Projects Getting that Exhaust Sound Just Right

Don't move 'em. Let them break in. Packed mufflers are a totally different animal than a baffled muffler. The note and sound level will change as it wears in. Baffled mufflers don't do this. I saw a split 6 with glass packs start mellow and tame then after some miles it was the cackle master. Even steel pack mufflers deteriorate with carbon build up and use. I have a Borla on my Ranger and it changed over the years.

Let it run it's course. Trust me. I've run them all my life. They get louder and more aggressive with use.

 

Thanks so much, that is great to know. I will follow your advice and leave them alone and let them break in. I have more urgent things to take care of on that car.

 

Louder and more aggressive as they wear out? As they get closer to the end of their useful life?

 

Louder and more aggressive as they wear in?

 

Shoot.. who remembers shoving a straight piece of pipe up through the whole muffler? Instant loud...

 

The wrecking yards showed me how others did it, even former motorcycle exhaust shields
can be useful. Use some thread anti-seize and later you'll be able to adjust or remove pieces.

 

Thanks. Motorcycle exhaust shields seem like they could work.

Also, what about some sheet metal about 12 inches length x 6 inches width of a certain thickness (not sure what thickness) that I can bend to a 5 inch radius on a vice and bend a 90 degree flange on the end and bolt to the floor?

 

I wonder if something like this could work. I don't know what type of material was used. Anyone have a clue?

 

You can put a heatshield directly on the exhaust like that photo you showed, but I would prefer your first idea which is to put the shield midway between the pipe and the master cylinder. It will do a better job of blocking the heat if it doesn't actually touch the exhaust.
And like everybody else including you is saying, either reroute those brake lines or replace the master cylinder to get the lines on the other side. it is just too darn close - The longer you drive the car the more the heat will build up, and at some point your brakes will be dragging.
Once the line is a little farther from the exhaust, you can also put a heat sleeve over it. I have something I got from Summit or jags that Velcro's over lines on one of my brake lines.


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Thanks for the advice. I'm going to measure the lines and go to NAPA and buy the green bendable stuff and reroute. Am I being impractical leaving the master cylinder alone and fabricating the heat shield to sit midway? I know some suggested replacing with a master cylinder that has lines coming out the other side instead.

I will look for the heat sleeve stuff that Summit sells.

 

If you are going to reroute the brake lines why not just remove that master cylinder and bring it to the auto parts store and have them match it up with one that has the fittings on the other side that will bolt rite up so you don't have to do any fab work. Plan on not driving the car for a few days while you sort out your problems one at a time. Jack the car up as high as you can so you can work on it comfortably. Be sure to use jack stands also. Then you can run your new brake lines without doing it twice, put your heat shields on and correct any other things that need to be addressed while you are under there. With an old car it's always something!

 

And by the way if you follow any of my advice and of others who have been down this road before, check your 3 flexible rubber brake lines as well. Even if they look good from the outside they may be deteriorated from the inside. As long as you will be opening up your brake lines now is the time to check everything brake related. Remember that you didn't build this car so it is up to you to check that everything is done correctly. You can only blame the previous owner for so long and it seems to me that he has taken many short cuts from what I've seen already. Good luck son.

 

Thanks for the suggestion. If I'm going to replace the master cylinder and brake lines, I might as well think about other brake related questions I had a while back. I don't see any proportioning valve or residual valve and it has 9" rotors with that pinto setup. Instead of just replacing the master cylinder and and rerouting lines, should I add anything, and should I switch to 11" rotors and bigger calipers or will I not see much improvement? I had another thread open from a while back regarding the brakes. The car is hard to stop downhill.

 

Look at you, you've already fixed your transmission shifting problem all by yourself by reconnecting the vacuum line. Now just get a 30 pack of beer and a couple of pizzas and invite Special Ed & OzyRodder to come over again to go over the car with a fine tooth comb.(Before the beer of course) I'm sure they know what to look for. Seems like your gaining on it with their help. Wish I was closer to ya. Glad to see that you didn't need to modify the crossmember for the exhaust. Relax, things will work out if you have a plan.

 

Thanks that's a great idea but I'm probably going to have to make a lot more progress before OzzyRodder looks at the car again since he gave me advice on things to take care of but I just barely got the exhaust done from being so busy with work, etc.

At first Special Ed definitely gave me more confidence I could solve all the issues, and he helped me fix the airbag leak, but for completely legitimate reasons, he doesn't want any more involvement mostly because of safety related things he pointed out to me (I guess the tank mostly and wires passing through the firewall without grommets) and getting involved deeper with the car. A lot of things weren't done right on this car, not my fault really but definitely my fault for not looking closer when I bought the car... but I had no idea what to look for and the price was pretty reasonable.

 

Look at any heat shields that would modify into your plans. Also stainless steel is useful in 20 or 18 ga.

 

I thought you already ordered the grommets. That's what pissed off OzyRodder in the first place. If you can't put the grommets in by yourself then you shouldn't even be in this Hobby! Everyone buys a car that needs some attention or things that must be corrected. You're not alone. Your profile states you are an Engineer.

 

Haha. SpecialEd pointed them out first, but I think the tank is what worried him the most. OzzyRodder said I had far more important things to worry about before grommets.

Grommets already ordered and I can do those myself with my eyes shut and even redo all the wiring if I had to (I have equipment at home to do full PCB solder rework, and all sorts of wiring tools that I've used to build custom sonar systems that go full ocean depth).

I'm not fully confident in metal fab, at least not on cars and also don't want to spend a fortune on tools since I just bought my first house earlier this year, and like the car there are lots of things to take care of on that end.

I have used mills/lathes, etc in my past to build pressure housings but never welded much (just used a MIG welder a few times to learn and help my friend but that was 10 years ago).

 

I'm not reading all 4 pages of this muffler thread right now, but seems to me, if shields are necessary to divert the heat from the floor and interior, then the exhaust system is mounted too close to the floor.
I've had a BUNCH of cars, over the years, but none had the need for shields mounted to the mufflers.

 

Thanks. It get's a little hot in the cab after driving for a while but it's bearable once I get the fresh air tube. The brakes felt fine even after driving 45 min but I want to be on the safe side and reroute lines and shield the M/C.

 

Excellent idea.................new pipes sound good.

 

My jeans feel the best one wash before they die. Wore out, wore in--it's a fine line.

My brother turns his glass packs backwards when he installs them to defeat the airflow and gets instant loud.

 

Sounds like tools are a necessity now.

 

Yea basically I bought the car thinking my very basic toolbox would be enough to take care of small things but last year, I didn't have the eye to notice certain things like the trunk floor, etc etc... I am planning to take an adult education class in welding since it can't hurt. I guess with time I will buy more serious tools I need for metal fab.

The company I work for contracts a lot of metal fabrication to a guy who does throttle bodies and a lot of other miscellaneous car stuff and I'm pretty sure he'd be willing to help me out since I've sent a lot of business his way.

 

I meant tools for the house and car.

 

NOW will you listen...?

 

I'm slowly but surely accumulating more tools based on house projects I've had to take care. Car is starting to do the same.

 

Yea I know I didn't specify this to the exhaust shop. My course of action is to put aluminum foil over the M/C and brake lines and drive it back Saturday morning so they can shorten the chrome tips and reweld with a bump in the pipe so they sit higher up right along the bumper and just inside of it. Then its coming back home and going up on jacks for a while so I can reroute brake lines and make a heat shield.

 

About your rotor question: my car will lock up the brakes on the highway if I want it to, with the stock MII brakes & rotors. But I have a 1978 Impala power booster & master cylinder.
If your car doesn't stop well it's your master cylinder or your pads are worn out.
You might want to investigate master cylinders more before you go to a parts store. With your technical (non-automotive) knowledge you should be able to find one that will fit AND give you the flow & pressure needed to make the calipers do their job well.
Also, pull the wheels and check your brake pads & shoes! If that car doesn't stop well something is worn or incorrect or both.
(Having said all that, if it's a Pinto master cylinder and Pinto/mustang II brakes the combo should work, so maybe it's a lack of proportioning valve?)


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Thanks the car does stop but it's hard to make it stop downhill and I have to press on the pedal real hard. I am guessing maybe it is a lack of proportioning valve. I'm also used to a Chevy Astro Van with ABS and hydraboost so maybe it's just operator issues.

Here are some photos from another thread when I was working on replacing a shredded hose and redoing a hard line that stripped.. The brake pads are definitely fine. I also had the rear wheels off a month ago and the rear shoes looked plenty fine.

What size rotors do you have?