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Advance Auto Parts, is now the largest retailer of automotive replacement parts and accessories in the United States by store count after acquiring CARQUEST in October 2013.

(I like this store - you should check this store often since they have good sales! ~ Editor)







I had tried to scan some pages from my service manual, but the inside edge did not come out real well. I also took some pictures of the pages, so you can get some info from it. The one item that is a scanned jpg, actually has 4 pictures to it, not the top pictures that you see.

Tubular! The California Scene is always popular! So why wouldn't you want to relive those scenic highway, surfin' safari days of yore with your period correct SoCal cruiser? Of course you would! Forget those bush league Guide T-3 headlights ... what could be more cool than to top off a complete restoration with a correct -- and functional! -- A.I.R. (Air Injection Reactor (smog)) system for a 292? You bet! Otherwise, you're just ...

California Dreamin' ... Get some A.I.R. !!!
By Randy "SD66Burb" Solle
1966 Suburban
Bolter # 19386

This Tech Tip covers hoses and belts for first year
(1966) smog system on a 292 engine.

June 21, 2016

Secondary Air Injection System Restoration
Not hard, you just gotta find (or fabricate) the parts!

Smog pump or pollution pump is a secondary air injection system used as a vehicle emissions control strategy which was introduced in 1966. With this system, fresh air is injected into the exhaust stream to allow for a fuller combustion of exhaust gases. As car manufacturers began to replace carburetors with electronic fuel injection, air injection systems were no longer necessary as the amount of unburned fuel in the exhaust was dramatically reduced. -- Wikipedia has more, if you want to read it.

In 1966, California required that vehicles begin to use a smog pump system, or Air Injection Reactor (A.I.R.). Unfortunately, there is little listed or shown regarding this system as far as components are concerned.

My vehicle is a 1966 Chevrolet Suburban with the 292 In-line 6. The smog system, as far as I know, was for 1966 only. It seems most other 292s with A.I.R. found a trash can along the way. That was one reason I wanted to leave it on.

Like the others, I had the choice of removing the entire system, or try to find and replace what was faulty. I decided to keep it, since I am restoring the 'Burb to its original condition anyway.

The 1966 Service manual has a section pertaining to the smog pump itself and mixture valve, but that's about it. On our's, the pump and valve seemed to be working alright, so my main concern was the air intake manifold, hoses, belts, air cleaner, and how it all connected.

<<< click on the image for a larger view >>>

The image on the left shows the air manifold (gold colored pipe) with drops going into each cylinder of the head (not the exhaust manifold, as normally seen), with the check valve, and the hose going into the check valve.

My air intake manifold (the metal tube that has drops into each of the cylinders) had some issues. Where the drops connected to the main tube, the three rear tubes had eaten thru from the hot gasses. I made new drops out of fuel line, brazed them while connected to the head, and had it replated.

Now came the tough part -- trying to find hoses to fit everything!

The original hoses were special in order to handle the hot air being run thru them. Neither GM, nor any of the local auto parts stores, have any record for them. I just tried to locate pre-formed heater hoses and hope they would hold up for awhile. It's not like these vehicles are going to get 100,000 miles put on them again.

So, you have four main components that need to be connected:

  • air cleaner
  • pump
  • ai r manifold
  • air mixture valve

The air cleaner in itself is not a standard 1966 model item for the 292. While trying to find a filter for it, I discovered it was an air cleaner from a 250 that someone had modified, and added another hose connection to it.


<<< click on the image for a larger view >>>

You can see in this picture, that the right hand air bung seems to be an after thought.

The back bung is a breather line that  uses a 1" ID hose, from it to the hole in the side of the valve cover.

For this, I just used a standard piece of straight heater hose.


<<< click on the image for a larger view >>>


On this image on the right -- talk about spaghetti! I still needed to get a fuel and vacuum line in this mess.

The open line pictured on the lower right of the carburetor is the vacuum line for the brake booster. The yellow on the exhaust manifold is tape to keep out the local inhabitants.

For the remainder of the hoses, the local parts store allowed me to go rummage thru their hose racks to see if I could find something pre-formed that would work, and here is what I have come up with. If you try to use a straight piece of hose and bend it around, they just kink and do not look appropriate.


<<< click on the image for a larger view >>>

Grommet hole in side of valve cover goes to passenger side bung in air cleaner, and large hose in center of picture goes to drivers side bung in air cleaner.

For the hose that goes from the air manifold to the pump, which is the top one in the picture, I used a piece of hose "Car Quest #19657." This was a longer hose that I cut a section from that seemed to fit.

The next hose down in the picture is from the air cleaner to the pump, which was "Car Quest #E71986. This also was a longer hose that I cut a section out of.

The next horizontal hose from the mixture valve to the pump was "Car Quest #80412." This hose needs to be 3/4" ID on the pump, and 1" ID on the valve, but the hose was 3/4".

I put an oversized socket in the end to stretch it out on the valve end and was able to get it on without much effort.

The last hose on the right was the one that was on it from before and seemed to be all right, so I have no information for it.

In regard to the fan belts, the one closest to the block is Gates #9400, and the outer belt closest to the radiator is Gates #9510.

The air cleaner element was "Car Quest #87088."

Here are some more views that may be helpful

I doubt there are many of these systems left in use, but hopefully this may save the next person some time rummaging thru dusty hose racks.



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The secret of getting started is breaking down your complex, overwhelming tasks
into small manageable tasks and then starting on the first one.

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