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MG MGB Technical - Replacement alternator

Yesterday on a friend of a friend's CB car. A 'universal' 16/17/18ACR of 55 amps output and a new belt of the same number that came off - 10900. The only way the belt would go on was by fitting it before the mounting bolts! With the body sitting on the engine mount there is still at least 1/2" of movement in the adjuster that can't be used, and with everything installed the adjuster has barely moved from the minimum position.

Two other people on the MGOC forum found the same thing, so I suspect the body on these is fatter. One was offered alternative belts of 10925 and 10950 but not unsurprisingly at the time stayed with the original. Maybe the 10925 would be a better bet, I was aware of the 10950 for late RBs but felt that might be too big.
paulh4

I don't know what MGOC are offering now but I got a universal one for my midget years back and IIRC it came with the pully already fitted so could that be a different size to the previous one too?

As part of service I later bought a generic fan belt from MGOC and although it seemed about the same length as fitted one when using nails on a board to stretch measure it wasn't certain. It also had an awful high stink from it as if rubber colour (it was very black) and (too much) rubber odour had been painted on.

I couldn't get a good fit with this belt so I ordered a proper Gates from elsewhere plus another Gates of the alternative size. The correct size Gates fitted and I gave away the odorous belt and sold on at loss the other Gates belt.



Nigel Atkins

It was - but fractionally smaller.
paulh4

I've found fractional differences at pulley and in belts can translate to a surprising difference to the adjustment slide.

I'd strongly recommend to your friend of a friend and the two others that they give away any modern generic belts from the usual suppliers and buy the likes of Gates.

Obviously I've no idea if the standard belt will still fit to these new alternators but in my experience the likes of a Gates belt stands more chance than the cheaper made belts being offered by the usual suppliers.

As I put the small difference in size was difficult to see and prove as it was small but the Gates belt I bought was a better fit and looked a great deal more confidence inspiring manufacture quality.

AXX10 X 0900 LA (10mm x 900mm, outer length 910mm)

Gates 6216MC V-belt - https://gatesautocat.com/p/v-belt/gates/6216mc.html

925mm may give a lot of difference so an intermediate size of 913mm -
Gates 6272MC - https://gatesautocat.com/p/v-belt/gates/6272mc.html

925mm = Gates 6217MC - https://gatesautocat.com/p/v-belt/gates/6217mc.html
Nigel Atkins

This thread was discussed between 22/04/2021 and 23/04/2021

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.