
|
 Magneto Ignition
Coil for Clinton, Kohler K-series flathead cast iron block and all aluminum
block Tecumseh engines with point-type ignition. Replaces Tecumseh part #
30560A, Tecnamotor # 1633.0001, Kohler part # 232901-S & 47-755-20s
(obsolete), Clinton # 135-13-990 and Phelon # FG-6240. Fits Clinton, early
Tecumseh and early Kohler K-series flathead cast iron block engines.with
coil/stator under flywheel. (This part is no longer available from Kohler.)
Spark plug wire length: 17". Works great when connected to the NOVA II electronic
ignition module! (See below.) Dimensions: square hole through the middle
is .393" x .393", width is 1.050" and o.d. is 1.62". $25.00 each,
plus shipping. Part # 31-1884 |
|
NOVA II Electronic Transistorized Solid State Ignition
Module
|
|
| Quality
spark plugs (H10, J19LM, J8, J8C, etc. Please specify which type you need.)
- $2.50 each, plus shipping. |
 Spark Strength Tester. Handy,
easy to use, clamp-on style. $6.00 each (plus shipping). |
 Heavy duty, standard output
(20,000 volts) 12 volt oil-filled canister ignition coil for battery ignition.
2" diameter. Can be used on most garden tractors, older farm tractors and
virtually all pre-1974 automobiles. NOTE: This particular coil comes with
no mounting bracket and does not require an external ballast resistor.
$25.00 each, plus shipping.
NOTE: If you need a bracket for this coil, you can get one at a local auto parts store, do a search on eBay or contact either JEG'S Chrome Coil Bracket or MSD Ignition's Coil Bracket. |
Quality Black Hypolon-Copper Core Spark Plug Wire. 7mm diameter, 20" long. $15.00 each, plus shipping. |
 Battery Ignition
Conversion Kit.
Convert virtually any air-cooled, single cylinder cast iron and certain aluminum block small gas engines with a magneto ignition system (having points and condenser) to battery ignition. Includes new 12 volt coil (automotive canister-type), condenser (Kohler) and 25-1/2" long 7mm copper-core spark plug wire. $46.00 each kit, plus shipping. |
|
| New points, condensers and spark plugs for other makes and models of engines are also available. Please call or email me for your needs. | |
 Dixson Precision Handheld Wireless Analog Tachometer
Accurately determine the rpm of any air-cooled small gas engine by using a quality wireless tachometer, such as the handheld tach by Dixson. This is a precision handheld solid state wireless tachometer with an analog reading. The antenna is held near the spark plug wire and it gives a correct reading rpm for all 2 and 4 cycle single and twin cylinder engines with magneto or battery ignition. Selector switch gives 0-5000 RPM low scale or 0-15000 RPM high scale. Note: Divide the reading by half on engines with camshaft operated ignition points. Works perfect when performing a tune-up, setting the rpms on all stock pulling tractors when rules require a limited rpm, and testing the rpm on high-performance engines. Uses one 9 volt battery, which is included with purchase. Manufactured by Dixson. $100.00 each, plus shipping. Top of page |
|
Universal and high-performance.
Improves engine performance by stabilizing the spark, much like crank trigger
ignition does. Durable die-cast aluminum housing. Produces a hot spark even
at cranking speeds, is weather-proof and very reliable. Ignition timing is
automatically set. No kick-back and no timing adjustment required. Works
excellent!
What is the best spark plug to run in a garden pulling tractor, stock or otherwise?
An
OEM-type plug, Champion H-10, the one that the factory originally install
in the 10-16hp Kohler engines works great for pulling. Although the AC 45
plug works great, too. From time to time I've ran various spark plugs that's
designed for small engines, and I couldn't tell any difference whatsoever
in the performance of my tractors. Although it's a good idea to use a
non-resistor spark plug and a non-suppressor type (carbon core) spark plug
wire. By doing this, more voltage will reach the spark plug's tip. The use
of a "cold" or "hot" spark plug (heat range) doesn't really matter because
most pulling engines have no cooling system to cool the plug. (When there's
no fins on the flywheel (steel flywheel) or an electric fan running, nothing
will cool the engine.) And in my experience, it seems that it makes no difference
of what type of spark plug works best for either gas or methanol fuel. But
a wider gap (.060") works better with methanol. And gas works just fine with
a standard gap of .035".
Installing dual spark plugs is not recommended and doesn't help in
the increase of power whatsoever. Simply because one plug will be running
hot (exhaust side) and the other will be cool (intake side). Engine power
is generated from the heat source. Because heat is how an engine produces
power. So it's best to install just one spark plug positioned in the cylinder
head in the area between the piston and exhaust valve with the plug gap set
at .060". Because the .060" gap will simulate as having two spark plugs.
Using a high performance coil will help.
Indexing of
the spark plug will help in power, too. This is when the gap faces the
center of the piston. Return to a previous
page or paragraph.
For anyone who's wondering, an ordinary automotive battery-type condenser and an automotive canister-type ignition coil will work on any one or two cylinder air-cooled engine that use the battery ignition system. When using two automotive ignition coils on a twin or two cylinder engine with conventional points, be sure to use two condensers as well, one for each coil , only if the coil(s) requires one. Otherwise, the engine will idle, but won't rev up. And there's a very little difference between a Kohler battery-type condenser and an automotive [Chevrolet/GM] condenser. So either can be used on a Kohler engine.
If a flathead Briggs & Stratton twin cylinder engine has points, it can be easily converted to battery ignition (for a hotter spark and more power). The B&S ignition points can be used, but two automotive canister-type ignition coils (with spark plug wires), and of course, two battery ignition condensers will have to be used. The spark plug gaps will need to be set at .035", and the ignition timing can be set by the gap of the points (.020") or with an inductive timing light after the flywheel is degreed in with timing marks.
Typical Battery (Points and Condenser) Ignition System for a Garden Tractor
If your ignition coil has a BUILT-IN resistor, connect the wires as shown
below...
But if your coil requires an EXTERNAL resistor, connect the wires as shown
below...
Setting the [Point] Ignition Timing on Virtually Any Small Gas Engine -
The point gap on virtually all small gas engines, rather if it has one or two cylinders, is set at .020" using a feeler gauge with the piston positioned at TDC on the compression stroke. This is when the valves (#1 cylinder for a twin cylinder) are fully closed. This sets the ignition timing approximately at 20° BTDC (Kohler engines), and is the most easiest and simplest way to basically set the timing. A better way is to statically set the timing. But the most accurate way to dynamically set the timing is to use an automotive inductive timing light.
To statically set the ignition timing on an engine with a stock flywheel is with a multimeter (analog or digital) set on OHMS, or with a 12 volt test light and a battery or 12 volt power source to power the light. To make this happen...
-
Connect one lead of the multimeter
or test light to the ignition points terminal screw or the points wire
(disconnect it from the ignition coil first) and the other lead to engine
or tractor ground so that the points will serve as a switch to activate the
meter or light. To test the connection, set the points gap at .020" with
a feeler gauge and then slowly rotate the crankshaft (flywheel) back and
forth when the points open and close to see if the meter is activated or
light comes on and goes off. IMPORTANT: Always clean new or used points
contacts with a wire wheel, quality steel fingernail file, a small, thin
steel "point file" or small, thin special purpose file to remove any oxidation
(light corrosion) that can form on them while in storage. If this isn't done,
it could cause a faulty connection. And then, after setting the gap, close
the gap and pull a clean piece of white lint-free paper through the contacts
to remove any oil or dirt that may not be visible to the naked eye on them.
Don't use sandpaper or emery cloth to clean the contacts! They'll leave grit
between them (which is hard to remove) and cause a bad connection.
-
On the OEM cast iron flywheel,
place a bright colored paint mark at the S mark [line] on the flywheel.
The S mark is located exactly 20° BTDC (above) the T mark.
S stands for Spark Advance, which is where the timing is set at. T stands
for TDC. The flywheel may need to be cleaned to see the marks. If there is
no visible S mark, then it's located exactly 1-5/8" (1.625") above
the T mark. This cannot be done with an aftermarket steel flywheel
having no timing marks.
- If there's a timing site hole in the rear of the bearing plate, then the timing marks are on the backside of the flywheel. If the marks can't be seen, then the flywheel will need to be cleaned off and depending on type of camshaft, a bright colored paint mark needs to placed at the T (older two-piece cam) or S mark (newer one piece cam).
- Slowly rotate the flywheel back and forth by hand when the timing marks are aligned and at the same time the ohmmeter should show an intermittent connection or the test light should flicker. If necessary, widen or narrow the points gap until the points make contact the same time the timing marks are aligned. It is at this position when the ignition timing is accurately set.
- Timing for gas fuels - usually 22° (low octane) to 30° (high octane) BTDC.
- Timing for E-85 fuel - 25° BTDC.
- Timing for methanol or methanol/nitro mixture - usually 25° to 35° BTDC.
- As the points contacts wear, it's a good idea to check the timing periodically.
Another simple
way to set the ignition timing is to use a dial indicator to measure the
distance of the piston from the top of the block. On the 10hp Kohler engines,
the points just begin to open when the piston is located exactly at .125"
BTDC. And on the 12, 14, 16hp flatheads and 18hp OHV engines, the points
just begin to open when the piston is located exactly at .100" BTDC. Take
into consideration if the piston doesn't come flush with the top of the block,
or if it pops out of the cylinder. Distances shown is when the S mark on
the flywheel is aligned with the mark on the bearing plate.
EXCEPTION: When setting the ignition timing on an older Kohler engine with the old style two-piece camshaft, set the points so they just begin to open with the piston positioned on the compression stroke at 0° TDC (T mark on the flywheel). When the engine starts, the points lobe rotates and automatically advances the timing to 20° BTDC. Don't set the timing at 20° BTDC (S mark) with the old style two-piece camshaft. Setting it at 20° BTDC will advance the timing too much and cause the engine to "kick back" when trying to start.
How to set the points on a Kohler engine -
Adjust the points by first positioning the piston at TDC on the compression stroke. Then slightly loosen the set screw on the points and place the flat screwdriver in the slot on the upper part of the points bracket to widen and narrow the point gap. Then use a .020" feeler gauge to set the gap.
For a more accurate setting of the ignition timing, use an automotive inductive timing light with the engine running at an idle. This cannot be done with an aftermarket steel flywheel having no timing marks.
On a Kohler engine, if the screw that fastens the points to the bracket is hard to get at with a screwdriver on the equipment, then install an Allen head screw and use an angled Allen wrench to adjust the points.
NOTE: If the ignition timing is set right and the engine kicks back, sometimes, but not always, then the compression relief isn't relieving enough compression. Try setting the valve clearances to specs and see if that makes a difference. If the timing is retarded to reduce the possibility of kickback, then the engine will run sluggish and not produce enough power.
Where
is the Timing Site Hole in the Flywheel Shroud?
On the small [8"] flywheel without the starter ring gear and with the starter/generator, the timing site hole is on the right when facing the front of the flywheel, or on the same side as the starter/generator. But on the large [9-1/2"] flywheel with the starter ring gear and gear starter, the timing site hole is on the left when facing the front of the flywheel, or on the same side of the carburetor.
To set the ignition timing on the 7hp and 8hp Kohler engines, there's a sight hole in the backside of the bearing plate on the starter/generator side, just behind the flywheel. It has a metal hole cover in it. Remove it & then slowly rotate the flywheel by hand until \you see the SB mark. place a white paint mark on it. Now connect the timing light & start then engine & then note if the mark appears in the sight hole. If not, adjust the points until the mark is centered in the hole. This is how you set the ignition timing with a timing light.
It is recommended that a steel flywheel be degreed in on an engine to locate true TDC. Mark the flywheel every 5 degrees out up to 35 degrees BTDC. Note: With a steel cam and ground-on point lobe, do not correlate points gap with engine timing – there is a range from approximately 10 degrees BTDC to 40 degrees BTDC! Use a continuity tester to set points to desired ignition timing by gapping points.
Ignition timing must be properly
set for any engine for it to produce full power. Ignition timing is set according
to when the piston reaches its Before Top Dead Center (BTDC) position in
the cylinder on the compression stroke. When measuring the piston distance,
take in consideration if your piston "pops" out
of the cylinder or if it doesn't come flush with the top of the block.
And don't trust strange markings on the flywheel.
For precise accuracy, use an ohm meter or a 12 volt test light in the points circuit, a dial indicator to measure the distance of the piston in the cylinder, fasten a degree wheel to the crankshaft flywheel end and you'll need to fabricate a piston stop. Or for a piston stop, on a flathead engine, a long reach spark plug can be used, and the cylinder head can be positioned it so the spark plug is over the piston.
A dial indicator, degree wheel and piston stop are also used in
degreeing in the camshaft. Check your local automotive
parts supply stores for a 12 volt test light, dial indicator and degree wheel.
If they don't have them in stock, they can probably order them for you. But
a piston stop will probably have
to
be fabricated from scratch. Each mark on the face of a dial indicator represents
one thousand of an inch (.001"). The marks with a number (10, 20, 30, etc.)
represents every ten thousands (.010", .020", .030", etc.).
With an aftermarket steel flywheel or a stock flywheel with no timing marks, the most accurate way to set the ignition timing [on virtually any engine] is performed by measuring the distance of the piston before it reaches top dead center with a dial indicator in conjunction with a degree wheel fastened to the crankshaft flywheel end. To learn more, read on....
Find TRUE Top Dead Center (TDC) on an Engine with a Steel Flywheel to Accurately Set the Ignition Timing! Parts needed are a degree wheel and a piston stop. Or on a flathead engine, a long reach spark plug can be used, and the cylinder head can be positioned it so the spark plug is over the piston.
- Connect the ohm meter or test light as described above.
- Remove the cylinder head from the engine.
- Fashion a rigid pointer from stiff wire or an old coat hanger and attach it to the engine block. This pointer locates the degrees on the degree wheel.
- With a degree wheel installed on the flywheel or PTO end of the crankshaft, and with the flywheel fastened onto the crankshaft, rotate the crankshaft by hand in normal running rotation until the piston at the very top of the cylinder with both valves fully closed (this is the Top Dead Center position on the compression stroke), and then adjust the pointer to zero (0º TDC) on the degree wheel.
- Now turn the crankshaft opposite the running rotation approximately 15-20 degrees. Install a piston stop on the top of the engine block fastened in place by two head bolts. NOTE: If your piston pops out of the cylinder at TDC, then to use a piston stop, you'll need to install several flat washers or a spacer between the piston stop and engine block so the piston will clear it and go past the TDC mark.
- Continue to turn the engine in the same direction until the piston comes back up and just touches the piston stop. Make a note of the exact number on the degree wheel that the pointer is on.
- Rotate the engine in the other direction (running rotation) until the piston comes back up and touches the piston stop. Again note the number where the pointer is.
- Remove the piston stop and rotate the crankshaft to the midpoint of the two marks. At this point the piston is at the true top dead center. Loosen the degree wheel and adjust it so it will read 0º TDC at the pointer. Don't rotate the crankshaft to do this!
- Slowly rotate the engine in reverse normal rotation. The test light should be on. If not, adjust the points so it is on.
- Rotate the crankshaft by hand in its normal direction until the degree wheel is where you want the timing to be set at (20º) and then adjust the points so they just begin to open. The test light should've gone off or flickered by now. If not, set the points so they just start to open and the light flickers. Once the degree wheel is in the proper position, the breaker points should just begin to open. Or, when using Crank Trigger Ignition, check or set the initial timing by positioning the center of the magnetic pickup coil (sensor) with the center of the trigger screw. It is at this moment when spark occurs. And it's at this point that the ignition timing is set correctly. Mark the flywheel or front pulley where the timing marks are on the degree wheel for setting the timing with an automotive inductive timing light in the future.
NOTE:
The above method is sufficiently accurate and useful in building a fresh
engine and not having to mess with adjusting the points just to get the engine
started for the first time. However, after getting the engine started, it's
always a good idea to use an inductive timing light to check to see if the
timing is truly set where it's supposed to be. This is setting the timing
dynamically. Use a timing light when the timing marks on both the bearing
plate and flywheel are aligned. The maximum setting for Kohler engines burning
GAS is 20-22° BTDC. NEVER run over-advanced timing (beyond the
22° setting) with gas just to try to get "more power" out of your engine!
All that'll do is seriously overheat the engine and ruin parts.
Return to previous paragraph.
Ê
If your engine has a compression relief on the camshaft and the valve clearance is set right (at least for the exhaust valve), chances are the engine won't "kick back" (when the flywheel/crankshaft suddenly and violently rotates in the opposite direction) when cranking it over to start it if the timing is set over-advanced. (This is terribly hard on the starter gear and shaft.) Therefore, this would be a false indication that the timing is set correctly. Always check it with a timing light to make sure!
Kohler engines aren't like car engines. You don't dwell-in the points on a Kohler engine. Instead, you set the point gap at .020" just to get the engine running, then you set the ignition timing by widening or narrowing the points gap until the timing is at 20° BTDC by observing the marks on the flywheel.
On Kohler flywheels, there should be a T and an S stamped into the edge of the flywheel. The T is for Top Dead Center (0º TDC), and the S is for Spark Advance (20º BTDC position). When setting the timing, always set it on the S mark. Don't trust setting the points with a .020" feeler gauge. Because the ignition timing may not be right at 20° BTDC, and the engine won't produce full power. If necessary, place a white paint mark on the flywheel and the bearing plate to see both of them clearly with an automotive inductive timing light. To adjust the ignition timing, widening the points gap advances the timing, and narrowing them retards it.
If you have the small diameter (8") flywheel, then the timing marks (on both the bearing plate and the flywheel) are located on the right side of the block, facing the flywheel. But if you have the larger 9" flywheel, the timing marks are on the left side of the block. To find the T mark on the flywheel (meaning Top Dead Center), rotate the crankshaft so the piston is exactly at top dead center position on the compression stroke. The S mark is located exactly 20° BTDC (above) of the T mark. S stands for Spark Advance, which is where the timing is set at. You may have to clean the flywheel to see the marks. If there is no visible S mark, then it's located exactly 1-5/8" (1.625") above the T mark. Apply a spot of white paint on the S mark so it'll be easier to see where to set the timing with a timing light.
This is how to set the [point] ignition timing on older Tecumseh engines:
First of all, on virtually any spark-ignition engine, advancing or
retarding of the ignition timing is performed by widening (advancing) or
narrowing (retarding) the ignition point gap, and on Tecumseh engines, it's
also performed by rotating the stator. (The thing the points, condenser
and coil are fastened to.) On a Tecumseh engine, the points gap is supposed
to be set on the high spot of the rubbing block or points lobe that's on
the crankshaft, located underneath the flywheel. There are no points lobe
on the camshaft.
NOTE: If the ignition timing is set right and the engine kicks back, sometimes, but not always, then the compression relief isn't relieving enough compression. Try setting the valve clearances to specs and see if that makes a difference. If the timing is retarded to reduce the possibility of kickback, then the engine will run sluggish and not produce enough power. |
How To Read A Dial Indicator -
| Each mark on the face of a dial indicator represents one thousand of an inch (.001") graduations. The marks with a number (10, 20, 30, etc.) represents every ten thousands (.010"). Depending on the size of the engine, for a reading of .050" or .070" BTDC, first, run the piston up at true TDC, then set the dial indicator at the .050" or .070" mark. Then, slowly rotate the crankshaft in opposite of normal engine rotation until the needle reads 0 degrees BTDC. The needle will move in the counterclockwise direction (back to the 0 degree mark) as the piston moves downward in the cylinder. |
The timing also greatly depends on where the spark plug is located in the combustion chamber. Most plugs are centered in the combustion chamber. But if it's closer to the exhaust valve, the timing must be advanced slightly more.
For METHANOL fuel, if the spark plug is positioned in the center of the combustion chamber, set the timing at 24-26° BTDC. If the plug is located closer to the exhaust valve, the timing needs to be set to about 30°. If the plug is directly over the exhaust valve, the timing needs to be at 38° to obtain full power. 38 degrees is the maximum setting for methanol fuel. Location of the spark plug in the combustion chamber and proper ignition timing are two things that's very important in engine performance. Actually, it's best to set the timing with some test pulls or with the engine connected to a dynamometer or "engine dyno." Return to a previous page or paragraph. Return Ê
Isn't it a pain having to constantly adjust or set the ignition timing on your Kohler pulling engine? To fix this problem, the best type of ignition points to use for pulling are ordinary Kohler points. The spring on Kohler points is much stiffer than the one on Chevrolet (GM) V8 points. And because the clamping screw locks in position, the adjustment won't slip with Kohler points due to normal engine vibration. Chevrolet points are nice because they're much easier to adjust the ignition timing, but will sometimes slip out of adjustment because the adjusting screw cannot be securely locked in position.
How to Fix the Problem with a Worn Points Lobe on the Camshaft -
Sometimes the point lobe on a Kohler camshaft will get worn so badly that
the timing can't be advanced enough to get adequate power out of an engine.
But only on the 10-16hp flatheads and 18hp OHV engines there's a way to fix
this, and there's no need to purchase a new high-dollar camshaft or do any
welding on the old one. To fix a worn point lobe... first, you must disassemble
the entire engine. Then, carefully cut some very short threads (about 3/32"
in length) squarely on one end of the point pushrod. And then thread a hardened
3/8" (wrench size) hex nut onto the rod.
By
doing this, the nut will make contact with the unworn areas of the lobe,
allowing full adjustment of the timing as if the lobe wasn't worn at all.
This can also be done for a lobe that's still in good shape, to keep it from
wearing later. And remember that the rod will have to be inserted from inside
the engine block.
And on the 7hp and 8hp Kohler engines, the nut will need to be turned down in diameter, and the inside of the block will need to be ground away for clearance of the nut.
The minimum length of the Kohler 10-16hp flatheads and 18hp OHV engines point
pushrod is 1.500" and the maximum length is 1.600". And the minimum length
of the Kohler 7hp and 8hp engines point pushrod is 1.250" and the maximum
length is 1.260". If it's too long, the points' contacts won't touch and
the rod will need to be shortened. But if it's too short, the contacts won't
open enough or at all and the rod will have to be replaced with a longer
one. So measure accurately before (re)installing! The diameter is .184".
If
doing the above didn't help to advance the timing quite far enough (for gas
and especially methanol fuel), grinding (and polishing) of the lobe may need
to be done. Grind about .050" deep into the surface just before the lobe
(see drawing to the right) and about 1/2" from the lobe and right next
to the lobe, but not on the lobe itself! A die grinder with a porting
stone works excellent for doing this. After doing this, the timing can then
be advanced as far as 50º BTDC!
By the way - I found the only way to keep the crankcase oil from getting onto the ignition points on a Kohler engine is to install a small tight-fitting rubber/neoprene "O" ring on the points pushrod. Place the ring on the outside and close to the engine block. The oil will then travel out to the "O" ring, and drip off, staying off the points. Actually, the best thing to do is install a new steel pushrod. Because the OEM aluminum ones wears too easy, allowing the oil to seep out.
Be Professional With Your Wiring!
When wiring up your electrical system, don't just make a connection by twisting
the wires together by hand and then taping them up. All that does is allow
moisture to enter between the two wires and in time, lets corrosion to set
in, causing a faulty connection. Instead, solder the wires together, then
tape them up or use some heat-shrink wrap. Or use "crimp" style wire connectors
to connect the wires together or to connect a wire onto a switch or terminal.
Route the wiring along the inside of the frame in a safe manner, away from
any rotating parts, hot exhaust areas and for a "cleaner" look.
Crank Trigger Electronic Ignition Section - Top of page
Okay, so you've got a fancy carburetor or fuel injection, custom-machined billet cylinder head, larger valves, high performance camshaft, forged piston, billet connecting rod, steel crankshaft, etc., but you're still running the old-fashioned points and condenser ignition system? Use the latest state-of-art technology! Upgrade to Crank Trigger Electronic Ignition for durability and to be truly competitive on the track!
This is the era of modern wonders, where everything is transistorized, digitized and miniaturized. Yet even today, many garden tractor pullers still use breaker point ignitions on their garden pulling tractors. For other people, the frustration of attempting to keep a breaker point-fired tractor in peak running condition has been enough of a reason to join the electronic era. Breaker point systems do have some positives, though. Points are cheap and somewhat easy to install. And many pullers are comfortable with setting-up their points. But for the utmost precision ignition timing and maintenance-free convenience, crank trigger electronic ignition is the way to go!
Tired of changing or constantly adjusting the ignition points? Convert to electronic ignition! For improved performance, easier starting, and less moving parts to leave your tractor dead on the track. Shock and moisture resistant, and all it takes is a few simple hand tools to install. In my opinion, getting rid of the points and condenser has been the best advance ever in engine technology.
Virtually Any Engine Can Be Converted To Crank Trigger Ignition!
If an engine is connected to a battery (and if it has a charging system to keep the battery fully charged for prolong use), and if there's room on the PTO end of the crankshaft for the trigger disc, and a place to mount the bracket for the magnetic pickup coil, then the engine can be converted to crank trigger ignition!
Stable ignition timing is a necessity in high performance engines. In most cases, a points ignition will do just fine, but when you start making big time horsepower with extreme cylinder pressures and higher rpms, the timing is critical to both the performance and life of the engine. The ignition must be triggered at a precise time in relation to the position of the piston during the compression stroke. However, the timing can get erratic or fluctuate at higher rpms with the points system, due to camshaft end play, clearance in both the crank and cam gears and mechanical flexing that takes place through the camshaft support pin, especially when using a high lift cam with very stiff valve springs. In fact, if you ever checked the timing on your engine with camshaft-operated points using an inductive timing light, you may have noticed that the timing marks will fluctuate or "jump up and down" a few degrees. And it'll fluctuate more as the engine rpm increases. This won't happen with crank trigger ignition. It totally eliminates spark scatter or fluctuations and erratic timing problems common with point ignitions. With crank trigger ignition, the "tighter" the main bearings are, the more stable the timing is.
The crankshaft knows exactly where the piston is, plus it is the most stable component in an engine in relation to piston position. That's why a crank trigger ignition is so important in high-horsepower/high rpm engine applications. With this ignition, you get absolutely stable timing with ± 1/10th of a degree of accuracy from 0 to 15,000+ rpm without missing a beat (depending on the size of the transistor in the control module). The ± 1/10th of a degree is the result of the clearances in the main bearings. With a quality electronic ignition control module, the crank trigger ignition system will work flawlessly without missing a hit even if your engine can turn up to 100,000 rpm! Because it works as fast as electricity can travel. As long as it's installed and adjusted correctly, it'll help an engine scream down the track. Also, with the crank trigger ignition system, you can set the ignition timing and forget it!
Crank trigger ignition is when the mechanical breaker points and condenser are totally eliminated and replaced by solid state transistorized circuitry. Actually, it works on the same principle as the electronic ignition that's used in the older automobiles (before computerized ignition systems). The conventional points ignition system is considered as old-fashioned technology by today's standards. Even the [high dollar] aftermarket adjustable ignition plate that's made for Chevy points is considered old-fashioned by today's standards!
Using points versus crank trigger is up to you. Personally, I prefer the crank trigger setup because it's very reliable and virtually maintenance free. Points are always burning and getting out of adjustment. Points always go bad or wear out. The contacts on points can get dirty, worn, burnt, oily (oil seepage from the crankcase), out of adjustment, wet (whenever the tractor is washed off or rained upon) or even oxidized (light corrosion). The use of a high performance ignition coil can shorten the life of points. And the condenser can go bad. Because a high performance ignition coil draws more amps from the battery, they will sometimes burn a good set of ignition points in a short time. But high performance ignition coils have no effect whatsoever on the Chrysler or Ford electronic ignition control module (ECU), even if two coils are used. And crank trigger ignition is much safer than points. Because ignition points creates a spark (which is normal), there's always danger of a fire if there's ever a fuel leak. The only spark that occurs with crank trigger ignition is at the spark plug's tip.
At
very high rpms (well above 4,000 rpm), with conventional points and condenser
ignition, the ignition coil operates at about 80% efficiency. The same is
true with high performance coils because they require more amps. But with
crank trigger ignition using the Chrysler or Ford electronic ignition control
module, any type of coil operates at 100% efficiency at any
rpm, which produces a much hotter and stable spark. This is why General Motors
refers to their 1974 to 1986 electronic ignition as HEI, or High Energy Ignition.
The reason there's a hotter spark is because at higher rpms, there's no condenser
to break down the voltage in the primary circuit in the coil. Plus, with
crank trigger ignition, the duration of each spark lasts about twice longer
(longer spark time), than with point ignition.
Crank trigger ignition system will work on virtually any garden tractor with
either a single or multiple cylinder engine. It'll also work equally on a
two cylinder engine as it does on a single cylinder engine. Crank Trigger
will spark on each compression stroke for each piston when used on a twin
cylinder engine. It'll also work excellent on any 2-cycle engine, because
it fires on every stroke of the piston. On a twin or two cylinder engine,
use just one Chrysler or Ford electronic ignition control module, one magnetic
pickup coil, one trigger screw in the trigger disc located at approximately
20º BTDC on the compression for the #1 cylinder. It'll spark for the
#2 cylinder at 20º BTDC on the compression stroke, too. And you could
install two ordinary automotive ignition coils, one for each cylinder. Wire
them together as you would for one coil. As the trigger screw passes the
pickup coil, a spark will be produced for each cylinder, one piston being
on the compression stroke and the other on the exhaust stroke and vice-versa.
It'll work identically the same as Briggs & Stratton's Magnetron ignition
on their twin cylinder flathead (valves in block) engines. Because the flathead
Briggs twins use a single ignition coil. But the Vanguard use two ignition
coils, one for each cylinder. Crank trigger ignition will also work on the
Vanguard, but two trigger screws must be installed in the trigger disc, one
for each cylinder. Just make sure that the location of the trigger screws
(the timing for each cylinder) is set right! By the way, the stock timing
on Briggs engines for gas is set at 11º BTDC.
To advance the timing for methanol fuel, a special-made flywheel
key must be used. They come in 2º, 4º, 6º and 8º increments.
Use the 6º one for a setting of 17º BTDC. These flywheel keys are
used mostly in racing go-karts and Junior Dragsters. You can get offset flywheel
keys from
Russell
Karting Specialties
(http://catalog.russellkarting.com/index.php?cPath=354_363_383&osCsid=d95d51e206e2c56183b908dd3b7f2a67),
500 S. Lincoln, Raymore, Missouri 64083, Phone: 1-816-322-3330, Fax:
1-816-322-2860, Email:
sales@russellkarting.com.
And an offset flywheel key can be used in a Kohler Magnum engine (that has solid state ignition) to advance the ignition timing when burning either E-85 or methanol fuels. Have an offset steel key machined, like the ones that Briggs & Stratton racing go-kart engines use.
Degree Increments for a Super Spacer or Indexing Fixture with a 3-Jaw Self-Centering Scroll Chuck -
The chart below is for installing multiple trigger screws in the trigger disc for crank trigger ignition on a multi-cylinder engine. NOTE: The degrees shown is not for the spark to occur at 0º TDC for each cylinder. They are so each cylinder will have equal timing or distance of spark between them. [Print this chart]
| Number of trigger screws to be installed -> | 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th |
9th | 10th |
| For a 2 cylinder engine -> | 0º | 180º | ||||||||
| For a 3 cylinder engine -> | 0º |
120º | 240º | |||||||
| For a 4 cylinder engine -> | 0º | 90º | 180º | 270º | ||||||
| For a 6 cylinder engine -> | 0º | 60º |
120º | 180º | 240º | 300º | ||||
| For an 8 cylinder engine -> | 0º |
45º |
90º |
135º | 180º | 225º | 270º | 315º | ||
| For a 10 cylinder engine -> | 0º | 36º | 72º | 108º | 144º | 180º | 216º | 252º | 288º | 324º |
If installed correctly, nothing could possibly go wrong with the crank trigger ignition system. Mainly because everything is totally sealed. There's no moving parts to wear and it could very well outlast the life of your tractor, even when used in high performance conditions! It's virtually maintenance free, extremely reliable. That's why auto manufacturers, virtually all small engine manufacturers (Kohler's Magnum engines ignition system operates much like crank trigger ignition) and most high performance/racing vehicles nowadays use electronic [or better yet, computerized] ignition. Plus it's something fancy to show off. It's powered by full 12 volts and features a more stable spark than the convention point ignition. You can also use your existing standard ignition coil or you can get a high vibration one from JEG'S or Summit Racing. And remember, a high performance coil will draw more amps from the battery.
Crank trigger ignition will work on virtually any small engine, but only if there's room on the crankshaft (preferably the PTO end, which is opposite the flywheel end) for mounting of the rotating disc that contains the trigger screw (see below Ê). On a single cylinder engine, this type of ignition will produce a spark on both the compression and exhaust strokes, which is harmless. Camshaft driven point ignitions only spark during the compression stroke. By the way, Kohler engine is mentioned here only as an example, because they're most common in garden tractor pulling.
The crank trigger ignition system is nothing to be afraid of. Once you understand how it works, it's actually quite simple and you'd feel more confident using it. Also, once you've tried this type of ignition, you'd be reluctant to go back to points. If everything else is set up correctly on your engine and tractor, once crank trigger ignition is installed and the timing is set right, it'll help bring your tractor to life and make it scream down the track! But if your engine already have a factory-installed solid state ignition that is triggered off the flywheel, you really don't need crank trigger ignition. Factory-installed flywheel-triggered electronic ignitions are very stable, reliable and they produce a powerful spark. But if you're installing a machined steel flywheel with no trigger magnets or pins on an engine that originally came with solid state ignition and/or there's no provisions (no threaded bolt holes present) on the block to install points, you will need the crank trigger ignition system.
If your Kohler Magnum engine originally came with breakerless ignition and it stopped functioning, and you're looking for an alternative ignition system, well, you have three options...
- Purchase a new high-dollar solid state module and put it back the way the factory intended.
- Drill new holes and cut threads in the side of the block to mount ignition points, install a condenser and an ignition coil. You'll also need a battery to power the ignition.
- Install a reliable crank trigger electronic ignition setup as described here in this web site. You'll also need a battery to power this type of ignition.
Items needed and details on how to install a Crank Trigger Electronic Ignition System (on virtually any engine) are listed below Ê Top of page
ü A Universal Magnetic Pickup Coil,
Crankshaft Position Sensor, Tach or Speed Sensor. Virtually any automotive
engine speed sensor or crank position sensor will work for this system. These
all work the same. These sensors require no power from the battery or module
because they self-generate an AC signal. Be sure to use a magnetic
one that produces a small electrical current whenever a small steel (nonmagnetic)
object is passed quickly over the end of it. Also, there needs to be a way
to mount it on the engine so the air gap and ignition timing can be set and/or
adjusted. A universal magnetic pickup coil is most common for this application.
It's an engine speed sensor (Tach Sensor) that threads into the bellhousing
of a late model truck with a Diesel engine for activation of the tachometer.
A crank position sensor is an automotive unit that threads into the engine
block and reads off a cogged wheel mounted on the crankshaft. It's for a
crank trigger ignition system that's on an automobile with a computer-controlled
engine that has electronic fuel injection.
Some GM crank position sensors have three or more wires, but
are activated by just two wires. The third (or other) wire(s) is a ground
or neutral and really have no purpose. When you buy a sensor, test it to
see which wires produce the electrical current, then just snip off the other
wire(s). And a used sensor can be easily tested by connecting it to a voltmeter
that's set on the lowest AC scale and then quickly pass the head of a small
steel bolt or nail back and forth close to the end of the sensor. If the
reading (digital type) or needle (analog type) fluctuates each time the metal
object passes it, the sensor is good. Also, the more voltage a sensor produces,
the hotter the spark. I sell 3/8" diameter universal
magnetic pickup coils further down in this web site.
ü A Chrysler, Dodge or Plymouth (MOPAR) Electronic Ignition Control Module (ECU). The stock Chrysler module works great on a garden pulling tractor for durability and all-out performance. Plus they're vibration-proof because the internal electronic components are sealed in epoxy. This means there's no internal wires to vibrate and break due to normal engine vibration. This type of module was used from 1972 through 1992, except on vehicles with the "lean burn" ignition. Also, tests has proven that an OEM/stock Chrysler module performs just as well as an after-market high performance [Mopar] modules when used on a garden pulling tractor. And the ignition timing stays constant with the Chrysler electronic ignition control module. Which means it doesn't advance or retard the timing at any rpm. I sell Chrysler modules further down in this web site.
Wiring Information for the Chrysler Electronic Ignition Control Module
|
The Chrysler Module Wiring Connections Are As Follows:
|
Wiring Diagrams for the Chrysler Electronic Ignition Control
Module
The control module or magnetic pickup coil could
burn up (possibly instantly) if the wires aren't connected to the right
terminals! When connecting the wires, take your time and make sure to use
different colored wires to avoid confusion. And be sure to fasten all wiring
securely to avoid breakage or loose connections from normal engine or tractor
vibration.
When mounting the Chrysler module, mount it away from excessive heat and remember that the exposed power transistor is electrically hot while the power is on. The unit should be mounted in an area which minimizes the possibility of shorting the transistor when working in the engine area. Shorting the power transistor to the heat sink or any ground could damage the unit.
Virtually any automotive parts supply store carries the stock type Chrysler
electronic ignition control module. They retail for about $21.00 and up.
Various manufacturer's part numbers are: EL110 (G.P. SORENSEN, available
at Advance Auto Parts stores); MPETP50SB (NAPA); LX101 (STANDARD); CBE14
(Borg-Warner); AL403 (NIEH); TP51 (ECHLIN, available at NAPA Auto Parts stores);
CH301 (FILK); CR109 (WELLS); E106 (KEM); C1900Z (AC DELCO) and AL-401 (NIEHOFF
IGNITION). Or just tell the counter person it's for a 1972 Chrysler Imperial.
And being a new Chrysler electronic ignition control module
wiring harness cost about $20.00-$45.00, I recommend getting the connector
w/wire leads off a 1972-1992 Chrysler, Dodge or Plymouth vehicle that's in
a salvage yard. But if you want to get a new one, the part number is Standard
S-516. For accurate and detailed wiring information and diagrams, please
click here or scroll down further in this
web page.
ü A Ballast Resister or a Full-Length
Resistance Ignition Wire.
The Chrysler electronic ignition control module (off any 1972-85 Chrysler,
Dodge or Plymouth vehicle), whether if it's a stock or a high performance
one, require a ballast resistor (off any 1955-57 GM vehicle) or a full-length
resistance ignition wire (off any 1958-74 GM vehicle) to prevent from putting
too much voltage into it and burning it up. A ballast resistor or resistance
wire is basically a voltage reducer that reduces 12 volts down to anywhere
between 6-9 volts, depending on the load. (The ballast resistor shown here
is the same used on the 1955-57 GM vehicles.) The reason the Chrysler module
doesn't have a built-in resistor is because as the resistor heats up while
the module is in operation, the heat from the resistor could travel to and
damage other sensitive internal electronic components within the module.
Here's Some Ballast Resistor Part Numbers:
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|
And if you've ever wondered about this, there's very little difference in the "ohms (d) resistance" of various automotive ballast resistors. So it really doesn't matter which one to use with the Chrysler module. The "ohms resistance" is just the amount of load or amps that a resistor can handle. And the stock Chrysler module draws very few amps.
ü Another type of electronic ignition control module that works great for crank trigger ignition is one that's made for certain domestic Ford, Lincoln and Mercury vehicles. This type of unit operates off of full 12 volts, which means it does not require a ballast resistor. The correct module to use has a blue grommet and comes with its own wiring harness. Here's a list of Ford and Motorcraft Numbers for the Ford Blue Grommet Ignition Control Module:
| Auto Parts Stores Cross Reference - FF402 (NIEHOFF); MF-481 (Mitech); F0306 (Filko); F102 (AmpcoWells); E302 (Kem); EL107M (G.P. SORENSEN, available at Advance Auto Parts stores); LX203 (STANDARD); F1910 (AC DELCO), ECHTP36 or ECHTP40 (ECHLIN, available at NAPA auto parts stores); F100 (Duralast).
Ford -
Motorcraft - |
Donor Vehicles - American Motors: AMX 78-80; Concord 78-81,83; Eagle 80-81, 83-87; Gremlin 77-78; Hornet 77; Matador 77-78; Pacer 77-80; Spirit 79-81,83. Ford: Bronco 76-87; Custom 75-77; E Van 89-89,95; Elite 75-76; Escort 81-82; EXP 82; F Pickup 76-87,97; Fairmont 78-83; Fiesta 78-80; Gran Torino 75-76; Granada 75-82; LTD 75-86; LTD II 77-79; Maverick 76-77; Mustang 79-85; Mustang II 76-78; P Series 76-77; Pinto 76-80; Ranchero 76-79; Ranger 83-88; Tempo 84-87; Thunderbird 75-83; Torino 75-76. Jeep: Cherokee 77-85; CJ5 77-83; CJ7 77-86; Grand Wagoneer 84-87; J Series 77-87; Scrambler 81-85; Wagoneer 77-85. Lincoln: Continental 76-80, 83-85; Mark IV 76; Mark V 77-79; Mark VI 80,82-83; Town Car 82-83; Versailles 77-80. Mercury: Bobcat 76-80; Capri 77-76,79-86; Comet 76-77; Cougar 76-84; Grand Marquis 76-83; LN7 82; Lynx 81-82; Marquis 76-85; Monarch 76-80; Montego 76; Topaz 84-87; Zephyr 78-83. |
Wiring Information for the Ford Electronic Ignition Control Module
|
The Ford Module Wiring Connections Are As Follows:
|
Wiring Diagram for the Ford Electronic Ignition Control
Module
The control module or magnetic pickup coil could
burn up (possibly instantly) if the wires aren't connected to the right
terminals! When connecting the wires, take your time and make sure to use
different colored wires to avoid confusion. And be sure to fasten all wiring
securely to avoid breakage or loose connections from normal engine or tractor
vibration.
ü Another type of electronic ignition control module that works for crank trigger ignition is the Chevrolet (GM) HEI (High Energy Ignition) 4-pin module. They're very small, compact and used on many non-computer GM cars and trucks with an L4, L6, V6 and V-8 engine from 1975 to late 1980s. They operate on full 12 volts, which means a ballast resistor is not required, unless it's for the ignition coil. But not all OEM GM HEI modules will work well for a garden tractor engine. Although certain stock modules do perform well and will allow an engine to rev up at very high rpms, while others will allow an engine to rev to about 2,500 rpm, then the engine will die off. But high performance modules works best and have an unlimited rpm. I'm not sure which stock modules works allows an engine to rev up at very high rpms, so when choosing a module, use your own discretion as to which one will work best.
In a multi-cylinder, distributor-fired engine, like in the automotive L4, L6, V6 and V8 engines, the GM module only works half the time. It doesn't fire on the exhaust strokes of these engines. Therefore, an ordinary stock module will allow an automotive engine to rev up to just 5,000 rpm, and no higher. But when used for a single or twin cylinder small engine with the crank trigger ignition, the GM module will fire every revolution of the crankshaft, on the compression stroke and the exhaust stroke. This means it must perform "double duty," in which the tiny resistor inside a plain, stock module can't react quick enough at higher rpms. So the engine shuts down at 2,500 rpm.
Stock OEM HEI 4-pin ignition module are part numbers: ECHTP45, Wells DR100, Niehoff DR400, Standard LX-301 and AC DELCO D1906. These modules are available from most auto parts stores. Be sure to use dielectric grease (or virtually any high quality grease) under the module before mounting it to help keep it cool. High performance modules are available from:
|
|
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Wiring Information for the HEI Electronic Ignition Control Module
|
Here's how to connect the wires. The four HEI module terminals are marked
with W, G, B and C.
|
Wiring Diagram for the HEI Electronic Ignition Control
Module
The control module or magnetic pickup coil could
burn up (possibly instantly) if the wires aren't connected to the right
terminals! When connecting the wires, take your time and make sure to use
different colored wires to avoid confusion. And be sure to fasten all wiring
securely to avoid breakage or loose connections from normal engine or tractor
vibration.
NOTE: Not all automotive electronic ignition control modules will work adequately for the crank trigger ignition system! Because some modules have a small transistor, which can't react quick enough to the increased rpms when triggered directly off the crankshaft. They're made to operate off the magnetic pickup coil that's positioned inside the distributor in an automotive engine that rotates half the speed of the crankshaft, which fires every other revolution per piston travel. So when choosing a module, make sure that it can handle increased rpms, at least up to 4,000 rpm (for a stock engine) and 15,000 rpm for a fully modified engine. And for stable ignition timing, the triggering device must operate directly off the crankshaft. And although the MSD control box will work excellent for the crank trigger ignition, it's not a good idea to use it on a garden pulling tractor because the wires inside the box have been known to break due to normal engine/tractor vibration. When using any type of module, make sure the internal wires and components are epoxy sealed to prevent vibration and breakage.
If you have doubts that an ignition control module is defective, you can have it tested (usually free of charge) at virtually any auto parts store.
The only reason any engine would need the ignition timing retarded or a spark advance system is so the piston won't "kick back" (when the flywheel/crankshaft suddenly and violently rotates in the opposite direction) when cranking over to start it. (That's when the crankshaft momentarily rotates or rebounds in the opposite direction.) All small gas engines nowadays have a compression relief mechanism on the camshaft (that opens the exhaust valve slightly halfway on the compression stroke), which allows the engine to crank over easily without kicking back. And most pulling engines have a long duration camshaft with the compression relief mechanism (if using a cast cam) and a heavier-than-stock [steel] flywheel. Which will also allow an engine to crank over easily without kicking back when starting. So you see, a spark advance really isn't necessary.
ü
An aluminum or steel flat or angle bracket to mount the magnetic pickup
coil. To prevent vibration of the pickup coil, and to prevent it from hitting
the trigger screw or disc, which will destroy the pickup coil, the steel
bracket (flat or angle) should be made of minimum 1/8" thickness. The aluminum
flat bracket should be made of minimum 3/16" thickness. And the aluminum
angle bracket should be made of minimum 1/4" thickness. The flat bracket
needs to be 3" wide x 2-1/2" tall. And the angle bracket needs to be a minimum
of 1-1/4" x 1-1/4" x 5" long, for the upper mounting position.
The angle bracket mounts above the trigger disc on the PTO end of the engine block, and the flat bracket mounts on the side of the engine block, over the threaded ignition points mounting holes. The flat bracket is fastened directly over the points mounting holes, using the threaded holes to secure it to the engine block, and it extends toward the rear of the engine (PTO end). Cut threads (3/4-16 NF) in each bracket to mount the pickup coil stationary or use a milling machine to accurately grind a 3/4" wide x 1-1/4" long slot and then use two jam nuts on the pickup coil in the slot to adjust the timing and to secure the pickup coil in place. Mount it on the PTO end of the engine block.
Measure the bolt pattern on your particular engine's PTO end to determine where the mounting holes should be drilled. Kohler 's two upper bolt holes on the PTO end are spaced 3-7/8" apart. If your particular engine doesn't have these holes, then two holes will need to be drilled and tapped, to accept the bracket. The two elongated mounting holes shown in the drawing above are not particularly necessary, but can be used in precisely setting the ignition timing. If the slots are used, make sure to install flat washers on the mounting bolts to avoid any future problems. Set the air gap between the pickup coil and trigger screw (in the disc below Ê) at a minimum of .008" and no more than .025" with a brass, plastic or paper (anything non-magnetic) feeler gauge. If the gap is wider than .025", the engine could misfire at high rpms due to normal engine vibration. And if the gap is closer than .008", due to normal engine vibration, the magnetic pickup coil could scrape the disc or trigger screw and damage could occur to the magnetic pickup coil, rendering it useless. So make sure to use a sturdy bracket and set the air gap accordingly! Once it's accurately set, it shouldn't need to be adjusted. I sell flat and angle brackets further down in this web site. Ê
ü A machined aluminum disc (don't use
steel, due to the magnetism in the pickup coil), made approximately 6"
in diameter and minimum 5/16" wide. Fasten the disc to a hub with a 1/4"
keyway and set screw to mount on the crankshaft PTO end.
Locate the timing mark on the disc and
then install a hardened steel (not stainless steel) 10-32 fine thread
(3/16" thread diameter) flat head screw (preferably an Allen head screw)
into the outer edge of the disc for use as the trigger screw. Countersink
the head of the screw into the aluminum so it'll be flush with the circumference
of the disc. Click here to learn the
correct way to cut threads. Use the bracket above for the magnetic pickup
coil to change and set the timing as needed. Scroll up in this web page to
learn the correct way of setting the timing and how to determine exactly
where to locate the trigger screw in the disc. By the way - this small,
light-weight screw will not effect engine balance.
I sell trigger discs further down in this web
site. Ê
One
could fasten the disc with the trigger screw next to an already existing
steel or aluminum starter pulley, with the disc being next to the engine
block. Or, one could fabricate an aluminum starter pulley with one side thicker
than the other (thick side toward the engine block), to install the trigger
screw into.
For safety and reliability, use a couple of "sleeves" made of steel, aluminum or plastic tubing to butt against each end of the hub and a bolt with a wide flat washer installed in the end of the crankshaft, in case the set screw in the hub loosens and to keep the hub/disc from coming off the end of the crankshaft. Of course, if this were to happen, the engine would die immediately.
Degreeing the Trigger
Disc -
To simplify degreeing the trigger disc, after finding true TDC on the disc, use a 6" protractor to make timing degree marks on the disc. Refer to the animated drawing to the right for identification. Hold the protractor on the disc, align the TDC zero on the disc with the zero on the protractor and then, facing the disc as if it were mounted on the PTO end of the engine, and with the magnetic pickup coil mounted either above the disc or on the side of the engine block, make the marks on the disc going counter-clockwise of the TDC mark. Going counter-clockwise of the TDC mark would be advancing the ignition timing, and clockwise of the TDC mark would be retarding it. Degree it as shown in the drawing below. But make sure that the marks on the disc are according to how the disc is going to be mounted on the crankshaft, with the center protruding hub facing toward the engine or away from it. Otherwise, the marks could be on the wrong side of the disc. (Most of the time, the protruding part of the hub faces away from the engine.)
Set the ignition timing according to piston travel in the cylinder,
as mentioned earlier in this web
page. Install a timing degree indicator mark (with a felt marker) on
the disc and a mark on the engine block and then make a final check of the
ignition timing with engine running using an inductive timing light.
How it works:
The magnetic pickup coil is able to detect the presence of the trigger screw object without any physical contact. Each time the trigger screw in the rotating disc passes the magnetic pickup coil, this generates a small electrical current within the pickup coil. This current is sent in a form of a signal to the electronic ignition control module; within, a transistor opens the primary circuit in the ignition coil and the spark occurs. All this happens at the speed of electricity. The conventional ignition points and condenser ignition system is less responsive.
Checking for Spark -
Because this system produces a spark at very low cranking speeds, once installed, you can test for spark simply by rotating the crankshaft (rotating disc) back and forth by hand so the trigger screw passes the magnetic pickup coil. But turn the ignition switch on first. Also, after the engine has been ran, and because there may be some raw fuel remaining in the combustion chamber, crank trigger ignition will produce a spark at the spark plug one time each time the ignition switch is turned on. Sometimes this single spark will make an engine go "poof!" which is harmless in most cases.
By the way - I have not received any complaints from my customers or the readers of this web site concerning the crank trigger ignition about their engine(s) running erratic or cutting out at high rpms, unless of course, they installed a used/bad module.
Advertisement: (updated 5/26/09)
| If you can't do-it-yourself
or find someone else who can fabricate crank trigger ignition system or if
you want to purchase a partial kit, please contact me, Brian Miller, at:
A-1 Miller's Small Engine & Specialty Shop
(1501 West Old Plank Rd., Columbia, Missouri. 65203 | Phone: 1-573-875-4033).
Please call any day between 12 noon and 8:00 p.m. Central time, and please
be patient because I stutter. Fax: 1-573-449-7347. You can also contact me
through Yahoo! Messenger:
Crank Trigger Electronic Ignition Parts -
Crank Trigger Disc for Wheel Horse garden tractors. Mounts on side of OEM drive pulley with three 1/4" bolts. $60.00 each, plus shipping.
The best way to determine the rpm of an air-cooled small gas engine is by using a wireless tachometer, such as the handheld tach by Dixson. This is a precision handheld solid state wireless tachometer with an analog reading. The antenna is held near the spark plug wire and it gives the correct reading rpm for all 2 and 4 cycle single and twin cylinder engines with magneto or battery ignition. Reads 0 to 15,000 rpm in two scales.Works perfect when performing a tune-up, setting the rpms on all stock pulling tractors when rules require a limited rpm, and testing the rpm on high-performance engines. Uses one 9 volt battery, which is included with purchase. Manufactured by Dixson. $100.00 each, plus shipping to your zip code. |
3/8" diameter universal magnetic
pickup coil with two jam nuts and 30" lead wires. $65.00 each.
Using Crank Trigger Ignition
on a Cast Iron Block Briggs & Stratton or Tecumseh Engine
-
(Rewritten 12/22/06) Top of page
 For emission purposes, Briggs
& Stratton and Tecumseh has phased out their old cast iron flathead engines
to get people to buy their new OHV aluminum block engines. Tecumseh also
discontinued their solid state electronic ignition module some years ago.
And magneto coil/points ignition parts for the old B&S cast iron block
engines are getting hard to find and they're are very expensive. The cast
iron block B&S and Tecumseh engines are very good and reliable engines
and after the OEM ignition parts have quit functioning, the only alternative
is to install a crank trigger electronic ignition system on these type of
engines.
Crank trigger ignition will work on all cast iron block Briggs & Stratton and Tecumseh engines, But, unlike Kohler engines, most of these engines don't have a compression relief mechanism built into the camshaft. Instead, they start under full compression. The way Tecumseh engines start is their OEM solid state ignition module has a built-in ignition timing retard that automatically advances as soon as the engine starts. And B&S engines have an extremely heavy flywheel to prevent "kick back" (when the flywheel/crankshaft suddenly and violently rotates in the opposite direction) while cranking the engine. If crank trigger ignition were installed on either of these engines, the timing would have full spark advance at all times and if the engine has a lot of compression, the flywheel/crankshaft will probably "kick back" every time the engine tries to start. There are two ways make crank trigger ignition work on an engine without an automatic compression relief... With crank trigger ignition, and without a computer to automatically retard and advance the timing, the timing will need to be set normally, and install two separate switches - one being a push button to crank the engine with a gear starter and the other being an ordinary OFF/ON toggle switch to power the ignition. To make this work, first crank the engine, choke it and then flip the ignition switch to "put the spark to it." Doing this will allow it to start every time. Because the centrifugal force of the spinning flywheel makes it impossible for it to kick back. NOTE: The above method is also recommended for pulling engines (with points or crank trigger ignition) having a high performance camshaft and no compression relief to prevent bending or breaking the armature shaft in the gear starter when the engine wants to kickback. If a cam doesn't have a compression relief, then a .050" "hump" of weld can be placed on the base circle of the exhaust lobe on the camshaft just before the piston reaches TDC to relieve half the compression in the combustion chamber on the compression stroke.
And as far I know, no other ignition system will work on these engines. Also, being crank trigger uses a larger ignition coil, a battery ignition system (with either crank trigger or points) produces a hotter spark than any solid state or magneto ignition system. By the way - the OEM B&S or Tecumseh coil can't be used with crank trigger ignition. A magnetic pickup coil, which is described later in this web site, must be used instead. A special bracket must also be fabricated for the pickup coil. For a specifically designed kit to convert your cast iron block Tecumseh engine to crank trigger ignition, contact Ed Stoller at edstoller@earthlink.net. His web site is: http://home.earthlink.net/~edstoller/id5.html. |
Using an Electronic Ignition Distributor in an Older Automotive-Type Engine - Top of page.
If you
have an automotive-type gas engine in an old car or truck, farm tractor,
forklift, construction equipment, boat motor, etc., with a worn out or
troublesome point ignition distributor, and parts are no longer available
or you want to upgrade or convert it to the modern, more powerful, trouble-
and maintenance-free electronic ignition system, all your engine will need
is a battery-powered, non-computer controlled GM HEI [High Energy Ignition]
distributor (with the 4-pin control module) from a 1975-84 General Motors
vehicle (Chevrolet, Pontiac, Oldsmobile, Buick, Cadillac or GMC truck) having
an L4, L6, V6 or V8 engine. These type of distributors are considered high
performance because they produce a hot spark (about 40,000 volts to the spark
plugs) for quicker starts, smooth idle and more engine power, and is ideal
for use in other makes of engines because the parts are self-contained -
the ignition coil is located in the distributor cap and the control module
is located in the distributor itself. And there's only one 12 volt ignition
wire to operate to the HEI distributor. The HEI spark plug wires will be
needed, too. A Chevy V8 HEI distributor is shown to the right. The 4 and
6 cylinder ones are similar.
If there's not enough room or clearance on an engine for the HEI distributor, a smaller diameter non-computer controlled electronic ignition distributor from a Ford, Mercury or Lincoln, or Chrysler, Plymouth or Dodge (MOPAR) vehicle can be used instead. The Ford or MOPAR control module and ignition coil would need to be mounted elsewhere on the vehicle or equipment. And the spark plug wires that's made for these distributors will be needed. These type of distributors and ignition systems are also considered high performance.
How to fabricate it:
- Cut off the upper half of the old distributor housing and shaft (discard the upper half). Be sure to cut it close to the distributor head.
- Cut off the lower half of the HEI, Ford or MOPAR distributor housing and shaft (discard the lower half). Be sure to cut it far from the distributor head.
- Machine and adapt the housings of the lower part of the old distributor onto the upper half of the modern distributor head, and pin the two shafts together (like for shortened automotive axles). Click here for an explanation on how to pin two shafts together.
- Connect just one 12 volt wire from the ignition switch to the HEI distributor. And for the Ford or MOPAR ignition systems, connect the wiring as shown above in this web site for the control module and ignition coil.
- The firing order and ignition timing are set the same as for the old distributor/engine.
- It'll probably be a lot of work setting it all up, but it'll be worth it in the long run.
Fabricating a Killswitch - Top of page
The
easiest way to fabricate a killswitch circuit for a battery-ignition garden
tractor is to use a heavy-duty electrical (120v) 3-prong plug and a matching
3-prong receptacle, like the ones shown to the right. You'll also need about
4' of 14 gauge 2-wire double-insulated electrical wire. Although ordinary
lightweight "lamp cord" will work, double-insulated wire would be more durable
to prevent a short. Connect the wires so the ignition and electric fuel pump
circuits will be broken when the plug is pulled from the receptacle.
Here's
how to connect the wires:
- Inside the plug, connect the two flat terminals together with a short wire. Don't run any wires outside of it.
- Securely fasten a steel loop on the end of the plug. (A key ring works perfect.)
- On one of the [flat] terminals in the receptacle, connect the wire that comes from the ignition switch (positive side of the battery).
- On the other [flat] terminal in the receptacle, connect another wire that goes to the ignition system and electric fuel pump.
- Do not use the grounding terminal on the receptacle or plug. It's only purpose (as a killswitch) is to secure the plug in the receptacle and keep it from falling out when pulling.
- Fabricate a bracket to mount the receptacle on the rear of the tractor, just above the hitch.
- Route the wire in a safe manner so it will not get pinched or make contact with the ground or chassis of the tractor.
- Install the killswitch conveniently located just above to the pulling hitch within easy reach.
To fabricate a fool-proof killswitch for either a battery or magneto ignition system, fabricate one like what's in the drawing on the right.
-
For BATTERY ignition, use MTD's
safety switch part # 925-0268 or 725-0268 (normally open/black plunger).
Connect one terminal of the switch to the positive (+) ignition switch and
the other terminal to the positive (+) ignition coil terminal and electric
fuel pump (if equipped).
-
For MAGNETO ignition, use MTD's
safety switch part # 925-0269 or 725-0269 (normally
closed/red plunger). Connect one terminal
of the switch to the ground of the tractor and the other terminal to the
ground wire or terminal on the ignition coil or solid state ignition unit
on the engine.
-
If
you have a magneto ignition and an electric fuel pump, install two
separate switches in-line. A red switch to kill the engine (ground the ignition)
and a black switch to disable the fuel pump.
- Mount the switch(es) upside-down to prevent water and dust from entering into it/them.
- Use a long 1/8" diameter hairpin clip to hold the plunger(s) down. Return to top of page. È
Linked pages to my parts & services:
Please click HERE, e-mail me at pullingtractor@aol.com or call me at 1-573-875-4033 if you need machine work performed, repairs made, various parts, if your business would like to help sponsor my web sites or if you'd like to make a donation towards my web sites. Please call between 12 noon and 8:00 p.m. Central time, and please be patient because I stutter.
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