'85 ELECTRA S/W W/307 OLDS-EXHAUST

[Guest]

I HAD TO CUT THE SMALL PIPE THAT GOES INTO THE SIDE OF THE CAT. CONVERTER.<BR> IT GOES INTO THE HOSE/PIPE COMBO AT THE REAR OF THE AIR PUMP. <BR> APP.IT KEEPS THE CAT FROM GETTING TOO HOT.<BR> IS THIS PIPE A DEALER PART?<BR> THIS IS MY FIRST CAR W/ANY REAL POLLUTION<BR> GEAR ON IT.<BR> THANKS!

[rocketraider]

It's for air injection. The smog pump sends air to the exhaust manifolds and the catalytic converter to scavenge and burn any unburned hydrocarbons out of the exhaust stream. Each hose has a check valve in it to prevent hot exhaust gas from backflowing into the smog pump and burning it up. <P>These parts fail regularly enough that most GM dealers keep the check valves and air injection manifolds on the shelf.<P>It should be a dealer part if it hasn't obsoleted. Did you cut the hose or the actual nipple that sticks out of the cat? You may be able to make up a hose from bulk length emission hose.

[Guest]

I CUT THE METAL END(AT THE CAT) AWAY FROM THE CAT.<BR>I'M REPLACING EVERYTHING BEYOND THE Y PIPE.<BR> I THOUGHT I WOULD REMOVE THE HOSE FROM THE REAR OF THE AIR PUMP AND TRY SEPARATING THE STUMP FROM THE CAT PIPE ON THE BENCH.

[NTX5467]

If I understand what you did, you did a big "KERWHOOOOPS"!<P>The air management valve can send air pump air to three places -- the air cleaner, the exhaust manifolds, and the catalytic converter. In combination or individually depending on the operational mode of the engine. As stated, it sends air to the catalytic converter for a reason and one that could result in your vehicle not passing the visual inspection for emissions equipment.<P>You can buy replacement aftermarket converters to replace the factory converter that have those pipe nipples already made onto them. Use only steel pipe to connect to the converter due to the fact that it gets very hot!<P>I believe there are now replacement air tube manifolds in the aftermarket now. Similar with the check valves. The pipe going to the converter might not be, though, as they typically caused no problems--unless some outside influence caused them to break.<P>You can find the replacement ceramic monolith (honeycomb) converters from various places. The Walker Dynomax site has information and specs--even an online catalog of sorts the last time I looked--so you can put a large pipe converter under there that is correctly sized for your application (engine size and air pump pipes).<P>Considering all of these things, there's no reason to not have a legally compliant exhaust system that also has good performance attributes.<P>NTX5467