Exhaust Question

[Superman]

Really surprised and frightened. My new '79 RoW SC has what appears to be SSI's. They certainly look like SSI's, and that's what the PO thought they were. But........they don't fit my standard final exausts. They are fully a half-inch off. The exit flanges of the heat exchangers are not the same distance from each other. I believe they are too wide, but I don't recall clearly. I have two leftover final exhausts from my last car, and when I went to bolt one on, I found the fitment problem. A full half-inch.

The final exhaust on the car, which does seem to fit, is a name brand but I forget the name. The body of the muffler looks like it should be on a buick or something. It is rectangular of course, but from the end it is eliptical. Two pipes go in (from the heat exchangers) and above that, two pipes come out and down. Again, the body of this muffler looks like just about any eliptical-shaped muffler that might be on a Chevrolet, except it has two pipes coming in and two going out.

My fear is that this exhaust system is somehow proprietary, and that is why the flanges are not the correct distance apart. Ah well. In any case, I'd guess I need to modify my favorite exhaust (Triad West Performance) in order to put it on the car. I cannot imagine that my '79 Euro engine dimensions are different from my '83 USA.

Anybody know why I'm having this problem? Is this a Bursh? Are they made using proprietary dimensions? If so, I'm going to badmouth them ad infititum.

[rusnak]

it sounds like you have about 2-3 hours of work for a custom muffler shop. Those guys are so good with a torch and welder I don't think it's worth worrying over.

[Jadams1]

My 80 ROW SC has SSI's and a stock 2 in 1 out Danks muffler bolted right up.

[RarlyL8]

Knock-off SSIs do exist.

[Superman]

Okay, thanks. If anybody has more information, bring it on. I have a friend in the Porsche exhaust business so no, this will not be a big problem but it is a disappointment and a surprise.

[john walker's workshop]

those pipes on the SSIs are flexible. bolt on one side loosely and stick the sharp end of a crowfoot in the other and pull it sufficiently to get a bolt through.

[Superman]

Thanks, John.

[mb911]

yup deflection of almost an inch .. We send instructions with our muffler to indicate to loosen the HE if possible so to make the system as stress free as possible but you can pull them pretty good just like john says

[acapella8]

Post some pictures, I'd like to see what you have. . .

[Superman]

My old heat exchangers (from a '73), steel, also did not fit the final exhaust perfectly, but the difference was only about 1/4". Still, it was not easy to get those flanges to mate up. Perhaps the SSI units flex more.

But what bothers me is that SSI's are a quality product, my final exhaust is also a quality product tested over decades, and they SHOULD match. No reason for them to be exactly a full 1/2" off. That's ten times to allowable tolerace for a frickin' FRAMING CARPENTER for cryin' out loud. Let alone a precision German performance car.

[mb911]

Originally Posted by Superman

My old heat exchangers (from a '73), steel, also did not fit the final exhaust perfectly, but the difference was only about 1/4". Still, it was not easy to get those flanges to mate up. Perhaps the SSI units flex more.

But what bothers me is that SSI's are a quality product, my final exhaust is also a quality product tested over decades, and they SHOULD match. No reason for them to be exactly a full 1/2" off. That's ten times to allowable tolerace for a frickin' FRAMING CARPENTER for cryin' out loud. Let alone a precision German performance car.

It depends on what was used in the original mock up for fixturing. The ssi's move a bunch as the studs(in the head) allow for some movement as the holes in the flanges are larger causing for deflection.. You would be suprised the differences we have seen

[Superman]

Interesting. Thanks, Ben. I think I get it. When SSI's are installed onto the engine, there is a range of distances between the exit flanges that can be achieved just by HE positioning onto the exhaust port studs. Okay.

My final exhaust maker (I think you know who that is) and his predecessor have been making those things, using the same jig, for probably twenty years. There are no fitment problems. I assume your quality control is the same. SSI's are of the highest quality also. And so.....it was a little scary to see a full, exact half-inch difference.

[mb911]

Originally Posted by Superman

Interesting. Thanks, Ben. I think I get it. When SSI's are installed onto the engine, there is a range of distances between the exit flanges that can be achieved just by HE positioning onto the exhaust port studs. Okay.

My final exhaust maker (I think you know who that is) and his predecessor have been making those things, using the same jig, for probably twenty years. There are no fitment problems. I assume your quality control is the same. SSI's are of the highest quality also. And so.....it was a little scary to see a full, exact half-inch difference.

Yup you got it