This is a really interesting subject to me. We all have opinions on
this subject, but I doubt that any of us have real life experience
designing cams / lifters, evaluating failures, dealing with the
metallurgical processes, etc.
I'm going to try to find somebody who actually knows -- heavens
knows, I rely on old wives (in this case mechanics') tales and what
companies who have a profit motive say about it. I do know one guy
who is engine engineering with a major engine manufacturing company.
I'm going to ask him to help us gain a better understanding.
Following is the beginnings of a message I'm going to send him, and
I'm asking folks on this list who are interested to read my proposed
message and contribute any other questions they can think of that I
should ask at the same time. Here it is so far:
"Somewhere back in the dusty corners of my memory is a sequence of
events that took place with an engine manufacturer --- a rash of
camshaft failures, subsequent investigation, subsequent findings
-- Seems that the lifters were hard enough, all right, but in the
heat treating process the metallurgical crystals all ended up
oriented such that the face of the lifter was like a bundle of
pointed ice picks against the cam lobe.
Sooooooooo............I have a series of questions, and they really
should be answered by someone who knows, rather than us folks who
currently rely on opinions:
1. Should old lifters remain with old lobes?
2. Is it ever acceptable to use old lifters on a new cam? How about
new lifters on an old cam?
3. Is there any reason why an old lifter can't be reground to the
proper radius and reused?
4. Is Rockwell C hardness the only criteria for successful lifter life?
5. Is there anything wrong with just making the lifters out of good
steel and heat treating it to, say, Rockwell C 56 - 60?"
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