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Rockwell Hardness Testing -- Cams and Lifters

To: 6-Pack <6pack@autox.team.net>, "mgs@autox.team.net"
Subject: Rockwell Hardness Testing -- Cams and Lifters
From: Don Malling <dmallin@attglobal.net>
Date: Thu, 12 Jun 2003 21:15:34 -0400
There were some questions about how Cams and Lifters were hardness 
tested, so I asked Steve Gruenwald, owner of Integral Cams, how they did 
it.

His reply:

Dear Don:

We use a Rockwell hardness tester to hardness test the lifters.  It 
creates a small pin mark in the lifter face.  When we regrind the 
lifters sometimes this pin mark cleans up before the other wear marks 
and sometimes not.  It depends on how bad the lifters are worn. 
Rockwell hardness checking is generally classified under "destructive 
testing" but its not literally that brutal and in this case it only 
means that the part can't be used "as is" after testing.  We certainly 
would not want to hardness check the lifters after grinding and 
polishing them because the little pin mark would cause rapid cam and 
lifter wear in an engine.  So the only bad thing about this testing 
method is that we can't test an already new set of lifters without 
having to regrind and polish them afterwards.  Another question I am 
often asked is:  when we regrind the lifters to make the pin mark go 
away, are we grinding off the hardness layer and will the lifter now be 
soft?  The lifters are chill cast which has a broad diffused hardness 
band so we don't have to worry about instantly grinding through the 
hardness band like you would if the lifters were induction hardened.

Please let  me know how you like your cam.

Thanks,
Steve Gruenwald
Integral Cams

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