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Chances of rebuilding a 12G333?

Posted: Fri Dec 06, 2013 12:07 am
by Benny
This is a long way off, but that doesn't stop me thinking about these sort of things....

My Cooper 'S' came with a pair of 12G333 transmissons....one with straight cut gears and Hardy Spicer outputs, the other with helical gears, and yoke outputs, so there isn't much common hardware between them. Both transmissions were left open and u protected for 20+ in a garage near the coast, so there is a moderate (not too bad) coating of surface rust on all of the gears.

If the transmissions shared more hardware, I would be confiden that one could be canibalized to help rebuild the other one. But, with my current situation, I'm wondering wha the chances are of bei g able to salvage these transmissions? Are good, used parts still out there? Are any new parts still being produced?

Thanks.

Re: Chances of rebuilding a 12G333?

Posted: Fri Dec 06, 2013 2:09 pm
by CooperTune
Having built the 333 in both SC and std. and building trannys of all types these days I see no reason you can't rebuild one or both. Having two is a bonus. I'd start by stripping each and boxing all parts seperate. I use a buzz pen to number the case , diff. cover, diff side covers and the speedo housing. If you were lucky enough to get the drop gear/clutch housing with each keep them together with the other parts. Inspect the idler bearing bore and the idler thrust face for damage. It's always a good idea to inspect the drain plug threads. Much easier to helicoil in a milling machine than in the car once done. Having some time before needing one I'd start looking for shift forks. It would be nice to locate some NOS forks. I'm not sure about three synchro but I have had some issues with four synchro remote forks that are aftermarket. Check with Nick Swift and see if he has any high quality lay shafts made. Close inspection of the third motion shaft spigot. The first /second shift hub as well as the third /fourth shift hubs are the same from both. First gear is the same also. The first/reverse teeth on the lay gear is often a wear area. Given time and effort you should be able to find everything you need NOS. I have several 333s stripped cleaned gears corn cob blasted lubed and stored. The last few Cooper S power units I have built ended up with 22A1128 four synchro S ratios. If you drive much and run a 3.1/2.95 or 2.76 CWP being able to slip back into first without a crunch is nice. For my next trick I'm going to try and install a set of A+ gears in a 1128 with a magic wand diff. cover. Steve (CTR)

Re: Chances of rebuilding a 12G333?

Posted: Fri Dec 06, 2013 3:14 pm
by Richspec
For my next trick I'm going to try and install a set of A+ gears in a 1128 with a magic wand diff. cover. Steve (CTR)


thats what guessworks does, and thats what under my 8 port.

Re: Chances of rebuilding a 12G333?

Posted: Fri Dec 06, 2013 4:17 pm
by Vegard
I prefer to stay away from crappy A+ gears with even more crappy ratios.

Re: Chances of rebuilding a 12G333?

Posted: Sat Dec 07, 2013 4:33 am
by Benny
Steve,

Thanks for the feedback. I suppose I should start keeping an eye out for some bits. What are your thoughts on the coating of surface rust on the gears?

The gearbox in my Land Rover was full of water for 25 years, and the gears looked like scrap, but with some clean-up effort, a few of them actually look usable. The gears in my 12G333's are nowhere near that level, but with them sharing engine oil, I wouldn't want to take any chances.