Cracked engine backplate

Well, what I meant to say was, I know it's weldable but will it distort, or cause other stresses and cracks? If there's the slightest distortion I won't keep oil in the engine.

I'd try the Mini specialists like Minispares for a s/h one first or subscribe to some A series forums online. There must be thousands of those knocking about still. If you weld it it may well distort and at best you'll have to have the welds ground back flat. Doesn't sound the easiest or cheapest of jobs.

Dave Baker - Puma Race Engines

Don't think it's machined - simply made out of sheet, or plate, steel which has been rolled in manufacture.

I'd say so as much as any steel.

Wonder why it cracked?

Should be easy enough to get - same part as Morris 1000 and A40.

To repair you would have to drill hole at the growing end of the crack grind a "V" along the line of the crack with an angle grinder (from both sides would be best) clamp it up properly and tack weld it carefully it from both sides then weld it at a high current using suitably sized wire/rods.

It certainly looks machined, as it has large-radius curved cutting marks all over it. BTW the front plate,which is bent up out of thinner steel, is machined on the face which contacts the block. Can't explain why it cracked, but I do know the bearings were knackered when I bought the engine so maybe fatigue caused by vibration? It is the bit nearest the rear main bearing. I think I'll try clamping and welding it, and then get it faced off again and checked for flatness. I'll heat up the whole plate first which might relieve some stresses. I hate throwing things away!

Seems a lot of hassle to go to. If you're anywhere near Malvern, you could get an entire engine (948 - same backplate?) plus anciliaries for a tenner.

No, the plate is different. This is for the 1098 2" main bearing inline engine, only produced for the MkIII Sprite and MkII Midget. It is thicker than the 948 one which is only pressed. I am using the 1098 gearbox because of better ratios and most importantly synchros. I think the 1098 Minor or A40 one would do as well. I have a shedful of 948 engines! If you use the pressed plate and the 1098 gearbox the clutch cylinder position is wrong. I know, I did that once!

IIRC, there are quite a range of backplates for the A Series - the starter motor moves around according to application, and the thickness also varies.

Did later versions also have a crank seal fitted to it rather than the earlier rope type?

Yes, but only for transverse engines ISTR. A rear crank seal kit is now available for this engine though, from Moss and others. I will still try to weld it and hope for the best.