When General Motors introduced the LS line of engines, nobody knew at the time, the impact it would have on the aftermarket performance arena. The engine responds exceptionally well to performance mods and can deliver outstanding performance and reliability. However, there are OE shortcomings. These are not something that can’t be overcome, and Racing Power Company (RPC) has the answer.
When GM designed the LS, it was a definite departure from the traditional small block. The design made serious changes to the valvetrain, including the rocker arm design. OE rockers were changed from a familiar stamped-steel design to a cast steel material. This material change offers a substantial reduction of the moving mass in the valvetrain. However, enthusiasts soon learned the trunnion assemblies within the rockers, are not up to the task when power output is increased.
The OE trunnions in early LS engines were made from powdered metal, and the bearings were not a “captured” style. This means there is no cage to keep the bearings in place. Also, the rocker arm’s pivot offers a limited arc and those uncaptured bearings which were under the greatest stress were unable to rotate to distribute the wear like a caged needle bearing assembly. What does this mean? The force exerted on the rocker arms would begin to push the bearing pack out of position. This causes the bearing rollers to fall out of the rocker arm assembly and into the engine’s oiling system – sometimes with catastrophic results.
As LS engines age, the OE rockers’ weak trunnion design has become a problem, as the OE design does not allow the needle bearings to rotate around the pivot of the trunnion. This will cause the needle bearings to wear unevenly.
RPC offers upgraded rocker assemblies made of high-quality steel alloy that feature caged roller bearings and 8620-steel trunnions for superior durability and performance over the stock units. These LS rocker arms are engineered to handle higher spring pressures and high engine RPM. The rockers are a 100-percent drop-in design that meets or exceeds OEM specifications for a hassle-free installation. Each kit includes new mounting bolts.
Contact your local speed shop, online retailer or purchase direct at WWW.USRPC.COM