n_holman

I was doing some errands today and driving my '69 98 4 door hardtop that I bought Thursday. I was on the freeway at 65 going up a hill when the engine began to slow. It didn't miss but I had to keep pressing down on the gas peddal. It went kaabooom! My wife went hesterical. pulled over and looked under the car ad sure enough the muffler was split and the metal outter shell was dragging on the pavement. Obviously I know of several reasons begining with the fact that this car has sat much of the past 30 years covered in a garage. Just 2000 miles driven since 1985. (94k total) Something plugged up the muffler or tail pipe...maybe a mumified rodent.

Anyway now I need some suggestions to what kind/type of new muffler to get. I have a '71 Buick Centurion convertible with the factory performance 455 and dual Flowmaster exhausts. The Olds I want to keep kinda 'sophistcated'. No noisy duals but a single exhaust that will keep the exhaust flowin freely. The Olds will share towing our vintage Airstream. The Olds has a ressonator at the end of the exhaust. I believe this isn't a 'healthy' item to quickly allow exhaust to leave. What do you think?
Neil

z11375ss

First of all, I absolutely love that car. I am looking for something like that for myself. As far as the muffler, I think you have it right when you say perhaps something had clogged the pipe. Why not go to your local muffler shop and have the stocker replaced. Can't be too expensive and like you said it will stay executively quiet as it should be.

MDchanic

Far as I know, the only thing the resonator takes away is money, which is why muffler shops threw the old ones away and didn't install new ones.

I agree with z, get a high quality Walker or similar quiet OEM-style muffler.
If you think it's too restrictive, you can always run duals - it'll flow twice as well.

- Eric

MDchanic

Also, though an exhaust obstruction seems like a good idea in this case, I have never seen a muffler explode unless it was full of gasoline.

You should consider whether you have a condition that would lead to raw gas being pushed into the exhaust, such as no spark in one cylinder.

- Eric

ThePackRat

I wonder if the timing could have jumped to cause the loss of power & backfire.

olds 307 and 403

I hate micess to piecess! I am in the same boat with our Challenger. It is whisper quiet now but am thinking of swapping the single muffler to either a Dynomax Super Turbo or a Magniflow. Same goes for the Dakota, gutless at highway speed. Fit the largest muffler you can fit in there. Even without the resonator, it will be quiet. I am assuming you can fit a 24"+ long, large case muffler in there.

oldcutlass

All good suggestions above, I also have never seen a muffler explode due to a blockage. I would check ignition and carb thoroughly.

n_holman

Thanks for the helpfull suggestions. I've blown mufflers before...as a teen in the '50s by turning off than on the ignition....cool. More recently...if 15 years ago is recent....installing a distributer in 180* off in another Buick. That sent birds a flying for miles. This time I was driving up a hill at 65 when with no miss fires the car began losing power so I stabbed the accelerator. The engine runs good but the last service record was 2k ago in 1985. I know definetly that I should give it a tune up...especially new plugs and points. A routine sight check under the car when I got it showed a muffler seam begining to separate.
Neil

m371961

If it ran bad before it blew and ran well after, certainly points to an obstruction.
Engine may be a little rich.
My understanding of a resonator is that the exhaust passes straight thru. But that it creates a turbulance that affects tone and drone of the exhaust. On my 65 98 I am going to duels, factory type stock muffler with no resonator. If I think it is to annoying, a resonator would be easy to add in with the long tailpipe.
I prefer to travel in "Stealth Mode", and cutouts would be cool.

joe_padavano

Sorry, no. There is NO way an obstruction could have built enough pressure to rupture the muffler. The engine would have stalled out long before that point. The only way to explode the muffler is to have unburned fuel pool in the muffler then ignite. That's what happened. You have either a carb, ignition, or other engine problem. This may be as simple as a stuck choke or it may be a jumped timing chain. It is NOT a dead mouse.

Sampson

X 2 to Joe P 's comments. Obstruction = no power. Big boom = muffler full of gas. Have seen Cattalytic converters get so stopped the car would hardly move. One time I was coming through the mountains and the coil wire jumped outta the dist and then made contact blew athe muffs off and scared me to death.

Allan R

Others have already identified the potential cause of the problem. Olds put a resonator after the exhaust for a reason - to reduce noise. So if you want stock sound....

z11375ss

What if the mouse had a very small stick of dynamite. That could have worked. And he surely be dead now! It would be like Mouse Jihad!

MDchanic

We'll see if any videos appear with high-pitched voices claiming responsibility .

- Eric

m371961

Just stated what I have seen. Care less who believes it happened.

djcrook73

the last car i blew a muffler on had a leak in the exhaust at the head pipe to manifold and a rich carb(could smell a hint of gas when stopped, think i set the float too high when i rebuilt the carb) - floored it in second getting on the highway, and as soon as i let off, boom! (had this happen with more than one car and it was always right after flooring it. i have seen cars with clogged cats glow the pipes cherry red and no boom, so i agree with the other guys based on pure experience. double checking the carb and ignition components will probably give you a little more power and smoothness anyway so sometimes a bad event turns into a good thing later. good luck with it, nice ride

MDchanic

You only have one other post on this thread, and it doesn't speak of your having seen anything:
And that's no way to talk to your helpful fellow members.

- Eric

n_holman

I'm taking all opinions and suggestions seriously. Before getting a new muffler I'm installing new plugs and points/condenser. I don't believe it was the resonator as 2 holes had been punched in it and the tail pipe has seen better days. The car is running smoothly except for just before the boom. As I have mentioned already I have blown up a muffler before with too much raw fuel in the exhaust so I will give serious attention to perhaps a dirty carb. I dumped carb cleaner in the tank when I got the car Thursday. My friend who sold me the Olds drove it 50 miles through the foothills to come here. That's winding and hilly roads plus a couple straight stretches. Given that this car was driven only 2k miles since 1985....stuff happens.
Thanks again. I'll keep you updated.
Neil

MDchanic

Don't forget the ignition - if an engine is running rich, it will run poorly and smoke, but is very unlikely to fill the muffler with gas. If the float bowl is overflowing, it will barely run at all.
On the other hand, a momentary interruption of spark to one of more cylinders while the throttle is far open (such as driving uphill) can send a lot of unburned gas out the pipes. I'd also check the ignition, and especially the spark plug wires.

- Eric

Allan R

Neil, have you considered talking to Gardner Exhaust systems? They make one of the best systems available for fit and sound compared to OEM. I don't know if they have B/C exhausts but it wouldn't hurt to ask them.

z11375ss

Gardener may have mice in them being made in a garden and all. You know what will happen then! Jihad, Kaboom!

Allan R

???GARDNER not Gardener. Gardner makes one of the finest replacement OEM exhausts including original 'sound' on the market for a lot of brands.

Rocket331

I blew out the muffler on my '69 98. It was just the timing.

11971four4two

The garden exhaust guy told me to sell my NOS pipes and buy replacements there
WTF

n_holman

After reading ALL of your posts and considering my own long time car experiences with and with a dash of common sense I am now positive in believing that the reason for my muffler blowout is ignition failure. I am replacing the plugs, points, cap and wiring AND of course checking the timing. My Buick has occasional similar backfires even after tuneups including timing checks....unlike when I once installed a new distributor 180* off...that ruined a NEW muffler! My first car was in 1954 so you'd think I'd know better by now!

Neil

gs72

z11375ss Your mouse jihad theory is cracking me up!!!

n_holman

Laughter is very healthy.


Neil

Scooby

Good idea checking ignition. I had a backfire in my 71 Cutlass Supreme that blew the oval muffler round with a hole and a BOOM! on the highway. Turned out to be related to a grounding issue with the newly installed Pertrronix unit (the Pertronix are great - it was a wiring routing issue). Keep on along the lines of fine tuning/replacing components of the ignition - plugs, wires, etc.. Good luck, brother.

s i 442

Both my mufflers are exploded right now.
The Edelbrock carb back fired and thats all it took.
Now I get to by some "Pypes" exhaust.

jag1886

I used to work in a parts store back in the 70's and 80's and we saw this all the time, I'd say almost one a week and it was almost always a defective ignition condenser causing some plugs to fire at the wrong time. It would not fire some cylinders on time and unburned gas would build up in the exhaust system then it would fire one cylinder late and set it off. KABOOM and blow the whole bottom of the muffler out.

MDchanic

No.

The condenser has nothing to do with when the plugs fire or with which plugs fire.

When you have a failing condenser, ALL of the plugs will fail to fire for a moment, probably a revolution or two, causing raw gas to be pumped into the exhaust system, along with air (containing oxygen).
All it takes then is a spark from a cylinder that's firing again, and BOOM!

We used to do this when I drove ambulances: pump the gas a whole bunch of times while driving (preferably on a downhill), then immediately turn the ignition off and then on again -- BOOM!
Especially fun in a tunnel!

- Eric

nsnarsk65cutlass

Oh yes when the ignition condenser fails you will have exhaust backfire or explosion as stated.Back in the day i too would turn the key off and pump the gas pedal and turn the key on, but stock mufflers would only take one good backfire and you're done with those mufflers.I had glasspacks so i could do rapid fire and still have working exhaust if you want to call it that.This was in a 1968 396 caprice station wagon.