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MG Midget and Sprite Technical - 1500 gearbox rebuild

I am rebuilding a 1500 gearbox out of 2 boxes i have when i dismantled them both the syncro ring in both are very good but one set look new the others are from a low milage box i am not sure which to fit as I have heard bad reports on them.

mark heyworth

and the ones i think are new

mark heyworth

Mark-
Best way to choose is-
Sit the ring on the taper of the gear, and acurately measure the gap between the back of the ring and the synchro teeth on the gear--then try your other ring and remeasure
The synchro measuring the widest gap is the best one to use-----

willy
William Revit

It is a bit tricky to see from the photos if there is much difference in those rings, but the concentric grooves should be sharp and well defined.

Should you be swapping synchros between boxes? I thought it was best to keep used sychros with their gears as they wear to match somewhat.

I enjoy a good gearbox rebuild. Probably more so than an engine build.
Malcolm Le Chevalier

This page is a good reference for when you haven't taken enough disassembly photos and discusses the synchro issue a bit.

http://joeblogs.eu/2017/03/30/spitfire-1500-gearbox-rebuild/

Malcolm Le Chevalier

never having done a gearbox before is this the correct way to check bush end float measures 0.10mm .

mark heyworth

I can't remember off the top of my head. The workshop manual is really useful on this. I can take pictures of the appropriate pages if you would like.

Having a clock gauge is a good start at least! :-)

Malc.

Edit: Also, you might be limited in what you can still get in terms of bushes, shims etc. so might have to live with end floats that are less than ideal specs.
Malcolm Le Chevalier

says 0.101mm to 0.152mm so i would think its close enough

mark heyworth

This thread was discussed between 19/11/2018 and 22/11/2018

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