Picture this. '97 Camaro Lt1 (with 39,000 miles) and I doing some Open Track/Club Racing at Thunderhill. We are having a great time. Car looses power. Pull valve cover and find that the intake valve cap on cyl. #1 was stuck down inside the valve spring and the retainers are missing. Pull the head and valve is very bent but still in one piece! Contacted piston once and then it got shoved back and wedged into guide breaking the lip on the valve guide. WHAT HAPPENED!!!!!!!!!!!!!!!
Has anyone elso had this experience? The only mods are LT4 1.6:1 Rocker Arms, Valve Springs and Valve Caps. This is all factory parts on a LT1 engine (stock cam, etc.). The rev limiter is set at 6400 and I have been running it like this for about 6 Track Events. Was it a faulty valve spring cap? Did the spring bind? Did the retainers come off and the rocker beat the retainer down? By the way-the rocker arm is pretty beat up on that end. I don't know if I should just fix the bad parts and put it back together or make some other changes.

 

It's hard to say what happened without seeing the parts. The valve obviously didn't get pushed up by the valvespring when it was supposed to. Does the valvespring look okay or is it broken? If the locks pulled through the retainer then it's possible that the spring came up and the valve stayed down. What type of springs and retainers do you have? If you have the IRS/Racenet valvespring package with GMPP springs and mismatching retainers then I wouldn't be surprised with the breakage. Since you have self-aligning rockers it's also possible that you had retainer to rocker contact on the underside of the rocker and the interference caused the locks to fail. Check the rocker as well as the others and see if everything clears or if there are signs of contact. I'm not sure how you can inspect the piston without pulling the head, but the piston could be damaged. Someone locally here lost a piston from dropping a valve when their locks failed. Turned out to be a bad fit between retainer and lock I believe.

Good luck.

 

bent pushrod?

knock rocker over onto retainer, and walah-- dropped valve

or a keep just "broke"-
lots of bad things can happen at 6400rpms


anywya, that the modivational speech i got to spring for chromoly pushrods

 

In this case, and generally, not necessarily. When an engine sucks a valve, IF parts compatibility is not the issue, the locks simply let go. Not the first, won't be the last. Pick up the pieces and go from there. I can recall pulling covers, for valve lash adjustment and general check, finding valve stem(s) flush with retainers. Just a heartbeat/few cycles from 'sucking' valves right thru. No big deal, like I stated, (for oem locks especially) won't be the first.....

 

Yeah.....most likely keepers pulled thru. Im useing 10* locks and retainers instead of 7* (just be sure they are matched)

 

Miss-matched valve train parts can cause that to happen. Retainers, locks, valve stems come in a variety of sizes and types. If everything is not just right...zing goes a valve!