> "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.
On a related tangent, I vaguely remember reading years ago of an engineering
analysis of a 1/4 mile drag race motor that said it was flat-out impossible.
Almost every component was being stressed beyond it's limits ... and the nitro
was already burning when it came out of the supercharger. The analysis was
apparently correct but obviously wrong ... I didn't hear the rest of the story
presumably about how the engineering models were updated to cover the observed
facts. Including the fact that an all-out drag motor is only expected to last
for a few hundred revolutions !
> 5. Is there anything wrong with just making the lifters out of good
> steel and heat treating it to, say, Rockwell C 56 - 60?"
Probably not, as long as you define "good steel" to mean "steel that will make
lifters that work" <G>
Jack, I'm very interested in the answers from your engine engineer. But as a
professional engineer myself, I'm all too aware that engineers don't always have
the right answers. Ultimately, all engineering boils down to "We did this and
it worked, but when we did that it didn't work." Stories like the one above are
all too common.
And as I've tried to illustrate, the questions are almost impossibly vague. Yes
of course there is something "wrong" with making lifters in any way imaginable.
The real question of course is "are there any conditions under which this might
be an acceptable compromise" and then of course one has to define what is an
acceptable compromise and so on. I read engine construction articles all the
time that don't even bother to harden the lifters ... but those engines turn
only a few hundred rpm and then only for exhibition at little or no load.
Randall
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