Precision Balance Vs. Street Balanced engines.
Perpetual Balance offers complete precision balancing of your rotating assemblies, that is, we balance your crankshaft as a complete assembly with the Harmonic damper and flexplate/flywheel installed on the crankshaft during the balancing operation, this is the most accurate method of balancing your engine. Whether we supply your Harmonic balancer and flexplate or use your existing good condition damper and flexplate to achieve precision balancing. Precision Balancing should also include correcting the weights of the pistons and both the rotating and reciprocating ends of the rods to within a 1/2 gram. Using the corrected weights, then the bobweight is determined specifically for your rotating assembly
Street or Average balancing does not include correcting the weights of the piston and rods. Only the crankshaft is balanced. Internally balanced engines are frequently balanced without the damper or flexplate installed on the crankshaft during the balancing operation. Externally balanced engines may use a damper and flexplate from the engine family, not necessarily the damper and flexplate/flywheel that is going to be used on the engine. All parts including harmonic dampers and flexplates/flywheels have tolerances. The only way to precision balance your engine is to use the parts that will be assembled with the engine while balancing.
Don't let a few grams of weight shorten your engines life. The chart below list the amount of force applied to the Main bearings of an engine with new pistons that are 7, 14, and 28 grams heavier or lighter than the original pistons.
IT A FACT!
unbalance @ 4" 2,000 rpm 4,000 rpm 6,000 rpm 8,000 rpm
7 grams 7lbs 28 lbs 63 lbs 112 lbs
14 grams 14 lbs 56 lbs 126 lbs 224 lbs
28 grams 28 lbs 112 lbs 252 lbs 448 lbs