governor info needed,spark plug gap

535353m · Jul 19, 2018

looking for info on a belt driven governor,made in Chicago,ditt bros or similar four letter word. number D100 303. Also what does spark plug gap have to do with ignition? thanks,bought a tractor with big gap,plugs don't seem to be worn or burnt open.

mattofvinings · Jul 19, 2018

My free opinion is that the gap is one that can be reliably jumped by the delivered spark at max rpm, max load, wide open throttle. THe higher the combustion pressure the more voltage is required to jump the gap.

I think a slightly larger gap would give you a slightly larger flame front and possibly a faster burn in the chamber. But this is probably splitting hairs.

So, why doesn't a modern engine run like a 1/4" gap with its very high coil voltage? (seems like they run around .045 gap)

My opinion is that there is a sweet spot in the gap distance between having a stable spark and one that gets "blown out" of the gap by the swirl (mixture motion) in the combustion chamber.

Bob M · Jul 19, 2018

Have never heard of a Ditt governors. However Hoof has been supplying belt-driven governors for generations.

Punch the link for info on set up and adjustment Hoof (also Pierce) governors.

Unless you have electronic ignition, a plug gap 0.025 - 0.030 is normal.
belt driven governor instructions

rustred · Jul 19, 2018

just for the sake of gaps... oldsmobile ran .080 gap on plugs in the 1980's

governor info needed,spark plug gap

535353m

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