Ok, so ive got my gearbox in pieces, ive fitted a centeral pickup and put the laygears back in all no problems, and started to put my 2.9 diff in, the problem is that the 2.9 pinion is signicantly larger than the 3.44 pinion. so while it is fitted to the shaft, and i have done up the bolt(yes, very very tight...) the bearing retainer is to small, the hole in it isint much bigger than the 3.44 pinion, and it just will not go on over the 2.9. what do i do? do i just leave it off? i can still fit the retainer for the lay and reverse shafts.
any suggestions?

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speed costs....how fast do you want to go...

Did you get the bearing retainer with the diff? They are different sizes for different ratios. You can use the standard cover, but you will have to grind or file out the inside to clear the pinion. From what I know after fitting a 3.1, is that you need to install the retainer, Try giving Steve at brickworx a call on 0882979494. He may have a retainer from a 2.9 or 3.1. The 3.1 may still need work, but it will be far less than the 3.44.

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1275 LS Brisbane

You MUST fit the retainer. If you don't the mainshaft will tend to pull itself and the bearing out of the housing due to the reaction from the helical cut final drive gears. Can't remember which way the helical direction is. If its OK going forward it will try and pull itself from the housing when you go backwards or vica versa.

Regards
RonR

If you have a lathe it's pretty easy to machine it for the bigger pinion. beats grinding...

As miniron said, DON'T leave it out!!!

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks all for the quick reply, i dont have the 2.9 retainer, so i will try and track one down. thanks again.

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speed costs....how fast do you want to go...

i really can`t understand why you`d want to fit a 2.9 ratio anyways,,,the car will become a pig to drive as it will not have any grunt in the taller gears & will probly not be able to rev past 4500rpms in top gear.

I mean it`s your car & i`m not going to tell you to do things, but when such a tall final drive ratio is fitted, they just become boggy dohy pigs with no grunt,,,first gear might "feel" great, 2nd will be ok, but 3rd gear becomes a struggle & 4th is just hopeless

Hope you have a 1400-1500cc engine to pull such tall gears, cause if you have a 998-1100, then it`s even more of a dead power curve

YUK!!!

sorry, but just my theory & practise experience warning you

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Half round file and a bit of elbow grease is all you need. The retainer metal isn't very hard..

Cheers, Ian

The problem here is you are probably trying to fit the 2.9FD to a remote type gearbox. These 2.9s were designed for the rod change boxes that had a greater bore in the double roller bearing retainer than the remote type. You just need to grind the centre out of the retainer to clear the pinion. BUT... I hope you are not going to be giving this motor a pasting... the retainer may well break under the strain. KC.

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Tuning should always be a compromise between what is possible and what is necessary.
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