Quote:
Originally Posted by PAUL K
The press fit of the balancer helps transfer harmonics to the damper and the transfer of the dampened harmonics back through the crank. According to damper experts they say increasing the torque of the balancer bolt will not increase the performance of the damper at all.
|
This has been the information I have gleaned from reading about torsional vibration, crankshaft balancing, and talking to the folks at ATI, BHJ and others. The ATI balancers are a "light press fit", about .0005"-.0075" press. We always "overtightened" the large bolt to 200 Ft. Lbs. with a balancer and 235 ft. Lbs. with just a hub on the blower engines. Used a very thick hardened washer, a L9 bolt, locktite on the threads and ARP lube under the bolt head between the washer. I know this sounds like overkill and may not add any additional benefit. But I have seen what happens when a balancer bolt backs off or the fit is just a slip fit in a race application. Engine doesn't have to be high performance to break a crank nose. When I worked at the Pontiac dealer we had a campaign for balancer failure on the "T Grand". (Pontiac Chevette" The bolt would come loose, sometimes break in the crankshaft, sometimes break the nose off, sometimes just beat up the keyway. Those engines probably made 70-80 HP. Had to repair a bunch of therm. Replaced a few crankshafts.