What do Eccentric Idler Pulleys do? And when do you need them?

When you are doing a timing service on your WRX, STI, or other Subaru with an EJ205,207,255,0r 257 engine, it is not that unusual for the timing marks to be slightly off.

 

But if your heads or block have been resurfaced, or if you are using thicker head-gaskets, you may find that your timing marks are something like half a timing belt tooth off.  If that is the case, and you want to make sure that your engine is in proper time, you should be able to get them lined up by using a set of eccentric timing belt idler pulleys.

 

We like the Roger Clark Eccentric Idlers because they use a dual bering just like the factory bearings, so they will be just as durable as the stock pulleys.

 

We go through installing them in this video, and you can see how much of a difference these made on the engine.

 

Thanks for watching and Stay Tuned!