i was driving down the road yesterday and my car all of a sudden started making a pinging noise and running very rought. i made it home.

i pull the valve covers and find that the exhause valve rocker on the # 4 cylinder is loose. i removed it and find that the spring is lower than it should be - about 1/2 inch lover than the other springs when the valves are closed. the car will turn over, did it with a pull bar.

do you think i have a warped valve? what about piston damage?

it is a 67 289/306. heads done recently...5000 miles ago

 

I dont think the valve is warped, maybe bent or just "stuck". Or possibly the valve spring is broken. Will the valve return to the closed position if you try to pull it up? If so, it is probably a spring, if not the valve is probably bent or really stuck in the guide.

Was the engine running at a high RPM when your problem started? (like redline or close to redline)

It will be hard to know if you have piston damage until the problem with the valve is known.

At this point, unless you are dealing with a known broken spring, you can pretty much figure on pulling off the effected head. The spring can be replaced without pulling the head if the valve has suffered no other damage.

 

i removed the rocker arm, and the valve is still down. it will not come up. which was the valve will not.

well, i was pulling out to pass a car on the 4 lane and goosed it a little, only about 3000 rpms, at about 70. i have a 3.00 rear.

the valve is definetly stuck down.

 

Sounds like a valve spring problem. Sorry, but you are going to have to pull that head and take it to a machine shop or do the work yourself.

 

i don't understand why it is a spring problem if the valve will not "pop" up when the rocker is removed. the valve is also very tight - it won't wiggle or move at all. seems if the spring was broken, it would move a little.

 

It is very difficult to diagnose through a computer monitor. Just take the head off and take it to a machine shop. If it is a bent push rod, then you need to determine what caused that. I would suspicion the timing chain has slipped a notch or two and the valve got bent. Like I said, hard to diagnose through a computer monitor.

 

i know.

well, if i've got to pull the head again - i may as well bit the bullet and get some new aluminum heads. i love the afr but don't want to spend the money. other than the afr, what's the best for the money for street driving. no junkyard, they will be new.

 

A scenario for this would be the valve did not close all of the way, the hydraulic lifter took up the slack, the valve opened up even more, got hit by the piston, bent the valvestem, and now it is stuck. (If I am right, a broken or weak valvespring probably did start the whole thing.)

 

Find out (google) what the difference in the price of AFR 165's and Edelbrock RPM's are.

 

Here, I'll getcha kick started.
http://www.edelbrock.com/automotive/headford.html