The camshaft lift bolt is a wear item in the 2ZZ engine which is often forgotten with catastrophic results..
Each camshaft has one of these lift bolts. They are part of the changeover mechanism and they wear over time.
As they’re not quite visible (you can only see the heads when you lift the cam cover) you wouldn’t normally recognize the wear in these parts, but when you unscrew them, you might be in for a surprise!
When ignored, the tips of the bolt could sheer off and drop into the cam mechanism with catastrophic results.
We recommend to replace these bolts every 40k miles or 60k km on road cars and every season on a race car.
You need two of these bolts per engine and they’re located under the cam cover at the timing chain side in between the two camshafts.