Popping Sound through Exhaust

[Jack O.]

My '69 has a "background" pop-pop-pop through the exhaust at idle. I have '69 sidepipes so it's very pronounced. Does this indicate a leaking valve or something similar? Don't remember if it's on both sides but it's definitely on the driver side.
Thanks,
Jack

[Joe L.]

Re: Popping Sound through Exhaust

My '69 has a "background" pop-pop-pop through the exhaust at idle. I have '69 sidepipes so it's very pronounced. Does this indicate a leaking valve or something similar? Don't remember if it's on both sides but it's definitely on the driver side.
Thanks,
Jack

Jack------


Do you have an operating AIR system?

[Dick W.]

Re: Popping Sound through Exhaust

Put your had near the exhaust and see if it keeps pushing against your hand or does it allow your hand to go back toward the pipe,IE pressure against your hand, and it almost seems that it sucks your hand back toward the pipe, on occasion.

[Jack O.]

Re: Popping Sound through Exhaust

Joe,

No AIR system. Exhaust manifold holes are plugged - bought them that way.

Jack

[Jack O.]

Re: Popping Sound through Exhaust

Thanks. I'll try that. If it does not keep pushing what does that indicate?

[Dick W.]

Re: Popping Sound through Exhaust

Thanks. I'll try that. If it does not keep pushing what does that indicate?

Dead cylinder, could be plug, wire, valve, etc At least you will know which side to start looking for the problem

[Stuart F.]

Re: Popping Sound through Exhaust

If you have a dead cylinder, wouldn't you also notice a loss of power? Also, does it only occur at idle or would you also notice at POT or WOT?

Stu Fox

[John D.]

Re: Popping Sound through Exhaust

I would also see if you have the popping right after a run on the highway...if not that could indicate plug fouling at idle

[Doug M.]

Re: Popping Sound through Exhaust

carb set to lean will do that

Doug

[Jack O.]

Re: Popping Sound through Exhaust

Thanks for the responses everyone. Another "symptom" is that when I first start the car it simply reeks of gas fumes (it's an L71 however not with the original cam and with 1x4), compression very low because it was originally built with 6-71 blower). If I start it in the garage even with the windows and doors open my clothes and hair will also reek of gas fumes. Could this somehow be correlated with the popping as a clue to what the issue is?

I read on the net about leaks at the exhaust manifold causing a popping. I certainly don't hear or feel any apparent exhaust manifold leaks.

[Thomas H.]

Re: Popping Sound through Exhaust

carb set to lean will do that

Doug

Had this problem on my 60, but it was an overly rich mixture causing it. Metering rods in carb were not fully seating at idle.

Tom