Gearbox conundrum

[sam.bullen]

I have a 1962 948cc 2 door, and am putting in a 1275 Ital engine, mating it to the Minor gearbox. Question is, is the 948 'box the same as the 1098 one? My gearbox is ribbed, NOT smooth cased.

Thanks,

Sam

[liammonty]

A little confusing, as you're asking about the 948 box, but it sounds as though you have a 1098 box fitted.

To answer the easy part of your question, no. They are very different. Different cases – smooth (948) vs. ribbed (1098), different gear ratios, totally different synchro design (bronze cone vs. baulk ring) - the list goes on!

If you already have a ribbed case box fitted, I suspect your car also has a 1098 flywheel and clutch fitted to the engine.

[sam.bullen]

Thanks for your reply. My car has a 948cc engine, but a ribbed gearbox. Can I assume that because it is rubbed it is a 1098 box, and therefore will have a 1098 flywheel and clutch?

[simmitc]

You can assume anything. As above, we suspect that will be the case, but the only way to be certain is to look - peer in through the hole in the bell housing where the clutch fork would go if it was a left hand drive. There may be a grommet that can be removed. for access.

Is the engine definitely 948? Check the engine number and any casting markings, it was quite normal to swap a 948 engine and box together for their 1098 equivalents.

[sam.bullen]

Yes it is definitely a 948 engine (casting stamp) and it is also a ribbed gearbox. What is he easiest way to identify what size gearbox I have? The engine is now removed.

Thanks

[liammonty]

Well, you know that it categorically isn't the original 948 gearbox, as they were smooth-cased. It is most likely a 1098 one, but there is a chance it could be out of a 1098 or 1275 Spridget if I'm not mistaken - these were externally the same.

Ultimately, it doesn't really matter. What does matter is that the clutch and engine backplate combination is correct, and as mentioned above, a look through the holes in the side of the gearbox will enable you to tell whether you have a 948 or 1098 clutch fitted, which in turn will indicate which flywheel is on the engine. You can Google images of the 2 clutches, but the pressure plate on the 1098 clutch is much more domed, so it's easy enough to tell them apart.

Plenty of people have done the swap that you are doing, and I suspect one of them will give more advice on the combination of parts needed, as I've exhausted my knowledge now!

Edit: Doh - I see the engine is out - you'll be able to see the clutch fairly easily then!!