Hello all,
I have an engine problem that I wonder if any of you have experienced or if
anyone has any suggestions as to what it might be.
I was sitting at a stoplight this morning and all of the sudden the engine
starting making a loud tapping noise at idle. Had it towed home and
diagnosed the following.
I thought that maybe a valve spring had broken or a rocker arm had broken or
somthing like that, but on pulling the valve cover off, everything seems ok.
With the engine running with the valve cover off, all of the valves,
pushrods and rocker arms are all moving nicely. Lots of oil getting
splashed around as well.
I pulled the spark plugs leads off one at a time and other then a slight RPM
decrease, no change in the noise. With the cylinder not firing, I would
have thought if it were a connecting rod bearing or wrist pin, the noise
would have stopped or changed.
The noise is definately louder with the valve cover off than with it on, and
sounds like it is coming from the top of the engine. It is a loud tapping
that changes directly with RPM. It is not a deep knock like a con rod
bearing would be; It is a much lighter tapping.
It almost sounds like a valve hitting the piston; maybe the timing chain
jumped a few teeth? Other than the tapping, the engine runs smoothly and
starts fine. I am trying not to run it any more than I have to to diagnose
it as I don't want to cause more damage; whatever it is.
Any ideas?
Thanks,
Frank
'65 BJ8
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