> The fact that the crank shaft is steel and
> meshes with aluminum does not bode well for long life,
IMO this misconception is the cause of a lot of problems with the original
seal.
In "normal operation", the crank should never touch the seal, so the seal
should never wear out. But, what happens is that the main bearings wear,
which allows the crank to move around and so touch the seal surface. When
that happens, the aluminum seal must be replaced. But, since it's never
_supposed_ to wear out, replacing it is not considered a normal part of a
rebuild ... thus everyone is running around with worn-out, original seals.
The problem is apparently compounded by some vendors selling seal mandrels
(the tool that should be used when installing the original seal) that are
not made properly, resulting in improper installation, and a worn seal that
never seals correctly again (even if it was only run for a few miles).
The last problem of course is that the original seal does not resist
pressure in the crankcase very well. For old, worn out engines, there can
be considerable pressure in the crankcase from blow-by, even on the TR2/3
with that big road draft tube. For the later cars with various emission
control arrangements, the pressure can be even higher.
But given that for many engines in the 50's, it was not uncommon to have to
replace the rear seal every 30,000 miles or so, IMO the original design was
actually a very good solution to a tough problem.
Randall
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