Side Pipe Muffler

[pgermond]

After replacing a blown header/exhaust manifold gasket and repairing (I hope a small radiator leak), I got the car out today (sorry - it was 65 here this afternoon). Everything went as planned - no exhaust or water leaks, so it is time to hit the road. I noticed some popping when I backed off the throttle on my way out of the neighborhood to the highway, but once I jumped on the highway and backed off the accelerator it was like the was no muffler at all!!! Pop-Bang-Pop-Pop-Bang.... and I'm thinking, WTF??? Did I blow some baffles out of the muffler or what? It sounds great accelerating but when there is back pressure it sounds like a war zone?

Any idea what happened and/or how to correct it without buy new mufflers?

[Jim Harding]

Phil, although I've not experienced it, I've heard that a leaking exhaust gasket can cause what you're hearing.

[pgermond]

Phil, although I've not experienced it, I've heard that a leaking exhaust gasket can cause what you're hearing.

I hope that isn't what it is because what I went through to replace that gasket was a $#@*&^!!!!

[JeepSnake]

Phil, Jim's right. Suspect a header leak or a carb that's crept out of adjustment and is lean on the idle circuit.

Exhaust popping is generally extra air getting in, causing combustion in the pipes during the momentarily rich conditions of deceleration.

I leaned the idle out a little too much on the FIA before Pigeon Forge last year, and had it popping like a $10 Saturday night special on decel. On my old Jeep, the manifold to pipe donut would vibrate loose, and it would pop on decel as well.

Prof. von Studebaker says your leaking header gaskets are karma for rubbing all our noses in your 65 degree weather!

[pgermond]

Damn-damn... double damn!!!! I did notice some minor popping just before I discovered the blown "paper" gasket. I used a copper replacement - I'm really surprised it is leaking........ and leaking as much as it is

[pgermond]

Prof. von Studebaker says your leaking header gaskets are karma for rubbing all our noses in your 65 degree weather!

I did say I was sorry when I described the weather (tell your Dad "hi" for me)....

[Slither]

Prof. von Studebaker says your leaking header gaskets are karma for rubbing all our noses in your 65 degree weather!

I hope the 'ol professor is doin' well these days. I miss hearing about his escapades. Is he off to do any secret agent stuff these days, or was the change of administration too much for him to handle?


Ya, Phil... karma...

[Naumoff]

Phil, re seal The sidepipe to header joints first. Obviously easier. Did you use the Permatex high temp copper gasket sealer with the new header gaskets?

Also do you have a solid lift cam and have you adjusted the valve lash recently?

[pgermond]

Tony,

Nothing on the gasket. I replaced the opposite side last year and didn't have a problem. Normally, if there is an exhaust leak I can hear it. I'll do some further investigation today..... and look at the collector-to-side pipe flange.

Thanks all for your input so far

[spd4me]

Had the same problem with my FIA 396W couple years ago. They seem to blow out at the back. When the engine is running, you can try to move your hand around to feel and air blowing out. I purchased a set of copper gaskets but the holes were oval and too small, took them back. I got a Holley double alum. square holes that matched perfect. Had to tighten a couple times but they wok great.
Bob

[spd4me]

By the way, whats up with the time clock on the forum. Post says 2:55 pm and it's actually 9:00 am?

[RJacobsen]

By the way, whats up with the time clock on the forum. Post says 2:55 pm and it's actually 9:00 am?

Go to quick links, user control panel, and choose edit options to set your time zone.

[weaver]

The muffler is similar to a glass pack but with stainless, I don't think you can blow it out. Sounds like an exhaust leak.

Alan

[pgermond]

Well, I'm biting the bullet..... ordered SCE copper gaskets yesterday from Summit, should be here Wednesday. Working on the driver side header of a big block in these cars is my least favorite thing to do

[Naumoff]

Phil, Hire a Carny. Small hands.

[davebetts]

I had this problem, years ago and it was definately a bad header gasket. Very difficult to work on due to the big engine and very little room for your hands and a wrench. I used a Gear wrench and went slowly. Don't forget to retighten after a few heat cycles, as the header bolts will turn in more after the first ride and cool down - takes about three heat cycles and they're good to go. Problem never resurfaced, not even after road raceing (very hot temps). I used standard FelPro gaskets. I bought coopers , but haven't had a reason to use them. Good luck, go slow.

[pgermond]

Definitely an exhaust leak..... of major proportion! Looks like an installation issue. I'll be much more careful when I install the new one tomorrow. Interesting - I didn't have this problem with the opposite side last year

[pgermond]

Mission Accomplished

A tip - when someone is helping you, be sure to back track and check everything twice.

[Slither]

Glad you got it fixed Phil... now go enjoy it!

[pgermond]

Glad you got it fixed Phil... now go enjoy it!

Thanks - that is exactly what I plan on doing this morning