Burnt vlave on Big Block ???

INMYBLOOD · 04-22-2003, 02:14 PM

We are working on my brothers BB Chevelle it's a 72 402ss. We now believe the number 7 cylinder has a burnt valve. There is a flutter to the exhaust tone. There is no differance in how it runs at idle or reved with or with out this cylinder having the plug wire on. Tried different plug and wire no differance. This cylinders plug is fouled black also. The engine has always had a flutter to the exhaust tone. We have always thought it should run a little better. It will get a leak down test in the morning. I was just wondering if any of you have had this problem and if so how much different was the motor once fixed. I would really love to see this motor come alive for him. Thanks

andy60 · 04-24-2003, 08:48 AM

Gordon,

A simple compression test will let you know if you have a open or burnt valve problem.

If the compression test shows good then you may want to look at the cam (for a bad lobe) or valve train especially for a bent the push rod. Have you take the valve cover off? Can you get your hands on an old valve cover and cut the top off so you can run the motor and look at it?

But I am not telling you anything you do not know?

I know it is no fun running those problems down, good luck.