Hello All,
Managed to diagnose the rough running 72 RR 3.5 v8 engine, I took the rocker
covers off and ran the motor. It appears the a couple of the valves are
not opening, this is accompanied by much heavy tapping. I am not sure if
the valve is inlet or exhaust, but the rocker hardly moves. There is very
little oil coming out of the valve area. I initially suspected lifter
leak down, but whilst rotating the engine and feeling the pushrod there was
no slackness at all. To me this points to a very badly worn cam shaft.
So my questions are:
Can lifter leakdown cause a valve not to open?
Should I see any oil coming out of the rocker shaft.
I checked the bottom end and it appears to have been rebuilt, is there
anything that can cause a cam to wear out quickly.
At this stage I am tossing up whether to look around for a 2nd hand motor
cheap or put a new cam in this one. I am a bit concerned about this engine
as it seems to have very low compresssion, ie about 70psi in a couple of
the cylinders, possibly due to the non opening valves, but could be broken
rings. I guess it is also possible that the rings have simply "STuck" after
such a about 4 years of storage with very dirty oil....
Regards
Stuart
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