> > I'm not a fan of trying to reuse or repair an old camshaft
> > when you buy a new one for a six cylinder TR for approx $300.00,
> > manufactured with better materials & technology.
>
> Problem is, new parts are not always manufactured with better
> materials and
> technology. All too often, they are made in China or India,
> using inferior
> materials and non-existant quality control. That was exactly the point
> about the lifters, many new ones are unacceptably inferior.
I concur with Randall. I don't think the materials or technology involved
in making camshafts has evolved to any great extent in the last 50 years,
except in the application of CNC to the camshaft's machining and grinding.
Certainly, there is no reason to use any more exotic material than was
originally used, and the machining and grinding processes are the same. The
CNC aspect just makes the setup a little easier and the repeatability from
cam to cam better. The critical factor is the hardening of the lobes and
journals. I believe camshafts and crankshafts are case-hardened, which
means that the hardening only penetrates a small way into the material -
maybe only 0.010 - 0.015" in the case of a camshaft. The hardened surface
is then ground to the finished size. If the hardening is not done correctly
or the blank is not machined correctly before hardening, the case hardened
surface could be completely ground off in some areas, leading to premature
failure. This is what happened with the batch of bad lifters, I suspect.
A TR6 camshaft for $300 sounds really cheap to me, and I suspect it is that
cheap because it may have been made offshore. Caveat Emptor!
Michael Marr
Naperville, IL
1960 TR3A
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