How much time

So far I like it & it runs good but I am curious if anyone has successfully used a timing light to adjust the ignition timing against the timing mark on the main case for maximum advance? When the magneto was in place I set the timing according to the impulse �snap� and the corresponding mark on the flywheel. This is an imprecise science at best! Maybe some of you pullers have some suggestions as to how much advance this engine will tolerate (?) (Stock cylinder head, aluminum hi compression pistons & electric start) Your thoughts, comments & quibbles please!

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Also thanks for reminding me of the mechanical advance, obviously setting the initial timing without considering this would cause too much total advance at governed speed.

This engine has aluminum pistons and I�m certain the compression ratio is above the stock cast iron slugs but is by no means excessive. I can attest that it is impossible to roll a piston through a compression stroke by hand without bleeding off some pressure! This was originally a hand start tractor that I installed a starter on so as to make it more user friendly as a snow-moving machine.

I was fretting about some form of degree wheel to set the timing. Thanks to you guys that paid attention in geometry class I learned that it�s already there, all it needs is a few marks of whiteout to complete it!

The ignition kit I used is a Pertronix from Genesee Products. I talked by telephone to a fellow named Andy at Genesee Products and asked a few questions. He put me straight and dissuaded me from using the ignition coil that I had in favor of using the kit that they offer that includes the ignition module and coil as a set. Glad I did - it saved me having to wire in a separate load resistor and all of the headaches the extra wiring can cause in the long term. The kit is simple. The ignition module inside (and under) the distributor cap is connected in parallel to the ignition coil by two wires. The tractor wiring provides power to the coil terminal in the same manner as with a breaker point system. That�s it.

NOW�.As soon as I find that timing light I�m on my way to being an expert on two cylinder electronic ignition.

One more thing�.You ain�t getting out without a story:

According to my (late) father, an �Expert� is any $@%&* fool more than 25 miles from home! (:>

Thanks for the help y�all!
daveo

To use the Left Hand Impulse flywheel mark to time, measure the flywheels outer circumference and divide by 360 to get how many radial inches per degree, and then measure off and make marks on it at maybe 20, 25, 30 and 35 degrees etc. BTDC. The Left Hand Impulse on the flywheel at 3 o clock in line with that flat mark on the side of the tractor is when the left piston is at TDC (both on compression and power), so make the marks startign there as 0 degrees. There was a great deal of discussion on here a while back about the modern DC powered timing lights and settigns for 2, 4, 6 or 8 cylinder etc. engines to make them accurate on our 2 cylinders, but all I have is an old fashioned self powered type and it works fine and needs no adjusting. When its on the left plug wire, it lights when it fires and shows me on the flywheel advance marks where I'm timed at.

As far as how much advance you can run, that depends upon the RPM, compression, fuel characteristics, valve dynamics and other variables. HOWEVER, as I have noted on here before, continued faster and faster timing advance is no fix or necessarily any help in horsepower gains (hurts if too fast). Its when you run extreme high RPM's (which our old JD's do not run at all) with high compression and high octane fuels etc. that advance becomes more important and critical, but in our old low RPM Deeres, too fast timing can cause more harm than good. Without knowing your RPM and compression and fuel etc., I still doubt that much any advance over 25 to 35 is what you end up at. If you have access to a dyno I would use it and then tweak the timing for the best results.

If you get her too fast at starting, it can be tough on starter drive assemblys (engine wants to kick back badly), so maybe you need to look at the advance on that distributor and get inputs from pullers on how they tweak that in.

To get full advantage of that ignition module, couple it with a high energy coil and run a wider plug gap for a wider, fatter (more surface area), hotter spark. Its high compression that requires more energy be discharged across the plug gap, but even at lower compression, a good hot high energy spark improves performance.

Good Luck n let us know where you end up at.

God Bless the USA

John T Nordhoff

Now that you're running a distributor you need a second person to hold the rotor at full advance while you turn the flywheel and note where the coil sparks. Timing lights are used very often but try to stay away from the fancy ones that have dial in advance knobs and other such tricky stuff on them - it gets confusing real quick.

Used to be a guy named Dave who posted quite a bit about his almost same setup as yours, only he had a high compression head (gas VS all fuel) added. He claimed 180 psi compression and severe pinging till he backed his distributor down to 18 degrees total advance at full speed. You can limit your advance by disassembly of the distributor and placing various sized sections of tubing over the limit pin found on the bottom of the advance weight's mechanisim. To get full advance in quicker, remove one of the springs.

I too just went with a Pertronix coil but am still stuck with points for lack of knowing which module number to order. Would you be so kind as to post that info? TIA. I _like_ my Pertronix 3 ohm coil, as a test I've now got my plugs set at .070 gap and she pounds it like a hammer. Pretty much stock except for .045 over cast iron pistons, maybe .070 gap is too much for high compression "A"? Used to stumble randomly when I loaded her real good, but not a sign of that since the Wico X broke on me and I went with a distributor and the Pertronix coil. What ever kind of 'goody' they pour into those coils is some pretty darn good stuff - this is the second one where I've noticed a night and day difference and I only own two of them, so far!