TORQUE PLATE HONING GM LS-SERIES ENGINES
We have found that due to the length of the head bolts and the fact that they finish approximately 1-1/2 inches from the mains, considerable bore distortion will occur if torque plates are not used when finish honing the GM LS series engines. We use two torque plates and all 15 bolts per side fully torqued. We routinely find 0.0025” cylinder distortion if we don’t use both plates and all the bolts in a finished form. When you consider that an LS-3 has a piston-to-wall clearance spec of 0.0008” you can see why a straight and accurate bore finish is critical. We also line-hone the blocks with two torque plates and bolts installed since we have measured 0.0005” distortion in the hosing bore. This might be alright for a street car, but in a race motor it is something to consider.
Sylvain Tremblay
Les Ateliers de Moteur Competi-tech Inc.
Quebec, Canada
February, 2014
