Strange exhaust sound
07-27-2012, 01:55 PM
#1
3rd Gear
Thread Starter
Member Since: Jul 2012
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
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.
07-27-2012, 03:29 PM
#2
Race Director
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.
07-27-2012, 10:03 PM
#4
Burning Brakes
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.
07-28-2012, 02:21 AM
#5
Le Mans Master
Member Since: Mar 2008
Location: Oxford MA-----You just lost the game!!!!
Posts: 5,948
Likes: 0
Received 62 Likes
on
52 Posts
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
07-28-2012, 11:53 AM
#6
Burning Brakes
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.
07-28-2012, 05:51 PM
#7
3rd Gear
Thread Starter
Member Since: Jul 2012
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
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.