Rocker Arms

Is your valvetrain making noise, or does a project with a new camshaft need rocker arms that match the lift and RPM? In this category you will find rocker arms, rocker arm kits, pivots and shim kits for Honda B- and H-series, Chevy SBC and LS3 as well as Jeep CJ and Wrangler, among others.

What rocker arms do in the valvetrain

The rocker arms transfer the motion from the camshaft to the valves, depending on the engine either directly or via lifters and pushrods. The ratio, i.e. the relationship between the two sides of the arm, affects how much the valve is lifted relative to the cam profile. That is why rocker arms should be chosen together with the camshaft, valve springs and pushrods.

How to choose rocker arms

• Engine: The parts are engine-specific, e.g. Skunk2 kits for Honda B- and H-series, COMP Cams for Chevy SBC and LS3, and Omix parts for Jeep CJ and Wrangler.
• Design: Choose between OE-style replacement kits and, for example, a shaft-mounted rocker arm kit such as the COMP Cams Max-Lift BSR Shaft Rocker Kit.
• Ratio and lift: More lift may require checking spring capacity, valve-to-piston clearance and pushrod length.

Ferrea and S&S Cycle are also among the brands in this category.

Installation and geometry

Where the rocker arm contacts the tip of the valve stem typically depends on pushrod length, cylinder head and any machining. For some engines, shim kits for the rocker arm pedestals are available, e.g. from Ford Racing, which can be used to adjust the height. Check the valve lash after installation, and inspect rocker arms and valve tips for wear while the cylinder head is apart anyway.

Frequently asked questions

Do I need to replace all rocker arms at once?

That depends on wear and purpose. With a changed ratio or a new camshaft, the whole set is typically replaced so all valves work the same. For a single damaged arm, one replacement part may be enough if the rest are in good condition.

What does the ratio of a rocker arm mean?

The ratio indicates how much the cam lift is multiplied before it reaches the valve. A higher ratio gives more valve lift but may require different springs, checking piston clearance and an adjusted pushrod length.

How do I check the geometry after installation?

A common method is to mark the top of the valve stem and turn the engine over. The contact pattern should typically be narrow and centered. If it sits out towards the edge, the pushrod length or pedestal height may need to be adjusted.