AIR PUMP

[Guest]

Can anyone tell me why exactly is the air pump pumping air into the cylinders for? Can it be totally by-passed???

[Sgt Art]

The air pump doesn't pump air into the cylinders, it pumps some air into the exhaust gas as it leaves the engine. The idea is to obtain complete combustion of the air/fuel mixture so as not to pollute the atmosphere with hydro-carbons. So, by blowing some fresh air into the exhaust, you are helping the burning mixture burn more completely. This is really important at higher RPM ranges due to the exhaust coming out still burning. It's like blowing on a glowing ember to make it flame. Further own stream in the exhaust pipe is the catalytic convertor which is nothing more than an afterburner that also assists in burning unburned fuel. You would think it all burns in the cylinder, but it doesn't. Get behind a rich burning car and you'll smell the unburned fuel mix. The air pump drains very little (if any) HP from your engine. If you turn one by hand, you'll see what I mean. The biggest problems with lost HP is the restrictive heads, exhaust manifolds and pipes that slow the flow. That and retarded timing (I'm over simplifying here, because I don't fully understand it all and books can be written on this subject) and lowered compression ratios are what really pulled HP down on most engines.

I would not recommend removing it if you car is EFI, it will play heck with your fuel mixture. If your state inspects for emmissions, you'll also be in a bind. As previously mentioned, removing it will not help your HP any.

[bwalat]

Keep in mind that around 1974-6 that some manufacturers made different setups for different markets, e.g. California. Cars that took regular and unleaded just had an air pump. Cars for unleaded fuel only had converters with or without an air pump. When unleaded fuel became commonplace and when leaded was eliminated, it became a nonissue, except in some parts of the world where it is still used.

I also have been told that one of the side effects of these gizmos was to reduce the parts per million (ppm) of smog that came out, as the extra air duluted the exhaust mix and ppm of pollutants to air is how pollution is measured. So, either way, the automakers made Uncle Sam happy and saved the planet with the available technology. It wasn't until EFI came along that power, fuel economy and pollution control problems were dealt with effectively.

BTW, if your air pump is making a clicking noise, you need to fix or replace it.

[Guest Albert]

As well in some designs it also helps to cool the exhaust valves, making them run cooler..Had a Mustang and the air pump exhaust, the PO had removed the pump ans it started burning oil as the valve guide seals at the top got too hot and leaked, replace them and the air pump, no more burning oil..