Why Rocker Retainers?

The short version

Our Rocker Retainer reduces the risk. It's not a fix for an inadequate setup

Many performance engines use "floating" rocker arms: nothing holds the rocker in place except valve spring pressure. For the split second a valve floats, bounces or sticks, that pressure disappears and the rocker can walk out of position. Our Rocker Retainer is designed to hold it there until the spring takes control again.

Expensive engines like the BMW B58 and Lexus 2UR-GSE come with retainers from the factory. We make them for the engines that don't.

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Rather watch? The full story in 11 minutes

Filmed on the Subaru FA20 in the Toyota 86, but the problem is the same on every floating-rocker engine. Prefer to read? Read the written version with diagrams.

The problem with a floating rocker

In a rocker-arm valvetrain, one end of the rocker sits on a pivot, the other on the valve, and the cam presses on a roller between them, closer to the valve end. While the valve spring is in control, it clamps all three together. That's most of the time, and most of the time it's fine.

1. Normal running Cam Roller Rocker Pivot Valve spring Spring load clamps the rocker between the cam, pivot and valve. 2. Valve floats or sticks Gap Stuck open The valve floats, bounces or sticks. The rocker loses its clamp. 3. The rocker lets go rocker cover Off the pivot Nothing holds it down, so it lifts off the pivot. The cam can fling it.
The rocker is only clamped while the valve spring is in control.

If you're lucky, a loose rocker settles in the head and you get a misfire while the cylinder runs on its other valve. If you're not, the cam picks it up: holes punched in the rocker cover, oil on the exhaust, dropped valves and destroyed engines.

The real cause: losing valve spring pressure

With the right geometry, weight and RPM you can calculate the ideal spring pressure, and the manufacturers do. But real engines hit edge cases no calculation covers:

  • Valve float: not enough spring pressure for the RPM, often from a missed downshift or limiter abuse.
  • Valve bounce: harmonics that bounce the valve off its seat.
  • Valve stick: carbon build-up holding the valve open for a moment.

Our Rocker Retainer reduces the risk in that split second. It isn't a fix for an inadequate setup: if an engine is losing spring pressure constantly, a clip only masks the real problem.

How our Rocker Retainers work

1. Factory pivot Nothing holds the rocker down Lifts off Rounded top,no groove Only spring pressure keeps the rocker seated. Lose it and the rocker lifts off. 2. Our pivot New part with a groove Slight mushroomhead Machined groovefor the clip It replaces the factory pivot. A clip alone has nothing to hook into without the groove. 3. Our Rocker Retainer Pivot + clip: rocker is retained Clip Clip sits inthe groove The clip never touches in normal running. If the rocker lifts, the clip catches it.
Two parts, not just a clip: our pivot replaces the factory one, and the clip hooks into its groove.

We replace the factory pivot, or hydraulic lash adjuster, with one of ours that has a groove, and add a hardened clip that hooks into it. Everything else stays factory. The approach is the same as the BMW B58 and Lexus 2UR-GSE, just engineered for engines that were built to a price.

Find your engine

Subaru FA / FB

Toyota 86, GR86, Subaru BRZ, WRX

Boxer layout, so gravity works against the rocker. Every FA20, FA24 and FB engine uses floating rockers, and the spring recall didn't change that.

Shop the kitFull explainer

Toyota G16E-GTS

GR Yaris, GR Corolla

Known for dropping rockers when pushed. Choose drop-in hydraulic lash adjusters with our Rocker Retainers, or a solid pivot conversion for higher RPM.

Hydraulic kitSolid pivot kitWhich one?

Nissan SR20

SR20DE, SR20DET (S13, S14, S15, N15)

Famous for dropping rockers under high RPM, limiter cuts and over-revs. One rocker drives two valves, so a loose one does double the damage.

Hydraulic kitSolid pivot kit

Mitsubishi 4G63

Lancer Evolution I to IX, DSM

Proven in time attack and drag engines making over 1,300 hp at 10,000 RPM.

Evo IV to IX (pressed)Evo I to III (cast)

In development: Toyota 2GR, Toyota/Lexus 3UR-FE, Audi EA855 (RS3) and a 4G63 solid pivot kit. Email support@denstoj.com.au to join the waiting list. Every kit has an install video.

Examples of dropped rockers

"I found out the hard way. I started my Toyota 86, heard some sound, didn't think much of it, and then on my 12 minute drive to my appointment I noticed smoke and a trail of oil. I'd just had it rebuilt with upgraded non-beehive springs, and it still fell off. Literally 5.8k kilometres. For less than $1,000 I'd rather have peace of mind. This is a no-brainer investment."

Ricardo, Toyota 86, before he ordered our FA20 kit
Hand holding the dislodged FA20 rocker arm next to the piece of rocker cover it punched out Broken piece of rocker cover held up beside the FA20 engine it was punched out of

"First session of open lapping my engine blew. One of the rockers blasted a hole in my valve cover."

Patrick, Toyota 86 time attack, High Plains Raceway, Colorado
Patrick's Instagram post from High Plains Raceway: his Toyota 86 time attack car and his note that a rocker blasted a hole in the valve cover The ejected FA20 rocker arm beside the piece of valve cover it punched out Looking through the hole in Patrick's valve cover at the exposed camshaft Engine oil sprayed across the undertray, with the rocker and broken cover lying in it

Push the limit. Not past it.

How it should be from the factory

Your car should come home on its own wheels, not on a tilt tray. Find the kit for your engine and get back to enjoying the drive.

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