Scott,
To add to MJB's and Randall's excellent advise:
The pinion head bearing supplied by the factory was not off the shelf
Timken.
The later TR6 pinion depth was adjusted by a selective shim between the
pinion head and head inner bearing.
How do you know that the shims that were in the assy were correct?
The pinion drop distance is in the TR2/3 workshop manual, and there are a
number of ways to measure it. I used to go to the factory service school
to use their M84A (it was so expensive that the Bay Area dealers would
borrow it) I now have that tool and it is VERY Exact.
For reliability, and to not turn valuable horsepower into wasted heat, it
is important to follow the factory manual. Use only WD40 to lube the
bearings during assy and measuring. Checking the contact patch is essential,
but not as good as proper measurement first. Watch for anything that will
upset the bearings as they are fitted. Use the correct loctite on the ring
gear set screws.
This is the short version.
TR Regards,
Hardy
From: "Randall" <TR3driver@ca.rr.com>
To: "''Friends of Triumph' Triumph'" <fot@autox.team.net>
Subject: Re: [Fot] TR4 Pinion bearing assembly question
> Question - why is the outer race shimmed at the housing,
Stronger that way.
> If this is to position the pinion
> correctly fore/aft so that it lands correctly relative to the
> crown gear, I
> wouldn't think a few thou would make a difference.
It's the shims next to the pinion gear that set the gear position, and a
few thou does make a big difference.
> but with variations between the old and new
> bearings, I have no
> idea if this will result in the same spacing.
Reassemble the bearings you removed, measure the thickness, compare to the
new ones. Normally they will be exactly the same
thickness (but not always). I don't have the fancy tools, so I used a
Formica countertop as a surface plate, and a digital caliper
with a depth attachment to measure the height through the center of the
bearing. The "Made in India" carrier bearings weren't even
the same as each other, so I pitched them and bought some good Timken that
match the old ones exactly (within the accuracy of my
measuring setup).
Chances are that you won't want to reuse the old shims, they almost always
get damaged during the removal process. It doesn't seem
like a crease or two would make a difference, but it does.
After you think it's right, check the contact pattern.
Randall
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