Crankshaft wobble

[Tony Press]

Presumably those suggesting a face to face assembly have tried this in an Austin Seven and can vouch that it does not cause problems?

What problems can you envisage ?

The bearings are still a pair so radial load is not compromised, the clutch axial thrust is still taken by one bearing - the inner bearing in one case, the outer bearing in the other, both working through the front plate.

Providing the bearings have standard width outer rings the housing depth is the same either way.

The only difference would be the nose of the crankshaft is allowed some slight movement without unduly stressing the bearings under crankshaft whip. 

I am not aware of any factory instruction about fitting the angular contact or 'double purpose' bearings other than the August September 1936 Service journal - page 124. Of course the 1936 on reduced width outer ring bearings must always be fitted back to back.

I would think the face to face assembly would cause less problems than the suggestion of fitting a self aligning bearing at the flywheel end, or deep groove ball bearing or bearings at the front.

I cannot quote the result of anyone knowingly using bearings in the face to face configuration.

Simon,

You wrote- "on checking the bearings I have, the centre rings project more one side than the other, presumably having been ground to generate the preloading, with the bearings fitted back to back.  (Of course, you idiot Harding!)
This projection means there is a space between the outers, if put together the "wrong" way round, of 75 to 100 thou."

If the outer rings of your AC bearings are 1/32" narrower than the inner they are post 1936 pair and must be installed back to back - check the housing depth is 1 9/16" (vs 1 5/8" for the standard bearings)   

Tony.

Tony, just rereading this thread as I want to preload my AC bearings, the main downside with face to face is that you are relying on the front lip to preload the bearings, and restrain the outer tracks 
In use, whereas back to back the starter dog is providing the preload and holds it all together.

Does anyone do shims to put between the outer tracks.

Rgds Gene

Gene,

The preload (if thought required) should be two thou. which the front plate will be able to accept if face to face fitting is used.

It is quite difficult to measure the required shim thickness on the bench with an unmatched pair of angular contact bearings and this won't allow for inner ring expansion when mounted.

Cheers, Tony.