Strange exhaust sound
Thread Starter
3rd Gear
Joined: Jul 2012
Posts: 3
Likes: 0
Strange exhaust sound
I have a stock L48 with 44k miles with after market dual exhaust. Drivers side sounds great, but pass side has sort of a slapping sound out of tail pipe after reaching temperature. Lifters sound fine with no other noticeable valve related noise. I have replaced plug wires but sound continues. Car runs great with no engine related ticking. Not sure what's going on. Suggestions appreciated.
Race Director
Joined: Dec 1999
Posts: 11,094
Likes: 990
From: Sierra Foothills CA
Are you running the stock exhaust manifolds? If so, if memory serves me correctly the heat riser is on the right side. Have you checked to see if it's working properly? If that checks out you can pull plug wires off on that side one at a time with the engine running. Be careful not to get shocked- that'll get your attention in a hurry. If you have a problem cylinder this can help you isolate it by seeing if there's a plug wire that makes little or no difference when it's disconnected. From there you can see if it's a bad spark plug or something else such as a valvetrain issue. Good luck with it.
Burning Brakes
Joined: Mar 2012
Posts: 871
Likes: 73
From: Memphis Tennessee
A burnt valve will cause a funny sound in the exhaust. It will cause air to be pulled back into the exhaust whenever the piston in the afflicted cylinder goes down. Put a piece of paper behind the tailpipe. If it gets blown out and then sucked back in, it's a leaking valve. Then do a compression/leak down test on that side of the motor to find the bad cylinder.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
A burnt valve will cause a funny sound in the exhaust. It will cause air to be pulled back into the exhaust whenever the piston in the afflicted cylinder goes down. Put a piece of paper behind the tailpipe. If it gets blown out and then sucked back in, it's a leaking valve. Then do a compression/leak down test on that side of the motor to find the bad cylinder.
Keep the shiny side up!
Scott
Burning Brakes
Joined: Mar 2012
Posts: 871
Likes: 73
From: Memphis Tennessee
Hmm. Don't think so, but you could always block on exhaust tip and test the other. You just won't be able to tell which bank of cylinders it's coming from. The first time I saw someone do this test it was on a V6 toyota pickup with a 2 into 1 exhaust.
Thread Starter
3rd Gear
Joined: Jul 2012
Posts: 3
Likes: 0
Strange sound
I have tried the paper test and there does not appear to be any major sucking and both sides of exhaust are behaving the same, even though the one side has more of the puffing sound. I also just adjusted the lifters and no change.
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