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MG Midget and Sprite Technical - 1500 gearbox syncro rings

I had my 1500 gearbox rebuilt a couple of years ago with new bearings, syncros etc. From the start the 2nd gear syncro was weak and the box was sent back under warrenty. The chap showed me the new syncros he had fitted, and how they were bottoming out before the cones fully engaged. Poor quality replacement parts. I *think* he got them from Moss.

The box was built with another new set of syncro rings, and two years later the 2nd has completely gone and 3rd is weak :(

Over the next few weeks I'll take the engine and box out of the car and replace the syncros myself. Can anyone point me to a good quality source of syncro rings? NOS maybe? Or tell me which ones to avoid.

Chris Madge

Chris
You could try contacting Hardy Engineering Transmissions to see if they can supply you with parts and maybe offer advice. I'd thought of Heathrow Transmissions also but they only do A series g/boxes.
Bill Bretherton

when i rebuilt mine i had been warned that the quality of new ones was poor so i bought a low mileage box and made a good one from both the worn ones were 1st and 2nd gear, it may be worth speaking to someone like Heathrow Transmissions for a good source of parts.
mark heyworth

Thank you both. I'll speak to some of the Gearbox companies and see what they say.
Chris Madge

I think I have some second hand but "original" synchros in a box somewhere. Happy to donate these to the project, to use or to compare with reproduction units.

Malc.
Malcolm

Rimmer bros. used to be the place to go for good Triumph parts but I guess they will all source from the same supplier these days.

But I wonder if there is an oil spec issue with the short synchro life, Chris?
GuyW

The more research I do into this, the more I hear about problems with new synchro rings. Often the internal dia is too big and the cones don’t engage properly.

A guy in the states has ended up making forged ones, with a carbon friction surface, as the modern parts weren’t lasting more than a couple of races in his Spitfire.

Guy - I used the oil spec in the owners hand book. The first time I used a Halfords Comma oil, the second time I used Millers brand. I’m confident it was the right oil.

Malcolm - that’s very kind of you. Yes please, I would gladly pay for them.
Chris Madge

It's not just Spitfire synchros. When I converted to the Datsun gearbox , I had it rebuilt it using a rebuild kit. The guy who did it for me said that the synchros would be noisy but I had them put in anyway. Every time I shifted from first to second it would grind. First and third weren't silent either. I finally put the originals back in and it has been silent ever since. Yes, bad part are common across the whole spectrum of replacement part.
Martin

Hi Chris,

I had a look for said spare rings yesterday. I can't find them so must have cleared them out after the last time I did a gearbox and thought "never again!". Sorry mate.

Cheers,
Malc.

Malcolm

No problem, thanks for looking Malcolm
Chris Madge

I have lost all confidence in new reproduction parts for our cars, and I dont fancy taking a gamble on used ones to have to replace the syncro rings again shortly after.

I talked to the chap in the US and eventually bought 2 of his forged syncros with carbon friction surface hes made for racing. At $85 each they are expensive !

I figured I only ever use first for pulling away and the existing ring seems fine. Fourth is easy on syncros, and at the moment seems fine. (I also have some spare used rings to pick the best from when i rebuild the box)

The new rings will go on 2nd and 3rd where they are needed most. Probably overkill for a road car, but hopefully ill be able to drive the car to its full potential rather than nurse each gear change!

It will be another week or so before i take the engine out of the car and start on the gearbox. Ill update once its done.....


Chris Madge

Ooooo! Fancy fancy! I hope they work well for you.
Malcolm

Nice Chris---Do you have to run ATF with them-----
Just curious
willy
William Revit

William - good question, I’m glad you asked. I don’t know, I need to speak to the seller.
Chris Madge

Chris--It was just out of interest,-the reason being, when the T5 gearboxes came out it was drummed into everyone that they had to run on atf because of the synchro rings having the fibre inserts/lining, but strangely , later on the boxes were used on V8s and turbo 6's and they changed to 75/90 gearoil with no change to the rings---always intrigued me after all the hype over using atf only----It'll be interesting to hear what your supplier comes back with-----
willy
William Revit

Willy,
why would this bloke know, the car manufacturers never seemed to know and change their minds about what oil should or must(!) be used including BL and of course your favourite and not mine VW, despite their German engineering 'quality'.

Some people over here used to put ATF in the LR and Ford boxes and AFAIK it was never very successful in car use, be alright as a limited use flush clean I expect.

Nigel Atkins

Chap says the original Triumph 1500 gearbox spec oil is fine.
Chris Madge

This thread was discussed between 21/04/2022 and 07/05/2022

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