3,63 Stanpart crown and pinion in a Herald diff?

[Roger]

I need some advice from the brain thrust again…

I noticed that new ”Stanpart” crown wheels and pinions are available. Not sure if this is a new thing or if they have been available for a long time? I have been trying to source a 3,63:1 Spitfire 1500 diff for my Vitesse in Sweden for a long time, but no joy. As some of you might know by now, shipping costs are an issue for me when buying second hand parts. It’s a long way to the Åland Island. I have two diffs in my possession. One 4,11:1 from my 1969 13/60 and one 3,89:1 in my 1966 Vitesse. Would it be possible to convert my 4,11 Herald diff to 3,63:1 by ordering the ”Stanpart” 3,63 pinion and gear? These parts are expensive, it would be frustrating to order them and later find out that they do not fit in my 13/60 differential.

[johny]

One problem I can see straight away is that the splines are different. For cost savings Triumph later went to rolled fine splines for many drives (gearbox, clutch and diff) in place of machined ones. This means you would need the later coupling however I have a feeling theres other issues as well....

[JumpingFrog]

There are two different diameters of pinions, Herald, early Spitfire (pre Mk. IV) and Vitesse 1600 are smaller. As such the bores for the bearings in the front of the diff housing are also smaller. Converting the 3.89 will be possible, the 3.63 pinion will fit, but converting the 4.11 won't be easily possible without machining the casing.

Edited March 4 by JumpingFrog

[Pete Lewis]

and dont ignore the accurate dimensional mounting distance  settings you need to have to correctly mesh and shims to  preload the gear sets

not for  the faint hearted unless you want to make a real whiner 

Pete