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Dizzy Lash

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How critical is the gasket thickness between the distributor housing and the engine block. "The Book" seems to go into great detail about measuring the thickness of the gasket with a formula for setting the dizzy in place. The original builder of my engine just layed a smear of silicon down on the mating surface and cranked it down. I, in all my wisdom, hate straight silicon-smear-gaskets and decided that I needed a real gasket, with appropriate sealant. In doing this I am sure that I have backed the drive dog and gear out the thickness of said gasket. Seems to turn ok. Is lash setting here of such a great importance in engaging this spiral gear? There ain't a lot of room between the studs coming out of the engine and the pinch plate holding my dizzy in check. Trifles make perfection but perfection is no trifle. My OCD saying for the day.

Bill
 
Bill, that "gasket" is more of a shim to set the proper end float relationship between the distributor drive gear and the distributor shaft than it is a gasket to keep oil from flying around. If the end float is insufficient, thermal expansion alone could cause the distributor dog to bind on the drive gear. Too much can cause the drive gear to rise and play hob with your timing, and accelerate wear on the related components. It only takes a few minutes to set it right. (.003"-.007" if my memory is correct.)
You've gone this far doing things correctly, why fudge now? /ubbthreads/images/graemlins/nonono.gif
Jeff
 
If the manuals go into detail about setting it correctly it makes sense to follow the procedure.

I find it interesting that most LBCs use Lucas dizzys and don't specify setting this endfloat. Perhaps the problem isn't dizzy endfloat per se, but axial travel of the dizzy drive gear if the clearance isn't controlled. If the drive gear is free to move up and down this would indeed cause some timing scatter as Bugeye58 mentioned.
 
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