Engine Balancing (LS3)

During the powertrain build process, balance weights may be added to the crankshaft balancer and/or manual transmission flywheel, as required.

In order to maintain engine/clutch assembly balance, it may be necessary to install or remove balance weights as detailed below:

Crankshaft Balancer

• Existing RPO-LS3/LS7 balancer onto existing engine: The balancer position must be marked prior to removal and installed to the original position. Refer to Crankshaft Balancer Removal .
• Existing RPO-LS9 balancer onto existing engine: It is not necessary to mark the balancer prior to removal. The balancer is positioned by a key located in the front of crankshaft.
• New balancer onto an existing engine: Install the same size balance weights into the new balancer in the same location as the old balancer. Refer to Crankshaft Balancer Cleaning and Inspection .

Engine Flywheel

• The RPO-LS3/LS7 flywheel, clutch disc, and pressure plate are each individually balanced components and are available separately. The pressure plate mounts, or locates, onto the flywheel dowel pins in the flywheel. If the pressure plate is not aligned properly onto the dowel pins and tightened down, the pins may bend and the plate may be incorrectly positioned, which will affect component balance.
• The RPO-LS9 clutch discs and pressure plate are a balanced assembly and not available separately. The pressure plate mounts, or locates, onto the six flywheel dowel pins. If the pressure plate is not aligned properly onto the dowel pins and tightened down, the pins may bend and the plate may be incorrectly positioned, which will affect component balance.
• Existing flywheel, clutch, and pressure plate onto the existing engine: Pressure plate position to flywheel must be marked prior to removal and installed to the original position. Flywheel position to crankshaft must be marked prior to removal and installed to the original position.
• Existing flywheel, clutch, and pressure plate onto a new engine: Pressure plate position to flywheel must be marked prior to removal and installed to the original position. Flywheel position to crankshaft must be marked prior to removal and installed to the similar position on the new engine. Do not remove balance weights from flywheel, if applicable.
• New flywheel onto an existing engine: Install the same size balance weights into the new flywheel in the same location as the old flywheel. Install the new flywheel to a similar position on the new engine.
• New flywheel, clutch, and pressure plate onto a new engine: Do not install balance weights.