I have a friend who builds a lot of these engines and 3 of them have dropped valves btween the 3-4 shift at the track to date. Iknow that he doesnt set up his own heads but he does clay the engines. Each engine was broken in on the dyno with no issues. All 3 cars have made several passes at the track after the dyno, but a coupel weeks later they poped. All have done the same thing. this has been over time and not an all of a sudden issue, so I am not trying to blame the guy. Is this an engine build issue or is this the chance you take racing the cars? What else can cause this issue to happen? all 3 heads had aftermarket valves, springs and retainers. There were 3 different drivers who did not missshift.

 

wrong forum, i guess.

 

were these cars all motor or boosted?

 

How high is your friend revving his motor ?

 

junk keepers, bad drivers

 

What exactly happened? Did the keeper end of the valve break? The head of the valve break off? Did the spring break?Did the valve stick in the guide? Did the intake valve hit the exhaust valve?Did the keepers break?was the retainer hitting the underneath of the rocker?Was there enough seal/guide to retainer clearance?Did the spring coil bind?

The list goes on.