Why Valve Train Upgrades Matter in High-Performance LS Engines

The valve train is responsible for transferring camshaft movement to the valves, often thousands of times per minute. In a standard engine it must be reliable; in a high-performance LS engine it must also cope with increased lift, higher rpm, stronger spring pressures and greater thermal load.

The valve train works under demanding conditions
A typical system includes the camshaft, lifters, pushrods, rocker arms, valves, springs, retainers and locks. Every component must move in the correct relationship. At high rpm, even a small loss of control can cause valve float, inconsistent cylinder filling or component damage.

Valve float occurs when the spring can no longer keep the valve train following the camshaft profile. The engine may stop making power, misfire or suffer mechanical damage. High lift and aggressive ramp rates increase the demands placed on the system.

Common causes of valve-train trouble
Incorrect spring selection is a frequent problem. Springs must provide suitable seat pressure, open pressure and travel for the chosen camshaft and rpm range. Too little pressure can allow control problems, while excessive pressure can accelerate wear.

Pushrod length is also important. Changes to heads, deck height, rocker geometry or lifter configuration can alter the correct length. Incorrect geometry may increase wear and affect valve motion.

Other risks include worn lifters, damaged rocker bearings, inadequate lubrication, incorrect preload and insufficient clearance. A component that looks acceptable during a quick inspection may not be suitable for a demanding build.

Choosing components as a system
A valve-train package should be specified around the camshaft and engine’s intended operating range. Springs, retainers, locks, pushrods and lifters need to be compatible. The correct choice also depends on whether the engine is naturally aspirated, supercharged or turbocharged.

High-quality components are valuable, but quality alone does not compensate for incorrect specification or installation. A premium part installed with the wrong clearance can still fail.

Inspection and setup
During assembly, measure rather than assume. Check installed spring height, coil bind, retainer clearance, rocker geometry, pushrod length and lifter preload. Confirm that the timing set is correctly installed and that the engine is lubricated and primed appropriately.

A valve-train upgrade can deliver stronger performance and improved reliability, but only when the parts and setup are matched. BYE Performance can help identify the requirements of your LS combination before you commit to a parts list.

Phone: (08) 9451 9696