Fellow SOLers
I am hoping that some of the mavins on this list can help me with a problem
concerning my 70 TR-6. The question I have concerns the aftermarket cam lifters
available for the TR-6 engine. I have heard rumors that some of these lifters
are not hardened and are thus prone to destroying themselves and the cam.
The reason I am worried is that I have modified my engine extensively to
increase the performance, by shaving the head to give 10:1 compression and also
porting and polishing the intate and exhaust ports. In addition I also shaved
the intake valve stems to remove the excess metal, balanced the crank shaft,
etc,etc. The real problem, which directly relates to the cam lifters, is that I
also had the stock cam reground to a hotter profile (more lift, longer
durations) and installed double spring, valve springs which have 105 lb of
pressure instead of the stock 40 lb to reduce valve lash at high RPMs.
This engine is sitting ready to go in a car which has just undergone a 2 year
nut and bolt frame off restoration. I now wonder whether it is a time bomb
waitng to self destruct.
What should I do? Doe I tear the head off this engine and have the lifters
tested? If so how can the lifters be tested for hardness without destroying
them? How hard should they be? I can get no information from the supplier on
this question.
Do I trash the lifters and by a different set? If so how do I make sure that
the new set is properly hardened? One possibility that was suggested to me is
to remove the inner of the two valve springs before starting the engine for the
first time and then run the engine for 20 minutes at approx 2000RPM and then
replace the spring. While this may help reduce the chances of a lifter failure
I am not sure this will do anything to aleviate the problem for the long run.
Any information or experience with this problem will be much appreciated.
p.s. Am I just paranoid or am I suffering from some variation of the numerous
diseases which befall british car owners.
Kevin A. Strait, Ph.D.
Assistant Professor of Medicine email: strai001@maroon.tc.umn.edu
and Cell Biology/Neuroanatomy
University of Minnesota
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