Popping out the exhaust

[clay37355 10]

Ive got a strange popping out of the exhaust. It doesnt do it while its idleing. I can rev it up in neutral and it never does it. it only does it when im going down the road. It will do it while cruising, under acceleration , and deceleration. Any ideas? I already replaced the plugs. Its almost like it will only do it when the car is moving. It sounds to me like its only coming out of the passenger side pipe. I was driving it tonight and unplugged plug wires one at a time to see if i could get the popping to stop. It didnt though. Kept popping out the one side no matter which wire was unplugged.Motor is 351w 393 stroker , MSD Box and dist. Demon 825 Carb. thanks for any help or ideas

[sportsroof69 13]

Are you absolutely positive you got the plug wires back on right, with the right firing order?

[Fordrevhead 29]

Im guessing a valve sticking open. Could be a lot of thing though.

[jholmes217 65]

Sounds like valves need adjusting. How long since the engine was rebuilt or cam installed. Anything that would require the rocker arms to be set?

[vettist 10]

in my ears a leakin exh gasket, common with over torqued bolts.

[clay37355 10]

Sounds like valves need adjusting. How long since the engine was rebuilt or cam installed. Anything that would require the rocker arms to be set?

 

Thanks for all the suggestions. I am going to check the plug wires and firing order tomorrow. Will also check the rocker clearance. The engine hasn't been in the car too long, Ive probably only put 2 or 3 thousand miles on it. Odometer doesn't work. It has a solid roller cam with scorpion roller rockers. Ive done one adjustment on the rockers earlier before the popping and have probably put 1000 mi on the car after the valve adjustment without the popping. Thanks again guys and ill re post tomorrow

Edited July 27, 2012 by clay37355

[MikeStang 247]

Sounds like valve stuck/ out of adjustment...check those rockers as well...I dont know much about the scorpion brand, but if your running a Solid roller with a goodly amount of lift i would DEFINATLEY have some stout rockers.

I had some CAT stainless rockers on the new AFR heads i bought as a package deal....After Dyno time ONLY i opened the top up and inspected the rockers....the rollers had black hot spots on them and the rollers were starting to gald, and my Hyd roller is not that big.

STAY AWAY FROM CHEEP ROCKERS....and always install adjustable push rod guider plates on AFR heads, their push rod alignment SUCKS.

Oh check all the push rods as well.

Mke

[jholmes217 65]

I had the same problem a couple weeks ago. I changed plugs, messed with timing until I wore the paint off the hold down bolt. I had one cylinder that kept fouling the plug. I figured since it was a new rebuild, it was just the rings not seated yet. Finally I did a compression check and walla! No compression on that cylinder. I re-adjusted all the rockers, and popping is gone and a lot more power!

[clay37355 10]

Well. I went through and checked my valve lash. I did find a few exhaust rockers a little tight so i reset them all. Took it for a spin and its still doing it..... I checked the firing order and everything is good there.. Im going to check the plugs. I may tighten the gap a little and see if it helps any too. Im running .050 now , but have ran that for a long time without the popping. Im hoping its not a burnt valve

[clay37355 10]

I checked the plugs and all looked good. Swaped all the plug wires from passenger side to drivers side. Still popping...May sound crazy,,,, Ive done everything i know to do. I checked under the rear of the car to make sure the exhaust wasnt loose and hitting something. I noticed alot of diff fluid on my rear wheel. Jacked the car up and see that my passenger side rear wheel bearing is shot... Am i crazy? could the popping im hearing be from the wheel bearing and not out the exhaust?? Guess that may explain why i only hear it when the car is moving..

[Boogerschnot 12]

Are you sure its not a pinging that you are hearing? Maybe try backing down your timing a tad, if it goes away you were detonating.

[Fordrevhead 29]

Well the bearing/seal needs to be fixed anyway. But do you feel a hesitation in the seat of your pants, loss of power when it pops? I had a weird noise on a Caravan I drove this week. It ended up being cheap hubcaps, lol

[clay37355 10]

Guys i think thats what it is . Its getting worse where ive been driving it back and forth. On the last trip it even squealed and then popped. ive had two other people ride with me and they said it sounded like it was coming out the exhaust.. ill replace it tomorrow and maybe get lucky

[LoneWolf2U 136]

I checked the plugs and all looked good. Swaped all the plug wires from passenger side to drivers side. Still popping...May sound crazy,,,, Ive done everything i know to do. I checked under the rear of the car to make sure the exhaust wasnt loose and hitting something. I noticed alot of diff fluid on my rear wheel. Jacked the car up and see that my passenger side rear wheel bearing is shot... Am i crazy? could the popping im hearing be from the wheel bearing and not out the exhaust?? Guess that may explain why i only hear it when the car is moving..

 

Are you crazy? :clown:... Can't answer that.

But the popping sound is echoing in the rearend housing so it could sound like its coming from the exhaust.