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World Class ASE tech
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It depends on if the crank weights are heavy or too light. The cranks are balanced in a machine with a strobe light much like a wheel balancer that balances on the car. If the counter weights on the crank are light they drill and add heavy metal. If it is heavy then they just drill a hole. The blinking light tells the operator were to add or remove the weight.
 

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First the weight of the recipricating components must be detemined. The balancing shop will weigh all the pistons and rods, then lighten the heavier ones to match the weight of the lightest ones. Then they add in for the weight of the wrist pin, rings and bearings. After all that a temporary counter weight is added to the crank opposite each bob-weight. Then it is spun in the machine to determine where weight needs to be removed (or added) to make the crankshaft balance out neutrally.

If your engine uses counter a weighted flywheel and vibration damper, then they must be installed on the crank during the balancing process.

If the bob-weights are too heavy the balancing would be accomplished by drilling or machining to remove the appropriate amount of weight. If the bob-weights are too light, then "heavy metal" is added to compensate.

Usually if you are switching to a higher quality piston, it will be lighter than stock requiring bob-weights to be reduced in weight.
 

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King of my Man-cave.
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john56h said:
First the weight of the recipricating components must be detemined. The balancing shop will weigh all the pistons and rods, then lighten the heavier ones to match the weight of the lightest ones. Then they add in for the weight of the wrist pin, rings and bearings. After all that a temporary counter weight is added to the crank opposite each bob-weight. Then it is spun in the machine to determine where weight needs to be removed (or added) to make the crankshaft balance out neutrally.

If your engine uses counter a weighted flywheel and vibration damper, then they must be installed on the crank during the balancing process.

If the bob-weights are too heavy the balancing would be accomplished by drilling or machining to remove the appropriate amount of weight. If the bob-weights are too light, then "heavy metal" is added to compensate.

Usually if you are switching to a higher quality piston, it will be lighter than stock requiring bob-weights to be reduced in weight.
Well said except that it's the bob-weight that is temporary and the counterweight that is part of the crankshaft.

to,m
 

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Philippines Cowboy
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There is a more basic question: Why are you seeking balancing? If you're making a radical change in component weight, there might be a need, but, in most cases, the stock balance is sufficient.

Understand that, if you take a given engine and have it custom balanced, there will be NO change in power at a given engine speed and NO measurable change in vehicle performance.
 

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Discussion Starter · #6 ·
not for ponnies

BillyShope said:
Understand that, if you take a given engine and have it custom balanced, there will be NO change in power at a given engine speed and NO measurable change in vehicle performance.
You mean I won't get 100 more hp, what the hell? J/K. Yeah I know there is no horse power gain at all and even if there is, it's so insignificant it's not worth it. I'm not doing it for ponnies. I know plenty of guys before and after balancing and they and myself love it. The engine has the same power yet runs that much more smoother and a balance job is cheap and extends life of the parts. I have a flathead Studebaker straight 6 and the smoother the better. Why not have an engine with the same horsepower plus a couple hundred bux to have it run like glass.
 
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