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Posted by Matt Wilson [71.170.81.50] on Saturday, January 21, 2012 at 11:35:06 :
My engine manual states that the tappet-to-bore clearance should be 0.0000 - 0.001" with a wear limit of 0.0015". The manual is an Army manual, TM 9-1840A/TO 19-75B-15, "Ordnance Maintenance Engine and Clutch" published in 1952. Why would they specify 0.0000" as the lower limit? It would seem to be a bad idea for anyone to set up their tappets with no clearance. Maybe it has to do with the manual's recommended method of measurement (dial indicator)?
For other (more modern) engines, the general consensus is that anything less than 0.001" is asking for trouble, and it's preferred to be between 0.001" and 0.0025", depending on who you ask, and depending on whether flat tappets or roller lifters are used. Mind you, this is for lifters with diameters around 0.8" - 0.9", whereas the 230 flathead six tappets are smaller at approx. 0.624" in diameter.
Does anyone have a different manual for this engine with specs for this clearance, and if so, could you post what your manual states?
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