[Camarowguy]

Originally Posted by trm0002

I don't disagree at all with what you're saying my friend. That said, I just made an opinion based on Mike's cam replacement- not overly aggressive from what he said- that valve clearance wouldn't have been an issue unless the timing was off. If the timing was off, wouldn't he have immediately noticed issues?

If cam timing was off, I doubt it would run correctly...or even run at all. I'm not so sure how "off" you can get the timing and the engine still run....but most engines I've encountered wouldn't run with a tooth off. My theory is this: the ls3 has no valve reliefs, so that right there would scare me to put a cam in without checking the valve to piston clearance. Also, it's a standard transmission car...you can over rev them easier and also accidentally mechanically over rev it...in which the rev limiter would do nothing to protect the engine in that case. The op never mentioned that he had ever done this so who knows. Also, the rev limiter had be raised. Another strike against the situation. I feel like there are many factors that come into play with this and make the ptvc issue a probable cause. Think about this one small tidbit. What if the valve springs weren't shunned to the correct installed height. Say the shop just put them on. Then it's missing say 20lbs of seat pressure and maybe 30-50lbs open pressure. Everyone knows the valves are huge and heavy, so that makes the spring setup that much more important.

He could possibly had acceptable ptvc, but factor in numerous redound shifts with incorrectly set up springs or possibly weak springs and that will explain why the valves were smacking the pistons. I also feel confident that if the pin broke and the valves contacted (which they would) it wouldnt be so pronounced as in his pics. To me it looks like it's been happening for Sind time now....not just a split second during the failure. I have no doubt the cause of failure is caused by the valvetrain.