Why does the G16E-GTS need Rocker Retainers?Updated 18 minutes ago

The Toyota G16E-GTS in the GR Yaris and GR Corolla uses floating roller rockers. Like the FA20 in the Toyota 86, each rocker is held in place only by valve spring pressure.

When the G16E-GTS first came out, we inspected the valvetrain and recognised the same weak point we'd already addressed on the FA20. We've seen that rocker design fail, so we developed a retainer specifically for the G16E-GTS.

How it works

Our lash adjusters (or solid lifters) have a retaining groove. A heat-treated high-carbon steel clip attaches to the rocker and sits in that groove. In normal running, the clip doesn't affect the operation of the rocker. However, if a valve floats, bounces or sticks and the rocker loses spring pressure for a split second, the clip is designed to catch the rocker and hold it in place until valve spring pressure is regained. This massively reduces the risk of it walking off.

Is this a fix for valve float?

No. It's a safety net. You still need valve springs, a cam and a tune that suit your build. The retainer adds a layer of reliability for the moments when things get lively: a missed shift, a hard limiter hit, or a misfire. A severe over-rev can still break the clips.

It's not a new idea either. Higher-end engines with this style of rocker, such as the BMW B58 in the GR Supra and the Lexus 2UR-GSE V8 in the Lexus LC500, use rocker retention from the factory.

Choosing a kit? See G16E-GTS: hydraulic lash adjusters or solid lifters?