AIR Pump

[William P.]

Hi. Can anyone advise me how to take apart an AIR pump to remove the vanes . I have purchased a rebuilt one on line and it dosen't seem to come apart .

Bill

[William P.]

Re: AIR Pump

ttt anyone ?

[Jim T.]

Re: AIR Pump

I kept my original air pump from my 68 after installing a rebuilt one. I would of put new bearings in the 68's original air pump and continued to use it but could not find any information in the GM service manuals on how to do the bearing replacement. You might be able to get some information from someone that advertizes in the NCRS Driveline concerning the air injection system.

[Terry M.]

Re: AIR Pump

One of the Overhaul Manuals (NOT Service Manual) has the AIR pump rebuilding information in it. It is either 1967 or 1968, IIRC. I have a tight travel schedule, so I may ntobe able to look for a few days, but I can't be the only one with Overhaul Manuals for those years.

[Lawrence M.]

Re: AIR Pump

As Terry said there should be info on how to take apart and replace the vanes of the C2 AIR pump in the 1967 Overhaul Manual. However the C3 pumps were designed differently and the only service operation is replacing the front filter. I believe the C3 pumps can be rebuilt, but I do not know how to do it. The rear cover comes off the C3 pumps, revealing an access hole that looks too small to get the vanes in or out in one piece. Contact Bill Hodell. He advertises in the Driveline and I'm pretty sure he can rebuild C3 pumps.

[Lawrence M.]

Re: AIR Pump

Here is a picture of the rear cover removed from a 1969 AIR pump.

[Joe L.]

Re: AIR Pump

One of the Overhaul Manuals (NOT Service Manual) has the AIR pump rebuilding information in it. It is either 1967 or 1968, IIRC. I have a tight travel schedule, so I may ntobe able to look for a few days, but I can't be the only one with Overhaul Manuals for those years.

Terry-----

The overhaul procedure is covered in the 1967 edition of the factory overhaul manual. I don't know if it's covered in the 1968 manual. The C2 AIR pump is somewhat different than the C3 pump but the basics for overhaul are the same for both.

[Michael B.]

Re: AIR Pump

Two things. First you are not going to see any performance gains from removing the vanes from the pump. The system works with exhaust gas which has already passed through the power cycle in the engine. It simply adds a little bit of oxygen to the hot exhaust to aid in combustion of fuel that did not burn in the cylinder. Without the operational system, you may notice the additional exhaust smell while sitting at red lights.

Second, without positive pressure in the system, hot exhaust gas is going to travel up the injection manifolds and quickly damage the check valves. From there is will burn the hoses, damage the diverter valve and leak exhaust fumes through the gutted pump under the hood.

[Joe L.]

Re: AIR Pump

Two things. First you are not going to see any performance gains from removing the vanes from the pump. The system works with exhaust gas which has already passed through the power cycle in the engine. It simply adds a little bit of oxygen to the hot exhaust to aid in combustion of fuel that did not burn in the cylinder. Without the operational system, you may notice the additional exhaust smell while sitting at red lights.

Second, without positive pressure in the system, hot exhaust gas is going to travel up the injection manifolds and quickly damage the check valves. From there is will burn the hoses, damage the diverter valve and leak exhaust fumes through the gutted pump under the hood.

Michael------


I agree with both of your points. I do not recommend the disablement of AIR systems, either by gutting the pump or any other method. Especially with a convertible, one WILL experience more noxious exhaust fumes that partially spoil the driving experience. As cars have gotten cleaner-and-cleaner most folks have become used to a "no fumes" driving experience. Consequently, we are much more likely to notice it when fumes are present. Older cars are "fumy" enough as it is, so why make it any worse by eliminating AIR?

[Terry M.]

Re: AIR Pump

Terry-----

The overhaul procedure is covered in the 1967 edition of the factory overhaul manual. I don't know if it's covered in the 1968 manual. The C2 AIR pump is somewhat different than the C3 pump but the basics for overhaul are the same for both.

There is no Overhaul procedures for the AIR pump (section 6T) in the 1968, 1969, 1970, or 1971 Chevrolet Overhaul Manuals. After searching those four books I gave up. I do have other Passenger car and truck Overhaul Manuals, but the library is closed.

[Grant W.]

Re: AIR Pump

Hi William
the easist way to take the bake lite vains out is:
1. Take off the plastic fan in front, don't break it if it is the white opac one. repops are not the same
2. press out the small round spacer( one that the smog pulley is bolted to)
3. At this point the rear backing is taken off carefully, then you press out the main barrel
once the barrel is out then you take out the rear bearing as in Lawrence's picture.
Then all the inside guts will come out.
If you can't take out the front round spacer in front then the only way is to take a long plyer and a chisel and break up the vains. Eventually all broken pieces will come out.
I have taken many apart but if you really don't have the tools then just leave it as is. or if you really want it out just pm me and maybe we can figure out something.
Thanks, Grant

[William P.]

Re: AIR Pump

Thanks for all the reply's. The main reason that I want to remove the vaines is popping out of the exhaust when shifting gears . I rebuilt the engine to origonal specs ( 71 LT1 ) and added the AIR system which was missing . There didn't seem to be the exhaust popping before adding the AIR .

Regards Bill

[Jim T.]

Re: AIR Pump

Having a 68 with AIR, from my experience the popping in the exhaust could be attributed to something else. A ruptured power valve in your Holley provides a richer air/fuel mixture and provides the condition for the fresh air supplied by the AIR to burn the richer exhaust after it leaves the cylinder head. Start your LT-1 and put a finger over the front vertical vent for the fuel bowl. If your LT-1 dies in a few seconds the power valve is ruptured. There is a different test of the power valve given on Holley's web page.

[Joe L.]

Re: AIR Pump

Thanks for all the reply's. The main reason that I want to remove the vaines is popping out of the exhaust when shifting gears . I rebuilt the engine to origonal specs ( 71 LT1 ) and added the AIR system which was missing . There didn't seem to be the exhaust popping before adding the AIR .

Regards Bill

Bill-----


Another possible culprit that can cause this condition is a failed diverter valve. A check can be performed by removing the valve from the car and observing the internal activating shaft through the outlet port. Apply vacuum to the vacuum port with a Mityvac or otherwise and you should see the shaft move. If it does not move, the valve is defective. Unfortunately, if it does move the valve can still be defective in other, non-observable ways. Bill Hodel can rebuild it for you.

[John H.]

Re: AIR Pump

Bill -

"Popping" in the exhaust on over-run is almost a guarantee of a failed diverter valve diaphragm; it's also a significant vacuum leak - cap the port the diverter valve signal hose is connected to or stick a BB in the hose - that'll take care of the vacuum leak.