What is a Rocker Retainer?Updated 18 minutes ago

A Rocker Retainer is a clip that holds a rocker arm onto its pivot, lash adjuster or lifter. It's designed to keep the rocker in place if valve spring pressure is lost for a split second.

Why some engines need them

Many modern engines use rocker arms (also called finger followers) that aren't fixed in place. One end sits on a pivot or lash adjuster, the other end sits on the valve, and the camshaft pushes down in the middle. Only valve spring pressure holds the rocker there.

If that pressure drops for a moment, from valve float, valve bounce, a sticking valve or an over-rev, the rocker can lift and walk off its pivot. A loose rocker can cause a misfire, or get caught by the camshaft and seriously damage the engine.

Some prestige engines, like the BMW B58 in the GR Supra and the Lexus 2UR-GSE V8, use rocker retention from the factory for this reason.

How a Rocker Retainer works

The clip locates in a groove on the part the rocker sits on. In our FA/FB, G16E-GTS and SR20 kits, that's a Denstoj pivot, lash adjuster or solid lifter with our retaining groove. On the 4G63, the factory lash adjusters already have a groove, so the kit is clips only.

In normal running, the clip doesn't affect how the rocker works. If the rocker tries to lift off, the clip is designed to catch it and hold it in place until valve spring pressure returns. This reduces the risk of a dropped rocker and a costly rebuild.

What a Rocker Retainer doesn't do

It's a safety net, not a performance part. It doesn't make the valvetrain stronger or raise your safe rev limit, and a severe over-rev can still break the clips. See Do Rocker Retainers let me rev my engine higher?

Which engines do you make them for?

• Subaru FA and FB (Toyota 86, GR86, Subaru BRZ, WRX and more)
• Toyota G16E-GTS (GR Yaris and GR Corolla)
• Nissan SR20DE and SR20DET (hydraulic head)
• Mitsubishi 4G63 (Lancer Evolution)

See Which engines do you make parts for? for every kit.