1968 Volkswagen Squareback Valve Train Components

What Are Valve Train Components?

The valve train is one of the most critical systems in any internal combustion engine. It governs the precise opening and closing of intake and exhaust valves, synchronizing their movement with the rotation of the crankshaft to control airflow in and out of each cylinder. A properly functioning valve train is essential for combustion efficiency, power output, fuel economy, and long engine life. When any part of this system wears out or falls out of sync, the consequences range from rough idling and poor performance to catastrophic engine damage.

Valve train components span a broad range of parts — from the timing chains and belts that keep everything synchronized, to the camshafts that dictate valve lift and duration, to the rocker arms, lifters, and pushrods that translate cam motion into valve movement. Whether you're performing routine maintenance, rebuilding a worn-out engine, or chasing more performance, understanding this system is key to making the right parts choices.

Key Subcategories

The valve train category covers several distinct component groups, each with a specific role in engine operation:

• Engine Timing Chain Kits – Complete kit solutions for replacing the timing chain, guides, tensioners, and sprockets. Timing chain kits are one of the most important maintenance items on chain-driven engines, as a stretched or broken chain can cause severe valve and piston damage.
• Engine Camshafts – The camshaft is the heart of the valve train, directly controlling valve timing, lift, and duration. Upgrading a camshaft is one of the most impactful modifications for improving engine performance and power delivery.
• Engine Rocker Arms – Rocker arms transfer motion from the camshaft or pushrods to the valves. High-performance or roller-style rocker arms can reduce friction and improve valve actuation at higher RPM.
• Engine Timing Belt Kits – For engines that use a rubber timing belt rather than a chain, complete kit replacements ensure all wear components — belts, tensioners, and idlers — are renewed together for reliable operation.
• Engine Valve Lifters – Lifters (also called tappets) ride on the camshaft lobes and initiate valve actuation. Hydraulic lifters self-adjust for quiet operation, while solid lifters are preferred in high-performance and racing applications.

Top Brands in Valve Train Components

Choosing quality components from trusted manufacturers is especially important in the valve train, where precision tolerances and material quality directly affect engine longevity and performance.

Cloyes is the dominant force in engine timing chain solutions, offering comprehensive kits engineered to meet or exceed OEM specifications across a vast range of domestic and import applications. Cloyes kits are widely trusted by professional rebuilders and DIY enthusiasts alike for their complete coverage and quality components.

S&S Cycle is a legendary American manufacturer with roots going back to 1958, specializing in high-performance valve train and engine components for Harley-Davidson motorcycles. Founded by George J. Smith and Stanley Stankos, S&S is the go-to brand for serious Harley-Davidson builders and racers seeking maximum power, reliability, and American-made quality.

Gates brings decades of OEM-level expertise to timing belt kits and related drive components. Gates is the world's largest manufacturer of PowerGrip™ Timing Belts and PowerGrip Kits, and serves as the Original Equipment Manufacturer for over 35 vehicle manufacturers worldwide — with kits that are OE-equivalent or better in service life, quality, and performance.

Speedmaster offers a broad catalog of performance-oriented valve train parts, including cylinder heads, timing sets, and related components geared toward builders looking to maximize engine output on a budget without sacrificing reliability.

Melling is a well-established name in OEM-style engine components, with an extensive catalog of valve train parts including camshafts, lifters, and timing sets. Melling is a go-to choice for engine rebuilders who need reliable, factory-spec replacement parts across a wide range of vehicle applications.

Choosing the Right Valve Train Parts

When shopping for valve train components, always verify compatibility with your specific engine — even small variations in displacement, year, or trim level can mean different timing specifications or component geometry. For performance upgrades like camshafts or rocker arms, consider how the changes interact with the rest of the engine, including springs, pistons, and fuel delivery. And for maintenance items like timing chains or belts, it's best practice to replace the entire system — tensioners, guides, and sprockets — at once, rather than swapping individual pieces, to ensure uniform wear and avoid premature failure.