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MG MGA - flywheel crankshaft

hi all
I am currently building up an 1800 three main for my '59 MGA. The flywheel is off my 1600. It will fit on the 1800 crankshaft in any position and I am a bit concerned about the balance. Does anyone know how critical this is or how to fit it? I am told that if it fits in any position then it doesn't matter. There is a faint mark on the circumference of the flywheel, not sure if this means anything. I thought that it had to be in the right position in relation to the crankshaft.

Cheers, Matthew
M S Randell

The only way it would make a difference is if the whole assembly were balanced by a machine shop. Pistons, Rods, Crank, Flywheel and clutch cover. Normally the flywheel and crank are balanced separately and the location between is not considered.
R J Brown

RJ, I thought there was a relationship between the flywheel and crank. There is a 1/4 stamped on the rim of the flywheel, which I think is supposed to line up with the cylinder 1 and 4 crankshaft throws. In Matthews case it wouldn't matter since he is using a different flywheel/crank combination anyway.
G Goeppner

I was unaware of the 1/4 mark on the flywheel. I learn things here all the time. here is a picture of a flywheel and a crank situated as George states.

R J Brown

Don't wory about it.

The flywheel is not counterbalanced as some 'V' engines are and will be balanced on its own - or at least as balanced as they ever are from the factory.

I used to have all my engines balanced whether for race or street, but this can be an expensive proposition for the street and many people don't bother.

On the 3 main, the darned flywheel goes swiftly out of balance if the starter grinds bits off the ring gear. Not a big deal on the street, but rather a pain if you just paid a lot of money for the street. I adapt a pre-engaged starter off another BLMC product so as not to have that problem.
Bill Spohn

Thanks everyone. I knew I'd get an answer here. So the general concensus is that it doesn't matter? But, I might line up the marks with the 1 and 4 crank throws anyway.
Thanks for the help.
M S Randell

This thread was discussed on 08/07/2008

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