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MG MGA - Flywheel Weight

I have just got my 5-bearing 1800 engine out of the car and on the bench. First job was to weigh the flywheel - 20lbs.

I have had a quick look through the MGA and MGB archives on lightening the flywheel. A couple of points I noted:

1. Barney said that the standard flywheel got a bit thin if reduced below 20lbs. Are the A and B flywheels essentially the same or is Barney's advice relevant only to the A version?

2. Some of the guys over on the B forum said that lowering the weight below 20lb is of little benefit for road cars.

Any comments on whether I should lighten below 20lbs most welcome. Also a target weight please - 16lbs?

Steve Gyles

Below 20 pounds is not much help on the street. If you get a kick out of burning a little rubber with a small engine you need some mass in the flywheel. That's where you get a good launch off the line. If you don't want to kill it at every traffic light, don't go too light in the flywheel. A 14 pound alloy flywheel is only money if you want one, but you might not like the way it drives on the street. If you lighten the standard flywheel below 20 pounds, take as much weight as possible out of the rim, and don't bother thinning the center out. The largest part of the inertia is in the fast moving part farthest from the center.
Barney Gaylord

I took the flywheel to my local machine shop and they said they could not take anything worth while out of it without weakening it; confirming much of what Barney said.

I will stay with it as is.

Steve Gyles

This thread was discussed between 14/11/2009 and 16/11/2009

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