Re: Flywheel

Posted by Charlie Booher on December 03, 1997 at 09:30:33

In Reply to: Re: Flywheel
posted by scott on December 03, 1997 at 01:05:35

: Thanks for the respose, but I'm still wonering why the opinion that you need to counterbalance the crank if you lighten the flywheel significantly?
:The best answer is : It all depends what you are trying to accomplish. Lightening the flywheel will make the engine more responsive as you are reducing the amount of inertia that the engine has to overcome while accelerating and the engine will slow down quicker when you get out of the throttle. This is desireable if you are building a hot roadster or speedster. It does make the car more difficult to drive smoothly as acceleration and deceleration will be more abrupt when you apply or let off the throttle. The main reason to counterweight the crankshaft is to reduce the amount of whipping at the center main bearing and resultant main bearing wear. The crank will also be less likely to crack and break because it is not flexing as much (in theory). Marco is correct in that, if you add counterweights, reduce the flywheel a like amount. That's what the factory did in the later B motors. If you are building a race motor where engine life is secondary, then use an uncounterweighted crank and the lightest flywheel (aluminum) that you can find. Mike's thoughts, however, are wise. If you are using the car as it was origionally intended, leave it alone. They have lasted almost 70 years just as they are. ( But I sure like a good race motor)

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