timing IHC magneto to a TD6 which starts on gasoline

ejensen · Mar 18, 2017

Years ago I removed the IHC magneto from my 1952 TD 6 , which starts on gasoline, and installed a distributor with solid state ignition. Still have the magneto as a back up. I think to time the magneto to the engine I did the following: brought the engine up to TDC on the compression stroke, turned the magneto from the coupling CCW until the rotor was pointing at number one cylinder. Installed the magneto on the engine at this point.

Is this correct? I didn't turn it through impulse for number one cylinder

SW EM · Mar 18, 2017

Yes, you have the right idea. The impulse should click at the correct TDC timing mark on the crankshaft pulley. Verify that the number one cylinder is firing on the correct stroke when you have it installed. You probably also know that the magneto turns the opposite direction as a regular gas M magneto.

ejensen · Mar 19, 2017

SW EM
Yes the magneto turns opposite direction to a regular gas magneto.

I install the magneto before it impulses for TDC cylinder one. It will impulse when the engine rolls through TDCon the compression stroke for number one. I know the impulse provides a hot spark, I think, but does this also provide a retard when starting?

SW EM · Mar 20, 2017

Assuming the implulse trips exactly at or slightly after TDC (the latter being on the safe side for hand cranking).... once the engine is turning fast enough for the impluse to quit catching (around 300 rpm iirc) the magneto will advance and the advance angle is 15 degrees I think.

To answer your question, yes the impulse provides the spark retardation while cranking the motor.

ejensen · Apr 17, 2017

SW EM,
Another opinion of mine: Impulse causes the magneto to move quickly through the magnetic field causing a hotter spark equivalent to spark when magneto is turning at normal speed is this correct.

When working on the magneto used on a D2 starting engine seems to me that the magneto, 'magneto built by Fairbanks morse for the caterpillar tractor company" didn't have impulse. This particular 2 cylinder pony gas engine used a rope for starting.

Would like to know if you agree with my thinking about the impulse which is part of the magneto used on the gas starting side of my TD6. Had a wico magneto for the TD 6. It had ipulse.

timing IHC magneto to a TD6 which starts on gasoline

ejensen

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SW EM

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ejensen

Well-known Member

SW EM

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ejensen

Well-known Member

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