CROWN AS-PISTON 1504621 - Caterpillar

Caterpillar Products: All
3500B and 3500C Engines Engine: Commercial With Mechanical Unit Injector
3500An imbalance in the valve bridge's load can be caused by mismatched springs. The outboard valve stem acts as a pilot in the bridge's round hole in order to keep the bridge square with the system. If lower load springs are used on either valve, an imbalance on the bridge will result. The bridge will exert a load that bends the stem. The bridge will exert a load that may cause a failure on the stem at the keeper groove.Use the same springs on both valves under a common bridge.The retainer locks for the valves have recently changed in appearance. The retainer locks formerly had a flat, top edge. The new retainer locks have a top edge that is rounded. Although the retainer locks have a different appearances, the critical dimensions are the same. The old retainer locks and the new retainer locks can be used interchangeably. The retainer locks must be used in like pairs.The rotocoil assemblies must be used with the correct spring sets to ensure valve rotation.The 197-6999 Rotocoil Assembly must be used with the following springs.
101-1177 Spring
101-1180 Spring The 197-7062 Rotocoil Assembly must be used with the following springs.
194-4902 Spring
281-6157 Spring The 197-7063 Rotocoil Assembly must be used with the following springs.
194-4902 Spring
281-6157 Spring