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Tech Question
Ricardo Maya, Monterrey, Mexico, 1976 Plymouth Duster 360
Hello guys. Please i need your help. I have a Comp XE268 cam in my 360-LA with stock heads, stock rockers, stock rocker shafts, and CompCams pushrods of 7.550" and lifters. The CompCams Lifters and pushrods have oiling hole. OEM and mopar performance do not have those holes. My engine, after 3000 RPM per periods of prolonged time it begins to have noise hard in the valve train. The oiling hole in the CompCams lifters and pushrods can be cause this noise? The engine does not have any noise at Idle rpm or before 2500 rpm. Thank you. Ricardo M.
Ric-
Having the holes / hollow pushrods will reduce the oil pressure some. Still, the top of the pushrods will effectively be blocked off by the rockers, so I think this is unlikely, especially since you say it is noisy at higher RPM -- it would be the opposite if this were the problem.
Did this problem just suddenly happen, or did it begin after the engine was modified or assembled? Anyway, here's some things to check:
> Adequate oil pressure at the "noisy" RPM - at least 40 PSI
> Were the rocker shafts installed correctly (notch at front on left, towards rear on right, and pointing directly at crankshaft)?
> Are the lifters preloaded something between 0.030 and 0.180"?
> Was the cam broken in properly (no idling for the first 20 minutes)?
Rick
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