I'm looking to restore a smog pump cosmetically before I install it on my '69, but I think I'd like to disable it so it doesn't actually work.

I have an original white fan to add to it. Anything special in putting this on? Anyone have experience disabling a smog pump before installation?

Made a deal with a forum member on a set of smog parts that's not working out very well. Could use a step in the right direction here.

 

VB5869,

Try Bill Hodel, his # is 330-832-0871. He has everything you need to rebuild the AIR system and can probably answer any question(s) you have.

 

Steve, I considered modifying the A.I.R pump on my 70 LT-1 as you describe. After looking at the internal pump configuration, It didn't appear as easy as it might sound. In order to run the pulley with a belt under tension, the bearing /shaft assembly has to be maintained. The only thing left to deal with is the metal air impeller blades that actually pump the air. Removing them did not look to be easy, without considerable risk to the eccentric pump shaft / assembly. I guess you could cut them out, but why? I elected to leave the pump operational and put plugs in the individual air tubes down by the exhaust manifold. I did replace the front bearing and re-greased the aft bearing assembly. The front bearing is a sealed bearing and is permanently epoxied in the housing. If it is bad, be very careful pressing it out, because you run the risk of damaging the housing. I got lucky and it popped out without damage. Today's bearings have a sealing compound available to reliably secure a new bearing without having to rely on the old method that GM used with epoxy grooves. I took some pictures back when I was dealing with this. I will look for them tonight if you are interested.

Bullshark

P.S. Installing the white fan is pretty straight forward press the metal hub out of the old fan......it only comes out one direction so look at it close. It is groved on the circumference so it just press fits back into the new white plastic fan. The same metal hub is used for both the newer black fan and the older white one.

 

Thanks Bob, I'd be interested to see pics if you have them easily accessable.

A couple of people on another thread mentioned the easy way was to remove the rotor vanes, reducing the pump to just spin, acting as an idler pulley. Does this make sense to you?

 

yeh, I heard that too, I just didn't see an easy way to remove the vanes. Maybe I just missed it. I will see what pics I can dig up

Bullshark

 

If you do remove the vanes [to eliminate pumping action], you will need to block the pump outlet so that exhaust doesn't back-flow into the A.I.R. pump.

 

If your new fan is on a hub I would pull the old one off with a puller. I made one and used the threaded holes. To remove the vains you need to pull the top off the metal cylinder. I just made up a puller to do this also. You must pull the hub and fan to press the shaft out of the bearing with the back unbolted off. Not too bad of a job if you have a press.

 

You can leave the pump intact and let it pump out into the atmosphere and it will not cost a bunch of HP and still can function as a pump later if you need it to actualy work. I just punch a lot of holes in the underside of the rubber hoses where they will not show to releave the pressure and put pan head screws inside the trees to block the exhaust flow from backing up into the system. Remove the stainless steel pipes from inside the manifolds while you are at it. This is a functional, middle of the road solution that is easily and cheaply reversible. This will eliminate the effects of a poorly functioning diverter valve or a bad tune situation. Probably gives a few HP back but who knows.

The vanes inside the pump are very fragile and made of a carbon like material. They can be easily destroyed/removed with a screwdriver but then it will never pump again. Just acts like an idler pulley this way. Not real pretty but it will eliminate the minor HP loss. Not worth trashing the pump IMHO but it ain't my car.

-Mark.

 

Here are some pictures I took awhile back when I rebuilt my smog pump.



I pressed the front bearing out. Here you can see the epoxy grooves I was talking about on the old bearing.



The vanes are captured inside the cylinder. I didn't see an easy way to remove them without damage. As stated above, I guess the rear bearing plate/ cover could be pulled out, but I didn't see how at the time.



The hub is easily pressed out of the plastic fan and then pressed back onto the white fan.





Bullshark

 

Nice pic's
I used two bolts in the holes to pull the end out of the cylinder. The hard part was keeping a piece of square stock on the small outer edge of the cylinder on both sides with a flat bar on the top with two holes in line with the ones in the end. It pulled easy.

 

Nice pics Bob, thanks for the help.

 

there are check valves in the A.I.R system that prevent engine exhaust from getting to the pump...

 

The check valves are threaded on the end of the manifold tubes and the rubber hose clamps to them. You are saying they should be plugged?

 

A 3/8 pipe plug fits in the hose perfect to block it off right after the check valve and under the clamp. The downside is the tubes will get too hot and burn out. It is best to plug each tube at the manifold. The check valves fail fast in a system not working.

 

Well after looking over this thread, it seems maybe it's a better choice to leave the pump operational and not crack the back open. Doesn't seem worth it to junk the part.

Bob, your statement above seems to say all you did was plug off the tubes at the manifolds. Is that all? You let the pump run?

The fan came today and it's mounted on tha hub. I suppose a pull and swap shouldn't be too awful. I'd love to find a way to get the casing clean like Ive seen in the pictures of a few pumps on here. Some by Hodel, others cleaned by people. They say they just used "elbow grease" but they look sprayed cast silver to me. I scrub with steel wool and its getting there, but is uneven and sometimes seems too shiny. Is there an aluminum wash or cleaner that will just clean these things nicely with the case intact? I've been unsuccessful with lacquer thinners, brake cleaner, stripper, and others.

 

Scrub with Simple Green then follow up with some aluminum mag wheel cleaner designed for bare rough cast wheels. Try not to let any moisture get into the pump. If that isn't good enough I would consider sending it out to a pro.

-Mark.

 

Walnut shucks and low air pressure may be the finish your looking for. It's best to try a test on some junk part to see if it has the look you want. Make a puller for the fan becauce you can break the new plastic fan.

 

Steve, To be honest, I haven't actually plugged off the tubes yet. I have two coin shaped plugs, that I plan to insert between the tube assy and the check valves. I was thinking that would be all that is needed since the the job of the diverter valve is to regulate the air flow. After reading some of the posts in this thread, it might be worth while looking into an additional approach to taking the load off that expensive valve and plugging its vacuum source???
I have also heard of people using individual flat head type rivets to plug each of the tubes down by the exhaust manifold. Not sure if that would be any better, since the tubes will get pretty hot anyway??

Bullshark

BTW, I don't think you need to make a hub puller for the old fan, I used a standard three point small puller available at any tool store?? The new fan was just pressed or tapped back on the shaft. Take note of the original position of the fan.

Also, depending on your driving habits, it just might be easier to leave the whole system operational. I have thought of that for the LT-1. It doesn't sap much power at all and you NCRS guys aren't going racing anyway.....Right?

 

You don't need a special puller unless you want to save the plastic fan and hub as a unit.

 

Interesting you should say this... an hour or so ago I had this same conversation with the guy who will be taking out my motor... he sees no real reason to disable it.

Problem solved. Maybe I can iron out the cosmetics this weekend.

Thanks for the tons of help, contributors.