Catalytic Converter on a 65 Slant 6?

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schmoe

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This may sounds crazy to many... I am trying to figure of ways to have my daily driver 65 Dart GT not smell terrible.

Has anyone added a Catalytic Converter to your pre-smog Slant 6?

Or does anyone have any recommendations on how to make it burn cleaner? I have electronic ignition, new exhaust, it is tuned up really well, has no mechanical engine problems - it just smells like a old lawnmower when I am sitting in traffic.
 
have you tried fabreeze ? :)

But seriously, try using a different oil. Maybe a 20w50 synthetic blend, I would not put a cat on it.

And fix any oil leaks you have.
 
I'm no expert in this area, but I have smelled pretty bad smells from Cat equipped vehicles as well. It sounds like you have everything in order.Could it possibly be oil seepage on from the valve cover to exhaust manifold? It wouldn't take much. How about a rich idle circuit?
 
Yes, I have reservations of putting a CAT on it too.

I have adjusted between very lean, too rich, everywhere in between. Spark plugs are clean, dry with no deposits.

Oil leaks are under control. It is a smell from the exhaust pipe not a dripping leak.

Does synthetic make a difference on this? I had not thought to try that. Right now, I am running 30w with 1 quart of Lucas.
 
Hmm, I use straight weight 30 in my lawnmowers. Maybe there is something to that.
 
Adding a cat is not that bad of an idea. It will greatly reduce NOx (oxides of nitrogen) which definately has a stink to it. Air injecton makes them even better, but not really necessary if you install it close to the manifold, and keep the tune up spot on. Some type of shielding from the floor is a good thing. Modern cats will have a very negligible effect on horsepower if any. Some pretty darn fast, quick, and clean cars have them.
 
well what is teh stick u speak of? not used to the smell of a little rich mixture??
 
I can't remeber the name of it but some years back I saw a product which when put in your gas tank gave off a pleasing odor from the exhaust.
 
Sometimes,the exhaust fumes can creep into your car,like from small holes in the firewall,or they can creep into your trunk and make there way into the cabin.Every old car Ive had,even when I rode in my parents old cars when I was a kid had that old car gas smell.I guess im just use to it,lol.:dontknow:
 
schmoe said:
Yes, I have reservations of putting a CAT on it too.

I have adjusted between very lean, too rich, everywhere in between. Spark plugs are clean, dry with no deposits.

Oil leaks are under control. It is a smell from the exhaust pipe not a dripping leak.

Does synthetic make a difference on this? I had not thought to try that. Right now, I am running 30w with 1 quart of Lucas.
Click to expand...

Your running 30W oil...a monograde.....why???
Better off using 20W50 or 25W60 ( summer )...and in winter 15W50 or 10W50.....both would be semi-syn's.
 
if you do this i siggest you look at a 1975/76 era Dart/Valiant to see where the
factory located the cat. You will need to heat shield the floor to avoid burning the car up.


As i recall; 1974/75/76 era cars were catching on fire because at the
assembly line someone got lazy and didn't attach the under floor heat shields.
 
http://www.tceq.state.tx.us/implementation/air/mobilesource/vetech/catfire.html



Precautions To Take

The EPA regulations require that any emission control system used by vehicle manufacturers "shall not in its operation, function, or malfunction result in unsafe conditions endangering the motor vehicle, its occupants, or persons or property in close proximity to the vehicle."

The vehicle manufacturers are aware of the need to provide protection from possible hazards or discomfort associated with high catalyst temperatures for both the vehicle occupants and vehicle components. In addition, protection is also necessary to avert possible fire hazards associated with driving vehicles through tall grass or other vegetation. The exact means taken by the different manufacturers to provide high temperature protection vary, and include such approaches as insulating the entire catalytic reactor so that the outside surfaces are not hotter than mufflers, installing protective metal shields between the converter shell and vegetation, and using thicker carpeting materials inside the car to protect the occupants from experiencing high floorboard temperatures. In addition, some cars have temperature-sensing devices to deactivate the catalytic reactor or alert the driver to abnormally high temperatures, which might be caused by misfiring spark plugs, etc.

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Fires May Still Happen

The EPA has received reports of vehicle and vegetation fires in which catalysts were involved from both vehicle owners and from the National Highway Traffic Safety Administration (NHTSA), an organization which has been monitoring the frequency of such incidents with individual manufacturers. In some cases, it appears that combustible undercoating material had been applied to the catalyst and other exhaust system hardware.

In most cases, vehicles were also reported to have been running badly with evidence of nonfiring spark plugs or other ignition system defects. If an abnormal amount of unburned fuel is fed to any catalyst, which occurs when the engine is misfiring in one or more cylinders, the catalyst will attempt to "do its job" by burning this fuel instead of simply expelling it out the exhaust pipe as the case with older cars. When this happens, the surface temperature of the catalyst container and the exhaust pipe can become abnormally hot, possibly leading to charring or burning of undercoating inadvertently sprayed on the catalyst or exhaust system, charring of floor mats in the car, or ignition of dry vegetation if the vehicle is operated off-road. Vehicle service manuals caution against applying undercoating on the catalyst of exhaust systems.
 
Nothing wrong with single weight HD oils. Not one single thing. As long as you run one with the zinc content or run a zinc additive, you'll be fine. That's the type of oils they ran when they were new and they lasted hundreds of thousands of miles. Modern oils are even better. Multi viscosity oils can only be one weight at the time anyway. A good 30 weight for warm climates and a good 40 weight for cold climates will do just fine. The most important thing is to keep the crankcase full with SOME kinda oil. I would advise against the cat, BTW. Cats are designed for engines running MUCH leaner than these older models.The extra unburned fuel in the exhaust can cause the cat to literally melt itself and burn itself up and possibly cause something close by to catch on fire as well.
 
Get yourself or find someone who has an exhaust gas analyzer and set you fuel mixture with it.
 
StrokerScamp said:
Nothing wrong with single weight HD oils. Not one single thing. As long as you run one with the zinc content or run a zinc additive, you'll be fine. That's the type of oils they ran when they were new and they lasted hundreds of thousands of miles. Modern oils are even better. Multi viscosity oils can only be one weight at the time anyway. A good 30 weight for warm climates and a good 40 weight for cold climates will do just fine. The most important thing is to keep the crankcase full with SOME kinda oil. I would advise against the cat, BTW. Cats are designed for engines running MUCH leaner than these older models.The extra unburned fuel in the exhaust can cause the cat to literally melt itself and burn itself up and possibly cause something close by to catch on fire as well.
Click to expand...

I was using Penrite HPR15 (15W60) engine oil, with Nulon E20 additive....the oil pressure guage would rise up quick on cranking....had 63psi.....never had a problem with it......that was in my 225 /6.
I will be using it in my 318/390 stroker when its done.
 
the only reason im putting a cat on my dart is so i can pass smog... then it comes back off...
 
Why not get the car dyno tuned using a chassis dyno. I had my car dyno tuned and they measured the exhaust gases and air fuel mixture. By doing this you will enable the engine to run properly at idle as well as under load. It may cost about the same as purchasing a cat and the car will perform much better.

Carl
 
You should first find the casue of your problem and NOT install a catalyst. You have a smell and there's a lot of good advise on how to get that fixed. A catalyst can get extermly hot and it could even be dangerous to have on one of these old cars not designed for it.
 
Hello everyone,

Thank you for the various replies. In looking into various other posts as well, adding a Cat would most likely be a poor idea. Clean air is a good thing, but potentially catching myself on fire would defeat the efforts. :)

I noticed that the body seal caulking in the trunk is getting cracked and hard. I also noticed that the trunk seal was not tight. I am going to start with plugging every air/fume gap from the exterior to the passenger area. I will also try synthetic at my next oil change to see if that is any help. I will look into high-tech tuning as well and see what I can find.

Thanks again for the replies.
 
Do you have any leaks in your exhaust system?Plugging,sealing any cracks or holes is sure to help,maybe even one of those turndown tips to extend your tailpipe away from the car?
 
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