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Super 6 Header, emission and distributor advance questions
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Author:  Scott H [ Mon Feb 16, 2009 9:07 pm ]
Post subject:  Super 6 Header, emission and distributor advance questions
I had a great day showing my son and his friend the basics of hot rodding techniques. (bigger carb and free flowing exhaust) I am working with a stock 1 bbl 1980 Volare with only 60k original miles . The car was running pretty well. Once I got into tearing it apart I saw that there were cracked brittle vacuum lines all over and the throttle shaft is very worn. I pulled the factory exhaust and found the cat was rotted from the inside and so was the muffler Im going it add a new high flow cat to the exhaust after the header collector. I removed the air pump but this block had a 3/4 inch hole after the rear most exhaust port that had a metal line with a check valve running to the air pump. Since the air pump is gone can I just block this off with a metal plate?
The Super Six intake I got has an EGR setup. I leaned today that all you have to do is turn the EGR upside down and this will block off the open hole and seal it up. If I do end up running water to the base of the intake to heat the carb this setup will prevent water from entering the intake.
Next the air cleaner has a vacuum operated valve / solonid on it that seems to sense the air temp at the air cleaner. The vacuum lines go from the dist to this valve. Can I eliminate this valve on the air cleaner and just run the dist vac from a ported carb line?
Finally there is a ho toward the back of the engine. My guess is that this controlled some of the emissions equipment (EGR, Vac pump, Dist Vac control that has been eliminated when installing the headers, can i remove this stuff too and just hook up the evap canister and connect the vac line direct to the dist? Pics are below.
Thanks,
Scott

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Author:  coconuteater64 [ Tue Feb 17, 2009 3:52 am ]
Post subject: 
The hole in the head is for the Air Injection Reaction system. When you remove the A.I.R. pump, you can safely block it off with a plate as you describe. I went to the hardware store and and found a copper end cap in the plumbing section, and just "bonked" it in there. I did the same thing to the EGR hole in the manifold. Of course, as you say you could just flip the EGR valve and close it off. Guess I got carried away.

Not sure what you mean by getting water into the intake wit ha heated base though. :shrug:
Author:  dakight [ Tue Feb 17, 2009 3:59 am ]
Post subject: 
If you are going to replace the catalytic converter you will need the air injection pump to be present and operational.
Author:  Scott H [ Tue Feb 17, 2009 7:04 am ]
Post subject: 
Thanks, I did not think of using a copper end cap like you suggested.

I am going to replace the cat but with something that is a high flow, 49 state legal, and uses a modern ceramic design so the air pump will not be necessary.

Scott
Author:  SlantSixDan [ Tue Feb 17, 2009 7:49 am ]
Post subject: 
Quote:
I am going to replace the cat but with something that is a high flow, 49 state legal, and uses a modern ceramic design so the air pump will not be necessary.


That's not correct - you will definitely need to keep the air pump. There is nothing such as a "modern ceramic design" that differentiates the catalysts available now from the one that was installed at the factory - the only jokers who futzed around with pelletised converters were GM. Carburetors and catalysts don't get along well under the best of circumstances; if you install a catalyst and delete the air pump, the catalyst will overheat and melt down in short order. It is best if you can keep the air switching system in operation so the air is injected at the cylinder head location until the engine warms up, then is injected directly into the catalytic converter. If you can't, because the air switching valve is missing or defective and can't be replaced, then you'll want the air injected at the converter full time.

When selecting a converter, don't be lured by "high flow" advertisements — leave that silliness to the dumb kidzz with Honda Civiczzz who think they're gonna be the next Mario Andretti if they can just get enough flow (noise) in their car's exhaust system. :roll: There's not going to be a problem with flow; the bigger problem is getting a catalytic converter with sufficient catalyst loading to handle the very dirty exhaust (relative to modern EFI engines) that you're going to be putting thru it. It'd be a pointless shame to put the money, time, and effort into installing a catalyst that becomes nearly worthless in 9 months or a year, eh? The "high flow" catalysts generally have low conversion capacity and really aren't suitable for your carbureted application.

Fortunately for your flow goals, the heavy-duty catalytic converters with high catalyst load are sized, configured, and rated to handle the exhaust volume of big engines, and so they'll present virtually no flow restriction to your relatively small slant-6. A unit with 2¼" in and out, rated for engines of up to 470 CID (more than double the size and flow of a 225) and vehicles up to 7,000 pounds (way heavier than yours), in California (for the high catalyst loading), and with the tube connection for air injection.
Author:  Scott H [ Tue Feb 17, 2009 1:15 pm ]
Post subject: 
Thanks Dan,
Here is some more info, the air pump was not functioning, I replaced it and it failed with a week. My 80 does not have an air tube that goes to the Catalytic converter so I am pretty sure that a cat design withount the air tube will continue to be sufficient. The Exhaust pipe went from the manifold about 4-5 inches to a rectangular chamber. The air tube from the air pump went to this chamber not the Cat. The exhaust then snaked its way back to the catalytic converter which is under the passenger seat about 2 feet or so away from that chamber, about halfway to the mufflet, actually pretty far back for a converter.

Despite my message above I was sold more on the price $48 shipped and size 4" in diameter and 11" long than on any performance claim. I was looking at this one on ebay, looking again I am not sure what material it is, dont really care, just dont want to get jammed up in an inspection if it is missing (in NJ they do covert roadside inspections) this one is rated for up to a 5.9L so it think it meets the goals you stated.


Thanks again,
Scott
Author:  SlantSixDan [ Tue Feb 17, 2009 3:12 pm ]
Post subject: 
Quote:
Thanks Dan,
Here is some more info, the air pump was not functioning, I replaced it and it failed with a week.
Replace it again.
Quote:
My 80 does not have an air tube that goes to the Catalytic converter so I am pretty sure that a cat design withount the air tube will continue to be sufficient.
Run a cat with air tube and inject there permanently; block off the cylinder head injection location.
Quote:
The Exhaust pipe went from the manifold about 4-5 inches to a rectangular chamber.
Upstream catalytic converter. The three-way catalyst w/air tube I pointed to will replace this and the original underfloor converter.
Quote:
actually pretty far back for a converter.
Yup. Wrap the headpipe with Thermo-Tec wrap from the manifold flange back to the catalyst inlet to minimize raw fuel reaching the converter.
Quote:
Despite my message above I was sold more on the price $48 shipped and size 4" in diameter and 11" long
Not going to do much to clean up your exhaust...nor will it last very long for you.

(you've got a PM)
Author:  Scott H [ Wed Feb 18, 2009 6:16 am ]
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I might be missing something here. It was my understanding that the catalyst materials back then were not yet very good and the air pump was used to cool down the exhaust temps and to add o2 to help cut emissions. There are plenty of catalytic converters out there that do not utilize an air pump. In my particular case this car already passed emissions without the pump and with a non functioning cat that was basically gutted on the inside. This was even with many bad vacuum lines and a really worn throttle shaft on the 1bbl carb.
Anything I do will improve the way this one runs and proper tuning will reduce the emissions even further. I have no objectionto the pump per se but I dont see where there is anything to be gained by replacing it again.
I would be better off thring to retain the EGR by trying to cut the heat box off the old exhaust manifold and porting a tube up from the collector to get exhaust gas to the EGR but again the small advantage in milage does not yet justify the effort.

I am beginning to see why Dutra Duals are a great solution but I have embarked on the Header path and need to see it through.
Scott
Author:  SlantSixDan [ Wed Feb 18, 2009 6:41 am ]
Post subject: 
Quote:
I might be missing something here. It was my understanding that the catalyst materials back then were not yet very good
The catalyst substrate back then was the same as it is now in most cases: a monolithic honeycomb matrix made out of ceramic.
Quote:
and the air pump was used to cool down the exhaust
No. The exhaust needs to be as hot as possible for the catalyst to work efficiently. The air pump adds O2 to the exhaust stream. When it's injected upstream (@cylinder head), the O2 causes unburned fuel in the exhaust to ignite after it leaves the cylinder. This heats up the exhaust to get the catalyst up to temperature faster. When it's injected at the catalyst, it is to enable the catalytic reaction inside the converter.
Quote:
There are plenty of catalytic converters out there that do not utilize an air pump
Yes, mostly on fuel-injected cars with relatively (very) clean exhaust. The parameters of the whole installation (engine + fuel and engine management system + emission control system) determine what kind of air injection is needed, or none at all.
Quote:
In my particular case this car already passed emissions without the pump and with a non functioning cat that was basically gutted on the inside
Well, what's the point of the exercise here? To have your car emit exhaust that's as clean as possible for as long as possible? Or to pass the test?
Quote:
I am beginning to see why Dutra Duals are a great solution but I have embarked on the Header path and need to see it through
Oog, I forgot you're running headers. You're going to want to coat them (e.g. Jet-Hot) and/or wrap them (e.g. Thermo-Tec) or your catalytic converter will be basically useless until it melts down from the borderline-cold, raw-fuel-rich exhaust coming off the headers.
Author:  dakight [ Wed Feb 18, 2009 6:48 am ]
Post subject: 
The air pump was used to add oxygen to the exhaust stream so that the catalyst could burn the remaining unburned fuel and carbon monoxide. The addition of oxygen actually caused exhaust temps to increase rather than cooling them. Some form of air injection, not all used a pump, is essential for the catalyst to work correctly on a carbureted system. Modern fuel injected, computer controlled systems are able to control the mixture to the degree that added oxygen is not needed. However, it's your car, do as you please.
Author:  Rug_Trucker [ Wed Feb 18, 2009 7:05 am ]
Post subject: 
Do the newer "peanut" style heads have jets in the exhaust ports?

I will be doing some porting on a 77-78 California spec head from a van. It will be going into an '80 Federal spec van.
Author:  Scott H [ Wed Feb 18, 2009 7:47 am ]
Post subject: 
Thanks for all the input. This is certainly very informative, I am glad I asked the questions.
Scott
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