JonB
03-11-2004, 02:59 AM
I installed a pair of cutouts in the exhaust system of my 1969 Firebird last weekend.
I started out with my TA Performance 3" exhaust, to which I added an H-pipe last year. The crossover really helped to keep the noise level down, which was the goal in the first place.
The exhaust system as I started (this picture is actually from last year):
http://www.offline.org/~burch/firebird/hpipe2.jpg
I completely removed the exhaust system from the car because it sits fairly close to the floor and I didn't really trust myself to do the work from underneath with the car up on jackstands.
I started by welding a couple of braces to keep the system aligned as I cut it into little pieces. I then marked and cut out a section for installing the first cutout, and chopped off half of the "H" so that I could attach it to the cutout.
Fitting the H-section to the cutout turned out to be the biggest pain. Basically lots of grinding and shaping to get a good fit. After I had it the way I wanted it, I traced the outline of the fishmouth, drilled a hole with a 2" holesaw, and ground the hole to size/shape using a carbide burr on a die grinder.
I did the work in halves to make sure everything stayed in alignment as much as possible. Here's a shot after the first side was done:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20001_640x480.jpg
The 1x square sections are scrap metal that I used as braces.
A shot of the nearly straight shot out the cutout:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20002_640x480.jpg
The other side went exactly the same, except the H-section decided to be a real bitch.
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20003_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20004_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20005_640x480.jpg
Now, if I'm lucky, it'll still bolt up to the headers when I get the motor back in the car.
Total cost was around $60 for the two cutouts. Time invested was about 4 hours, including beating the system off the car with a mallet.
When I was done I painted the whole thing with Krylon BBQ paint:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20006_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20007_640x480.jpg
It's drying in those pictures which is why it's blotchy.
The welding was interesting.. both the cutouts and the exhaust system are 16awg. I think the exhaust system is aluminized. I sanded it down to shinyness with a Roloc disc but it still wanted to burn through. I had to move REALLY quick and the end weld actually turned out very nice looking and pretty flat all things considered. I'm still getting used to working on round stuff--it's difficult to keep an even amount of stickout as you move your way around the tubing. There are a couple of spots where I screwed the pooch to some degree and ended up with the bead a little higher than elsewhere, and some spots where I had to fill holes that I had burned through, but at least I think I've finally got the hang of restarts.
Overall for exhaust welds I'd say they look pretty good ;)
I started out with my TA Performance 3" exhaust, to which I added an H-pipe last year. The crossover really helped to keep the noise level down, which was the goal in the first place.
The exhaust system as I started (this picture is actually from last year):
http://www.offline.org/~burch/firebird/hpipe2.jpg
I completely removed the exhaust system from the car because it sits fairly close to the floor and I didn't really trust myself to do the work from underneath with the car up on jackstands.
I started by welding a couple of braces to keep the system aligned as I cut it into little pieces. I then marked and cut out a section for installing the first cutout, and chopped off half of the "H" so that I could attach it to the cutout.
Fitting the H-section to the cutout turned out to be the biggest pain. Basically lots of grinding and shaping to get a good fit. After I had it the way I wanted it, I traced the outline of the fishmouth, drilled a hole with a 2" holesaw, and ground the hole to size/shape using a carbide burr on a die grinder.
I did the work in halves to make sure everything stayed in alignment as much as possible. Here's a shot after the first side was done:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20001_640x480.jpg
The 1x square sections are scrap metal that I used as braces.
A shot of the nearly straight shot out the cutout:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20002_640x480.jpg
The other side went exactly the same, except the H-section decided to be a real bitch.
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20003_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20004_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20005_640x480.jpg
Now, if I'm lucky, it'll still bolt up to the headers when I get the motor back in the car.
Total cost was around $60 for the two cutouts. Time invested was about 4 hours, including beating the system off the car with a mallet.
When I was done I painted the whole thing with Krylon BBQ paint:
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20006_640x480.jpg
http://www.offline.org/~burch/firebird/exhaust/Cutouts%20007_640x480.jpg
It's drying in those pictures which is why it's blotchy.
The welding was interesting.. both the cutouts and the exhaust system are 16awg. I think the exhaust system is aluminized. I sanded it down to shinyness with a Roloc disc but it still wanted to burn through. I had to move REALLY quick and the end weld actually turned out very nice looking and pretty flat all things considered. I'm still getting used to working on round stuff--it's difficult to keep an even amount of stickout as you move your way around the tubing. There are a couple of spots where I screwed the pooch to some degree and ended up with the bead a little higher than elsewhere, and some spots where I had to fill holes that I had burned through, but at least I think I've finally got the hang of restarts.
Overall for exhaust welds I'd say they look pretty good ;)