SC Engine Questions...

gosla · 05-30-2002, 05:01 PM

Hello all;

Started a repair job today to my 911 Targa (rear end damage). This is the first time I've examined the engine area very closely. It seems that a previous owner has messed with the emmissions systems. Bummer. I wanted to do that myself...

Anyway, there is a bypass pipe in place, rusted at the inlet. I intend to replace, but I'd like to be educated on what side effects one can expect with a rusty bypass pipe in general...

I noticed injector looking things under the heat exchangers that all connect to a tube, clipped and squeezed shut at an end. Effects?

Right hand heat exchanger is a bit loose. How does one know when it's time to replace? The header part seems fine. It's just the metal covering is loose somewhere. Not sure exactly where...

It's an 80 ROW Targa. It has a large stainless muffler, one pipe on the left out. What I don't understand is that the tip is steel and rusty. Not structurally comprimised, but rusty. Who would manufacture a stainless muffler with a mild steel tip???

I understand that pre '74 heat exchangers help. How do these compare to new, stainless, "tuned" systems offered today? I'm leaning towards Pelican Parts GHL system. What's the best system offered from Pelican?

Thanks so much in advance. Learning so much here...

Nicholas

MotoSook · 05-30-2002, 06:03 PM

Sounds like you need atleast one heat exchanger if you want good heat in the winter. As for a new muffler/exhaust...do a search on exhaust on this forum before you spend money. You'll see some very invent uses of lower cost products. Jack Olson has a custom exhaust system made with a Camaro 2-in 2-out muffler (I think that's right) that sounds great. You can do make a similar one with a 1-in 2-out muffler.

The cat-by-pass pipe is rusted, can might be able to be re-welded or just buy a new one. They go for a bout 120. biggers effect of a leaky pipe is a louder exhaust. I don't think you'd lost an appreciable amount of power.

As for the air injectors to the exhaust ports, remove them if you can and plug them more properly. I have brass bolts that I bought from NAPA for this task. The fit fine and look a heck of a lot better. I forget what size, but I can find out if you need it.

Jim T · 05-30-2002, 06:20 PM

If the bypass pipe isn't rusted all the way through, its fine. Its pretty thick usually - would be tough to rust all the way through.

The injectors are for the air injection system. I'd probably pull the clipped ones out and replace them with some plugs, which are available (PP probably has them). No harm in leaving the clipped off ones in place, the injectors are probably clogged up and junk by now, and are acting like plugs anyways. Putting proper plugs in would be for the sake of appearance.

If the sheet metal on the exchanger is just a little loose, no biggie. Most are by now.

I think for power purposes, the pre-74 stock exchangers are just as good as any aftermarket headers.

gosla · 05-30-2002, 06:38 PM

I have the muffler off and can see light when looking into where the muffler hooked into the bypass. Two tubes go in. Light is seen around the tubes. The whole thing is rusty. Strangely though, the bolts were stainless and came off easier than I could have hoped for...

Nicholas

Superman · 05-30-2002, 06:48 PM

Well if you can take a muffler off, then you can take a bypass pipe off too. I'd agree they are thick enough that they should last. Take it off and grind the mating flanges flat...perhaps it will seal up again. If it has holes, replace it. It must be making spitting noises now.

Wayne 962 · Wayne 962's Garage

We sell the stainless steel bypass pipe from GHL - nice piece of equipment. Also have the plain steel one for $130...

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_exhaus_main.htm

You just need to tack-weld your sheetmetal onto the flange on the headers...

-Wayne

gosla · 06-01-2002, 02:22 PM

Lost me about the tack welding. What exactly are you welding??? Thanks

Nicholas

Wayne 962 · Wayne 962's Garage

Tack welding:

"Right hand heat exchanger is a bit loose. How does one know when it's time to replace? The header part seems fine. It's just the metal covering is loose somewhere."

The sheetmetal is tack welded onto the header part from the factory. When this breaks loose, it rattles. Simply reweld...

-Wayne

fred cook · fred cook's Garage

Are you sure your car is an 80 model? If it is, it should have a single CO sensor in the cat pipe. The 78 and 79's used an air pump with fittings like you described (3 per side). Check your car's serial number to be certain what year it really is.

Fred Cook
80 911SC Coupe

1980SC · 12:38 PM

His car is a euro '80SC. There are a lot of differences between the US and euro 1980 911's. One of which is that ours came with smog pumps.

-Rob
1980SC euro