cobalt

I had a catastrophic failure of a valve on my 993 turbocharged engine. Intake valve for no reason let go. We have been trying to diagnose the cause and although over rev is the likely cause all data shows we never exceeded 6400 rpms. The only other solution we can think of is a failed hydraulic lifter.

I was considering modifying the stock 993 hydraulic lifters to mechanical. It will take some machining and sleeving to get it to work. Very much like the EVO racing designs.

I was curious if someone can measure the Inside dia of the rocker for me or the older style pin it rides on. I am not sure if the shaft dia are interchangeable if I chose to go another route.

Thx.

JasonAndreas

Were you sweeping or steady state on the dyno?

cobalt

We had just completed a sweeping run. When it came down to idle just about 1200 rpms it sent out blue smoke and then a big ball of flame and came to a stop. Gave no signs of a problem or made any obvious noise but I was wearing head gear since it is about 110+ db at WOT.

cobalt

Anyone?