A question I had put to me has fermented another question in my mind...

Can anyone tell me why Mk1 Cooper S boxes had the 22G333 case numbers? The cases are identical to the deluxe 3speed synchro boxes, so why did they need a special designation for common sized internals.
I can't see them making special casting runs for simply a change of ratios on there own....

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Good to see I got your brain juices brewing.

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Its mostly bubbles Scott...bubbles and froth.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I have not 'side-by-side' compared them however I'd say it has to do with the extra clearance needed for the longer stoke and bulkier big ends on the rods for the 1275 vs 998 as the '333' box was introduced with the 1275 (and 970) S.

<EDIT> Just checked. Yeap, that is the difference.

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So where do morry 1100 boxes differ? I've heard they run em in Nb, where you need 3 synchro boxes?

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Although they have a longer stroke, the Big End of the Con Rods is not as bulky.

You can grind the case to work on a 1275 as '333' cases are not easy come by.

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M1100 boxes also have the extra clearence for the longer stroke crank, thats why we use them on the go faster engines.

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What's the casting number on them? Got it handy? Was it also the same one they used on the 1100S?

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Ah, got it. They were a 22A1128 (not to be confused with the 22G1128 all synchro), for the 1100 and 1100S. As these were later than the '333' and they were mated to 1275 engines, there is the answer. It is a different case to the Deluxe. Also had a slightly different diff cap.

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The Cooper S was built to race so I think it may have been for homolgation reasons

Late Cooper S Mk1's also used the 22A1128 case from the factory. I think the other serial number on the case commenced with 12FA.

nup, not 22A1128, it's 22A1288 - and yes, it was the 'commonised' long stroke 3 synchro 'box. I have a couple of them from liberated 1100 S motors

I think standard 1100's used 22G68, at least in the early days, which were common to UK Coopers

Yep my 1100S has the 22A1288 box on it, I've also seen early 1100S engines with 333 casings but with the sandwich mount for the remote extension as per normal 1100. Had one case I sold to a guy in NZ to use in an S.

cheers

Jacob

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'72 Clubman Van - 1022cc, 295 head, 731 cam - Daily Driver
'69 Morris 1100 S - Dinged by a bus, in shed under repair
'64 Morris 1100 - Early 1100, long term project

race guys use 3-syncro boxes because the close ratio straight cut gear kit is a closer ratio gear kit than the 4-syncro straight cut gear kit

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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.

And if its an Nb car we are not allowed to use 4 syc boxes as they were not available in a Mk 1 S.

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