Hi Jim,
Thanks for the info. I was unaware there were other hardness tests un
use for our cams and lifters.
I couldn't help noticing that you have a Damask Red MG. I have a BMH MGB
Body Shell and am trying to decide on color. I've just got back from a
car show and saw some Damask Red MGB's and they did not look like the
pictures I have seen on the web.
https://home.attbi.com/~justbrits2/gary.html
http://www.teglerizer.com/mgcolors/index.html
I you have some photos of your Damask Red MG, I would be interested in
seeing them.
Thanks,
Don Malling
James H. Nazarian, Ph.D. wrote:
> Don Malling wrote:
>
>
>>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.
>
>
> Although somewhat more expensive to purchase than a Rockwell Hardness Tester,
>a
> microhardness tester is the instrument of choice for non-destructive harness
> testing. It uses either a Vickers (square cut) diamond, or better yet a Knoop
> (oblong 1:7) diamond indenter instead of Rockwell's steel ball to make a
> microscopically small indent. The dimensions of the indent are measured using
>the
> built in microscope, and are so small that when done properly, the tested item
> can be returned to service as is.
>
> Jim (the dad)
> microdoc@zoominternet.net
> 1960 MGA 1600 Very Red
> 1974 MGB-GT Damask (Very Burgundy) Red
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