Found this when I was searching the 'net trying to find out what the hell
"brinelling" is:
http://www.timken.com/products/bearings/services/valueadd/prevent.asp
bs
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Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
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-------------- Original message ----------------------
From: jerry adams <cjerryadams@yahoo.com>
> List,
>
> Just to add to what Steve said. Donald and Geoff were good well grounded
> engineers with lots of practial and racing R & D. The BN1 had ball bearing
>type
> front wheel bearings and probably had stub axel or bearing failures which
>cause
> them to go the Timken tapered roller bearing for the front. Since the front
> wheels and axels receive a lot of both radial and axial loads I can
>understand
> why the Timken tapered roller bering was selected. For these bearings to
> preform as designed the must have preload so that the races are not damaged
>from
> shock loads during driving. The ideal preload would be exactly 0 lbs, so
>that
> the bearing would not move during any axial load since the cars weight has
> already loaded the radial load. (Actually the Timken design has both radial
>and
> axial loading built in when the bearing is install and weight is put on the
> bearing, with 0 lbs. preload).
> The distance piece and the shims were added to give the bearings as colse
>to 0
> lbs of preload as possible. In actual practice you can't get 0 lbs unless
>you
> are very lucky, so the next best thing is to try for a few ozs. of preload.
>A
> few ozs. of positive preload is better than a slightly negative preload,
>since
> the negitive preload will give you some slack and cause some small load shock
> during axial loading. Too much preload will cause brinelling and premature
> bearing failure.
> When installing the bearings and setting up preload, set up with light oil
>on
> the bearings and without the grease seal, some say set up the bearings dry.
> After preload is set then grease bearings and install grease seal. This is a
> lot of work but should be done right.
>
> Jerry
> BN2
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