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Upright gearbox rebuild

Submitted by robert_maddock on Sun, 16/02/2020
Forums
Singles

Hello

I'm new to Norton singles and have a 1946 bought with the gearbox in pieces.  I have a few questions:

1)  I've just fitted new a new 'main gear wheel' bearing and layshaft LH bearing.  Both stand a little proud of the case but seem to be fully home in their housings?  Does this sound right?  (I realize I will know one way or the other if I assemble and check endfloat.)

2) The mainshaft RH bearing spacer (original?) is a fit through the threads for the clutch worm nut.  Is that correct that the worm nut pushes the spacer against the bearing?

3) is there a guide anywhere for assembly / timing the gear change camplate / selector forks?  I.E. reassembling the gearbox.

4) Finally, what oil should i use in teh box.  Manual says engine oil, but is gearbox oil (SAE80 or 90) better?

Thanks

Robert

Submitted by michael_sullivan on Sun, 16/02/2020

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You might not have noticed whether the old bearings stand a little proud as the new ones do.

If you have not throw away the old bearings, what are the identification marks on them and what are the identification marks on the new bearings?

If the new ones are wider, ask your bearing supplier if replacements are available with the same width as the old (original?) ones.

Mike

Thanks Mike.  The small bearing is exactly the same dimensions (surprisingly it is metric).  The large bearing (imperial units) is from RGM.  So dimensions should be correct.

Submitted by mark_zenor on Fri, 28/02/2020

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The internals, gears, shafts, camplate, selector is essentially the same as a AMC box. The rub comes on where to place the gear change quadrant assembly. It has to be engaged to the camplate to allow rotation between 1st to 4th gear selection. You can use the notch for 1st gear on camplate as a beginning point. That is the lowest point that the linkage will go. With nothing else in the box, loosely fit the lever to the quadrant and loosely fit the index plunger assembly and rotate through the index notches to see what the lever arc is. The Andover Norton parts list have a fairly good illustrated part diagrams, also. 

 


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