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Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Fan Belt Doesn't Fit

I got the tranny and engine back in my '59. Decided to install a new fan belt and keep the old one as a spare. I ordered a belt and it is the 10 X 900 size but it is too short. Were there different size generator/crankshaft/fan pulleys for the MGA?
Steven B

I believe all the A's were the same but they are different from the B's. You may have mixed components as part swaps between A's & B's are not uncommon. Take you old belt to a parts hose and have it measured.
John H

Yes. The Twin Cam used a larger generator pulley to slow it down some in light of higher expected engine speed. I like the larger pulley, as my car doesn't spend much time idling.

It is also common these days that a replacement generator for the MGA would actually be a late model MGA or MGB generator (push connectors rather than screw posts). If/when a replacement generator includes a pulley, it will most likely be the larger diameter pulley (MGB style). In this case a 930mm belt works better (36-5/8"), so you don't have to dismount the generator to get the belt over the pulley.
Barney Gaylord

I recently ordered a fan belt from Moss to keep as a spare and it was a bit too small. As far as I can tell, I have all original pulleys on my MkII. I see if I can locate the 930 mm size Barney mentioned.
Ken Doris

I have just picked up a 2nd hand dynamo from Tatton show - just in time as mine packed up on the way home - ignition light on for 30 miles but made it - took it apart today - commutator knackered as was the rear bearing. The pulley on the one I bought has a smaller pulley than mine and I was told it was from a 1500 - so there will be 2 different fan belts - now to swap over the pulleys. - cheers Cam
Cam Cunningham

Caution: "commutator knackered as was the rear bearing" is a common sign of meltdown from overcharging caused by a failed control box.

When you install the replacement generator, test the generator by itself to be sure it works. Then also be sure to test and adjust the control box before you try to drive it, as a faulty control box could kill the replacement generater in short order. You may need to replace the control box if adjustment cannot stop overcharging.
Barney Gaylord

Thanks for the warning Barney - Control box was fitted new by previous owner - what do I have to adjust if it is overcharging? - cheers Cam
Cam Cunningham

Hi Again Barney - just looked at your website and got the info from there - many thanks - cheers Cam
Cam Cunningham

This thread was discussed between 30/05/2007 and 05/06/2007

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