Popping Exhaust
Thread Starter
Instructor
Joined: May 2006
Posts: 118
Likes: 0
From: Sydney NSW
Popping Exhaust
Had a 290 crate motor installed around 16 months ago (6000mls), had to have the heads re worked as the incorrect seals had been installed and subsequently damaged. The popping sound through the exhaust I had from day one continues. Just had a dual exhaust system installed and the popping is clearer and predominantly drivers side bank of exhaust.
I had a similar noise from the previous motor which eventually burnt out valve seals.
I have been told it could be the Holley and should look for a Rochester quadrajet!
Could be a lot of things.
Is this a common sound and/or most likely the sign of a fundamental issue, again!
I had a similar noise from the previous motor which eventually burnt out valve seals.
I have been told it could be the Holley and should look for a Rochester quadrajet!
Could be a lot of things.
Is this a common sound and/or most likely the sign of a fundamental issue, again!
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Had a 290 crate motor installed around 16 months ago (6000mls), had to have the heads re worked as the incorrect seals had been installed and subsequently damaged. The popping sound through the exhaust I had from day one continues. Just had a dual exhaust system installed and the popping is clearer and predominantly drivers side bank of exhaust.
I had a similar noise from the previous motor which eventually burnt out valve seals.
I have been told it could be the Holley and should look for a Rochester quadrajet!
Could be a lot of things.
Is this a common sound and/or most likely the sign of a fundamental issue, again!
I had a similar noise from the previous motor which eventually burnt out valve seals.
I have been told it could be the Holley and should look for a Rochester quadrajet!
Could be a lot of things.
Is this a common sound and/or most likely the sign of a fundamental issue, again!
I would try to find out which cylinders on the left bank are not burning completely and why. Start by pulling your spark plugs and look for wetness from fuel on the tips and also read the plugs for rich mixture as indicated by black sooty residue. Pull them one at a time and mark which cylinder they came from.
cc
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Pro
Joined: Dec 2008
Posts: 531
Likes: 0
From: Frisco TX
I come from the motorcycle world but the fundamentals are the same.
Popping on decelleration (as in several in a row) is caused by a lean condition - it will be very pronounced when you back out of the throttle after hard accelleration and can be compounded by muffler selection.
A single loud pop (more like bang) can be caused by a rich condition - as described above - but it is usually one loud bang as the excess unburned fuel ignites in the exhaust system all at once.
What type of mufflers are you running and how long since the carb has been tuned?
Popping on decelleration (as in several in a row) is caused by a lean condition - it will be very pronounced when you back out of the throttle after hard accelleration and can be compounded by muffler selection.
A single loud pop (more like bang) can be caused by a rich condition - as described above - but it is usually one loud bang as the excess unburned fuel ignites in the exhaust system all at once.
What type of mufflers are you running and how long since the carb has been tuned?
Melting Slicks
Joined: Jul 1999
Posts: 3,030
Likes: 17
From: White Pine / Dandridge TN
After I installed vortec heads I had a popping problem for several years. I thought it was my carb. I finally took the time to diagnose the issue and found that one of my exhaust gaskets was not sealed properly. I replaced it and the popping went away.
Jim
Jim
Thread Starter
Instructor
Joined: May 2006
Posts: 118
Likes: 0
From: Sydney NSW
Thanks all,
The popping is really only audible on idle particularly on start up and early stage accelleration, I have not heard it on decelleration or while cruising.
The Holley has been tuned to leaner side but hasn't been properly tuned for a year or so and not after head rebuild.
Week end start up often produces a cloud of blackish blue smoke and has produced the odd backfire.
Sounding more like a carb issue?.
The popping is really only audible on idle particularly on start up and early stage accelleration, I have not heard it on decelleration or while cruising.
The Holley has been tuned to leaner side but hasn't been properly tuned for a year or so and not after head rebuild.
Week end start up often produces a cloud of blackish blue smoke and has produced the odd backfire.
Sounding more like a carb issue?.
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