Exhaust Heat Riser....and resurrection of the Rev

[Mike Andresen (27410)]

I just got back from a week's business trip to find that over 900 messages had been posted on the NDB in my absence. You boys have been busy!

Reading the runaway thread from Friday on the Exhaust Heat Riser got me thinking. I have a 66 w/original 300 hp AIR motor, original intake and exhaust manifolds, replacement Holley carb. Also the belt to the AIR pump has been removed so it is not functioning (the pump is seized). At start up I get a lot of exhaust flow out the right side (I think) and it takes an inordinate amount of time (5 to 10 minutes) to warm up and idle steady.

First question is, does my car have this exhaust heat riser? Pardon my ignorance on this.

Second, do these symptoms sound like those of a butterfly valve stuck open?

Third question, what if any operational or wear concerns should I have by running without the smog pump operating?

Fourth question, is the Reverend Varoom going to respond to the trashing he took in Friday's thread?

Thanks for the entertainment!

Cheers, Mike

[Bill Clupper]

Re: Exhaust Heat Riser....and resurrection of the

Yes, your car should have an exhaust heat riser. The exhaust flowing out of one bank only at startup is evidence of this. I haven't studied the typical warmup time on these, but when the engine is cold, you should be able to gtab the counterweight, on the pass side just below the exhaust manifold outlet and see if it moves freely. It is not attached to the smog system in any way on these early smoggers.

[Wayne M.]

Re: Exhaust Heat Riser....and resurrection of the

Mike --- As the heat riser is on the right (pass) side, if it is functioning (closing cold) you should notice more exhaust gases out the LEFT pipe, becoming more equal as the butterfly opens on the riser.

[Joe L.]

Re: Exhaust Heat Riser....and resurrection of the

Mike-----

As far as the A.I.R. pump and system goes, you will not harm the car in any way by leaving the system inoperational. In fact, these systems were commonly removed from cars and, for 1966 cars, removal of the system has the least effect of any. That's because for 1966, the system was mostly just an "add on" and not fully integrated into the overall fuel/ignition system. A specific carburetor was used, however, for cars with A.I.R.

If it were me, though, I'd get the pump rebuilt and back "on line". For a short while the pump on my 69 was out of service when the replacement pump that I had on the car siezed up. I noticed a marked increase in "exhaust fumes" during this period, especially during top down driving. So, this system has some real benefits for the OCCUPANTS of the car, as well as others that have to breathe the air. You can be sure that when my "ZL-1" project is complete and installed, it WILL HAVE a fully functional A.I.R. system.

In any event, just be sure that you don't throw that 66 A.I.R. system away (like a lot of now-sorry folks did). The 66-67 A.I.R. systems are scarce and valuable and only the manifold tubes are reproduced. A complete, used system generally fetches $1,000+.

[Mike Andresen (27410)]

Re: Exhaust Heat Riser....and resurrection of the

Thanks to all for the advice. Joe, I definitely won't be throwing the AIR system away. All pieces are there except it appears to have a replacement pump which has seized. Are they difficult to rebuild? Any advice on where ot get the correct pump? It seems when I've looked before they are also quite expensive.

Cheers, Mike

[Joe L.]

Re: Exhaust Heat Riser....and resurrection of the

Mike-----

How do you know that it's an incorrect pump? The 66-67 pumps were quite unique and Corvette-specific so I don't see how you could have a non-original type pump if it's as originally installed. Even though the pump has siezed, it can likely be rebuilt. Send it off to Bill Hodel who advertises in the Driveline.

Due to the fact that these pumps are Corvette-specific, they are very difficult to find. 66-67 passenger cars used the same basic pump, but the tube configuration was different. Also, 66 and 67 Corvette pumps are different.

[Mike Andresen (27410)]

Re: Exhaust Heat Riser....and resurrection of the

Joe, You certainly got me thinking on this one. The reason I think it's not correct is that it looks different than what is shown in the AIM and in the service manual. The main difference is that there is no hose from the air cleaner to the pump. In fact I do not have the tube on the bottom of the air cleaner which I believe should be there on an AIR car. Instead the pump appears to take it's air straight from the engine compartment although I'm still baffled as to where it's air intake is. This is when I wish I had a digital camera! The airpipes into the exhaust manifold and diverter valves are all there and it's all plumbed in. It even had the belt on it for over a year after I bought it but I removed it when I failed a water pump and found that it wouldn't turn.

To get to the bottom of things, here are the numbers off of the back of the pump:

7832904 (maybe 7832804, the ole eyes have started to fade quickly after 40!) O45 A8

Can you make anything out of this? Is it original or do I have a passenger car arrangement for the pump or is it something else altogether? Perhaps it's possible that the pump is correct but I just have the wrong tube combination (I hope never to hear that complaint from the wife!). Please let me know if you can decipher something from those numbers or if there is somewhere else I need to look.

Thanks for the advice Joe.

Cheers, Mike

[Mike Andresen (27410)]

Just one more thing......

Joe, Just to make the story complete here are some of the other numbers you might wonder about.....

Block Pad Stamp - 6122652 F0517 HH Exhaust Manifold Casting # 3872765 Left

3872778 Right

The last 6 digits on the pad match the VIN so all appears correct. The HH and the exhaust manifold casting #'s pretty well confirm that this is an original AIR car. I bought it from the original owner in Laguna Beach, complete with the POP and registration info showing he originally bought 6/6/66, 22 years after D-Day, so I guess it just had a birthday.

Probably more info than you need or wanted to know but thought I should be complete.

I look forward to hearing back from you.

Cheers, Mike

[Robert C.]

Re: 6/6/66

Geeeez, 666, What was the original owners NAME ????????????


Texas Chapter NCRS

[Joe L.]

Re: Just one more thing......

Mike-----

The air inlet for the 66-67 AIR system was located on the rear of the pump and was a tube with a ridged end that was a press fit into the pump backing plate. There was another tube connected to the air cleaner base which had a 90 degree bend and faced forward. Then, a short length of rubber hose connected the tube from the A/C to the AIR pump with hose clamps securing each end.

The outlet from the pump was from a "T" fitting which was a press fit into the body of the pump and was located at the bottom of the pump as oriented when mounted on the engine. Rubber hoses connected each end of the "T" to the manifold tube assemblies on either side of the engine.

Although the 66 and 67 K-19 systems were a bit different and used different AIR pumps, the configuration of the pumps was very similar and as described above. If your pump is configured like I described, then you have a Corvette pump, whether it be a 66 or 67. Other cars used similar pumps but different inlet and outlet tubing configurations. I cannot tell which pump you have from the backing plate casting number which you provided. These backing plates were never a SERVICE part and were often common among many different pumps.

If your car has the fitting on the back of the pump which is NOT connected to the tube at the base of the A/C because there IS NO TUBE at the base of the A/C, then I'd say that you have an incorrect A/C base. That's not a surprise since the 66-67 K-19 A/C bases are hard to find. If your car lost its original A/C somewhere along the way, the chances are that a non-K-19 A/C was used as a replacement. This leaves the AIR pump inlet fitting with nowhere to connect, so it just gulps unfiltered air from the engine compartment.

[Mark J.]

Let's compare cars

Mike,

You mentioned that you bought your car in Laguna Beach. I have a '66 with an original smog pump and I live in Laguna Niguel. Are you nearby? If you want, we can meet one day and compare notes. I just had my pump remanufactured by a sub of Baum's Auto Supply in Mission Viejo. Nice job, I might add.

Mark

[Mike Andresen (27410)]

Long Way To Laguna Niguel

Mark, Thanks for the offer and I wish I was still there. Since I bought the car we've been transferred twice. First time to Peoria IL and the next time to Belfast, Northern Ireland. Talk about bad luck!!! If I were still there I'd plan a rendezvous at Pamona. I remember many an early Sunday morning there, toasting sunrise and enjoying the smells of pre smog control California! Alas I'm stuck here in the wet and cold. At least the Guiness is good.

Cheers Mike

[Mike Andresen (27410)]

Re: Exhaust Heat Riser....and resurrection of the

Joe, Your description is what I've seen in the AIM but not in the iron. I would like to see something to confirm what I've got. I was disappointed that the numbers didn't mean anything. Bummer.

The AC base has a rubber plug where it looks like a pressed in tube could go for the air inlet. It's at the 3 o'clock position on the base (ie. right side)

The pump itself has a 90 degree fitting coming off of the upper right rear of the pump and pointing to the away from the engine (ie towards the right fender). From this fitting, pointing towards the firewall, is a different L type fitting into which the two hoses from the manifolds mount to. From this same fitting, pointing towards the radiator is what looks like it could be the air intake. There are several small holes around it with a foam type material inside, my guess it's some sort of filter but it doesn't look easily serviceable. There is a vacuum line from the carb which also goes into this fitting. Frankly it all looks pretty bizarre.

Bottom line is that it doesn't look anything like what you've described or what I've seen in the AIM. So it looks like I'll be scouring the swap meets for the correct pump once I return to the good ole USofA. I'll also contact this Bill Hodel. A friend of mine with a beautiful 1971 LT1 has recommended him as well.

As always Joe thanks for the advice. If my description helps at all I'd appreciate your thoughts on what kind of contraption I might have. My guess is that when the engine was overhauled by the original owner 10 years ago, the shop that worked on it put on some goofy replacement unit rather than overhaul the original. Can't do much about that at this point, just belly up to the bar sometime in the near future to do it right.

Cheers, Mike

[Mark J.]

Air Injection Reactor System

Mike,

Sorry, I don't think I can make it to Northern Ireland before lunch . However, if you have access to the "Vette Vues Fact Book", by M.F.Dobbins, there are several pictures of the A.I.R. system on a '67 with the proper hose placement. I know the '67 pump is slightly different from the '66, but the hose placements are the same.

We are having a heat wave today, so have a Guiness for me.

Mark

[Mike Andresen (27410)]

Re: Air Injection Reactor System

Mark, We had a heat wave here too. It hit nearly 65 degrees! Have a margarita for me and I'll raise a Guiness to you.

I'll also add another book to the Christmas list. That's one I don't have yet. Just bought Antonick's Illustrated Buyers Guide last week which is a good read.

Cheers, Mike