Can anyone explain the purpose of the air pump.

[oldbimmers]

Installing a Tii motor (with carbs) into my non tii. Big ass air pump bracket is broken and won't fit the Tii block. What should I do?

Also should I use non Tii alternator support bracket on Tii block (planning to use non tii alternator).

[PSloan]

Are you planning on using the air pump? if so, Don't.

There are 2 theories regarding the air pump -

1 - it pumps clean air into the exhaust to make the ppm of harmful exhausts go down so it will pass emissions

2 - the added air makes and unburned fuel ignite and burn off in the thermal reactor

I dont know which is true - but both are useless.

[oldbimmers]

Great! So I don't need to look for the bracket.

Regarding the alternator, since I won't have an injection pump, I could run the alternator on top right? (And use the brackets I have)

[JohnN]

to keep them cooler. The early fix for emissions was to lean the crap out of the engine, frying the valves. The pump and the infamous 'gulp' valve were the first of several bandaids those lovable Germans used.

Yours for folklore and urban legends

John N

[Guest Anonymous]

I have limited experience with air pumps except that they had a terrible habit of making 70's GM cars sound impolite and terrribly restricted. I vaguely recall someone with a Camaro attempting to modify his airpump so that it supplemented his normally aspirated system. Kind of like a poorman's supercharger.

The concept sounded good, but I do not believe it was successful.

Good luck.

[jgerry2002]

Air pumps are still used on cars today to reduce emissions. They are not a "useless" tool.

They are used to reduce CO and UHC. Same principal applies here as well.

So the loveable germans were on to something, even if they were stubborn when it came to catalytic converters.

[ingraham]

and don't use much power. They merely pump some fresh air into the exhaust manifold; they don't 'restrict' anything.

Assuming you're doing this to a pre-1976 car in California, you don't strictly need the air pump.

A non-tii alternator mounted non-tii style is fine, and it will be more accessible for service.

[Guest]

If memory serves me Hot Rod modified the pump to pressure the air filter They had to write a mea cuppa