we have a box of broken rollers, they really take a beating. Why a part fails has always been tough to solve unless the obvious, lash set to tight or loose, poor quality part, lack of lubrication.
I try and inspect the valve train on our roller engine as often as possible and it's still easy to miss a part that's going to fail.
I try to put these engines in perspective, I've read the engine fires a spark 50 times every second @ 7000 rpm's
![](/ubbthreads/images/graemlins/crazy.gif)
that means every part in the valve train is reaching it's minimum and maximum limits thousands of times during a pass at the drag strip.
![](/ubbthreads/images/graemlins/crazy.gif)