I took my brother's 83 Dodge van in to get emissioned today. I have been refurbishing it for him for the past three months to get it back in driving condition after being in outdoor storage for five years.

One of the problems with the van was that it barely passed emissions. The motor was a 1976 225 rebuilt to 76 specs. He had a Holley 1945 on it and a previous owner had removed the lean burn computer and carb and all emissions stuff. I swapped it to a Super Six and replaced the hollowed out original catalytic converter with a universal replacement converter from Summit. I also added an AIR pump and the new catalytic also has air injection.

It passed 1983 emissions with flying colors! The van is supposed to be a lean burn one barrel but a non-computerized two barrel passed great with a recurved distributor and only a catalytic and air injection. I think the catalytic is what did the trick.

Yay!

Yes, a good cat and air injection to burn any excess fuel will clean up some dirty pigs. Rotary engines are a good example. You just can't burn too much fuel for very long and have the cat survive. If the carb is in good shape and calibrated well it shouldn't be a problem. Glad to hear the project is working out well for you.

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Joshua

I used to do that to get my old Mazda RX2 to pass tests (when it had to pass tests).... I added a cat for the test and rerouted the airpump bypass to the cat....... Take off and reinstall normal exhaust after test.....

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

But you need an air pump, right? Does an air injected catalyzer do a big thing on carbon monoxide (my main problem)?

Yes, I needed an air pump only because I wanted to use a three way catalytic with direct air injection. Summit also sells two way converters without air injection so you can run just the converter but no air pump. Slantsixdan posted a good description of different types of catalytic converters and what they do and how they work. Do a search and you will find it.

FYI here are the test results for my brother's van:

HydroCarbons (parts per million)

CRUISE: Limit = 150, emissions = 90 (richer than I would like, but it still passed)
IDLE: Limit= 220, emissions = 45

Carbon Monoxide (%)

CRUISE: Limit = 1%, emissions = .23%
IDLE: Limit= 1.2%, emissions = 0%

Carbon Monoxide + Carbon Dioxide (%) (This category you must be above the limit to pass)

CRUISE: Limit= 6%, Emissions = 13.93%
IDLE: Limit= 6%, emissions = 10.9%

Strangely, Washington has stopped testing for NOX, and at leaSt in Pierce COunty where I live there is only a gas cap and sniffer test--no visual.

So there you have it. It is possible to build a stock non-smog motor and hang a catalytic on it to pass emissions. THis is with a stock cam and carb though, so I don't know how much performance parts would affect it.

Thanks

I'm impressed; you did a fine job.

The virtual of the feedback systems is to compensate for leaks, wear, etc. over time. I'm interested in hearing how well it hold up over time and with changing fuels.

Our areas recent mandated change to gasohol seems to have a noticeable effect in my carburated cars. I'm thinking about having to adjust and/or rejet the carb. I've also noticed that the gasohol seems to be reacting with copper and tarnishing it.

Could you explain the CO+CO2 test? Would a car that only exhausted pure air fail?

No, the feedback system's purpose is to keep the air/fuel mixture within a certain narrow range to permit both the oxidation and reduction catalysts to do their job. This narrow control cannot be achieved without feedback.
Yep, all of that and more. Poorer mileage, accelerated and increased degradation of fuel system materials, worse power, and—surprise—usually only lower emissions in poorly-maintained, old vehicles. Thank your local farm lobbyist.
It validates the other parts of the emisison test, and looks at O2 plus CO2, not CO + CO2. If O2 is too high relative to CO2, it indicates exhaust dilution (as for example by an air injection system that isn't working right, or has been deliberately jiggered to dilute the exhaust and try to fool the test).

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks! If its worth doing, its worth doing well.
We'll see. The van is back in my brother's hands now so only time will tell how well he maintains the motor. I probably won't hear anything about it until it fails again.
My understanding is that gasohol is a mix of ethanol and gasoline. Ethanol is much more corrosive than gasoline so you may have to replace the rubber fuel lines on your vehicle as well as get some sort of protection for the metal bits. I know there is info on the web about the steps necessary to make your car run on pure ethanol, so you should be able to find out what you need to do to protect your copper parts.

Rejetting may be necessary due to the lower energy potential of the ethanol in the mix. Typically cars that convert to all or part ethanol fuel have to increase jet size. However, you may also be able to increase timing advance and compression.
Not really. I am not sure why that test is the way it is, and I am also not sure why the State doesn't test for NOX anymore. All I know is that they do it that way and the van passed! Honestly, I have never had a vehicle fail emissions except for my Ford van before I rebuilt the motor and reinstalled an AIR pump for the catalytic. Now it passes great. The best thing you can do is keep your motor in a good state of tune.