sidepipe popping
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Joined: Jul 2012
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From: Bossier City Louisiana
sidepipe popping
Anyone have this problem? I installed a 535 hp 383 stroker In my 64. The sidepipes are now popping at idle. The popping overrides the normal exhaust sound. It smoothes out after idle. Thought it could be compression. It is only 9:9 compression though. I can't stand the sound. Guess I'll have to change to under car exhaust. Chime in if you have had this problem. Jackie
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That's unburnt gas lighting off in the exhaust. Could be a lot of things (I doubt its compression):
Lean mixture, not enough backpressure for that engine via the sidepipes or exhaust manifold leak (not likely if its doing it on both sides though) - in VERY rare cases bad vacuum brake booster.
Lean mixture, not enough backpressure for that engine via the sidepipes or exhaust manifold leak (not likely if its doing it on both sides though) - in VERY rare cases bad vacuum brake booster.
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From: Bossier City Louisiana
Not brake booster, don't have one. not manifold exhaust leak. Could be not enough backpressure. Smoothes out as soon as you give it a little gas. Might also be a little rich. Anyone else that's had a problem like this? Thanks for info Jackie
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I had that problem with my '67 but it did it on acceleration, not at idle. And you're right, the popping is obnoxious. I was also getting awful gas mileage (4-5 mpg) and lots of black sooty stuff coming out of the pipes and depositing on the body behind the wheels.
My carb was in bad shape, too bad to rebuild so I replaced it with a new Holley and converted over to electronic ignition at the same time. Car runs fine now, no popping at all.
Good luck,
-- Steve
My carb was in bad shape, too bad to rebuild so I replaced it with a new Holley and converted over to electronic ignition at the same time. Car runs fine now, no popping at all.
Good luck,
-- Steve
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From: Bossier City Louisiana
mine has no soot or anything. Runs fine, you can hear the normal exhaust notes from sidepipes but with a pop , pop , pop. its not a backfire or anything like that. I may unhook from headers and see if it still does this
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Put a vacuum gauge on it. Refer to this link for interpreting the readings. Valve problems could be the possible cause of your popping.
http://www.secondchancegarage.com/public/186.cfm
http://www.secondchancegarage.com/public/186.cfm
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Try adjusting the idle mixture on the lean side. Instead of trying to center the adjustments between the lean roll and the rich roll, adjust it just shy of the lean roll. I remember posts on here before with popping exhaust on decel with the throttle closed that were resolved with adjusting the idle mixture. At least it doesn't cost anything to try it.
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From: Bossier City Louisiana
I'm still thinking side pipes with this motor. I have new complete new motor,everything but block. checked valves, vaccum, we even changed carbs from new quickfuel back to holley 750 double pumper with no change. It doesn't pop when letting off throttle only at idle. Jackie
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From: Kingwood Texas
Put a vacuum gauge on it. Refer to this link for interpreting the readings. Valve problems could be the possible cause of your popping.
http://www.secondchancegarage.com/public/186.cfm
http://www.secondchancegarage.com/public/186.cfm
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From: Bossier City Louisiana
a sticky valve wouldn't do it out both sides. also it did it with two different carbs. but could still be mixture. I had one of the best carb guys in my town adjust.the carb. The timing is 38 1/2 if my memory is right. It had a stock 327 with a tuned port in car with I bought it. I had NHRA prostreet racer build, tune and dyno the engine.