1976 eldorado cutting out and cleaning out the catalytic converter

[76 cadillac bob]

Greetings all I am finally working on car as snow is due here in Idaho. Question: The engine compartment is overheating from the Catalytic Converter (I think)....the engine is not internally hot but the rear fire wall wiring almost melted and almost caught fire from heat coming from the CC...The  muffler at rear of car is cold.
Zinc additive and  Sea Foam was added to engine (engine was rebuilt about 10 year ago before I bought it.... did it destroyed the CC? I am going to take the thing off myself and put on a straight pipe. Does this sound like the CC is the problem before I go through the exercise of cutting it out?  I cannot take the car out of the driveway the firewall and anything above the CC gets blazing hot real fast. Engine starts perfectly well, runs great for the little time I run it. Manifolds are also looking like internal heat is building up badly, they look scorched.
Thanks for your assistance.

[TJ Hopland]

Blocked exhaust engine will usually run fine just won't make power and will make the the exhaust hot.   Cats can easily plug up if the engine wasn't running right at some point.   Don't overlook the muffler either.  Original mufflers had an insulation material in em held in with a steel mesh that can rot and let the insulation plug up while still looking new on the outside. 

[76eldo]

Get did of the convertor and the stupid cast iron box in front of it that the exhaust pipes are going into.  I have a 76 and put a 71-74 exhaust system with the resonator and it is free flowing and quiet and has a lot more mid range torque.

Sounds like your cat is clogged to me. 

[cadillacmike68]

Get did of the convertor and the stupid cast iron box in front of it that the exhaust pipes are going into.  I have a 76 and put a 71-74 exhaust system with the resonator and it is free flowing and quiet and has a lot more mid range torque.

Sounds like your cat is clogged to me.

You are aware of course that you are telling the OP to break federal laws.

[dennisspeaks]

good luck neighbor.  I feel your pain, we have snow here in Spokane,~

[Daryl Chesterman]

Bob, do you have to do an emissions test to license your car in Boise?  If you do, you will probably be required to have a catalytic converter on the car.  NAPA, and other automotive parts jobbers, have universal catalytic converters that cost around $100.  If you have a wire-feed welder, or an oxy-acetylene torch, you can install it yourself.

Daryl Chesterman

[fishnjim]

If ZDPP or similar was put in the oil, there's a slow loss, ~5%/1000 miles, that occurs and would go out through the breather/PCV to intake.   Zn will coat the catalytic surface and render inoperative.   That's why they got away from or reduced the levels of some of the old additives going forward.   
Any lead replacement gas additives will also be bad here.  But '76 is well into the low compression daze negating its need.   One used to be able to buy the pellets to recharge the early cats, but I haven't kept up with that stuff.   There was a plug in them.    Lots of them were stolen when the metal prices spiked in that period due to high demand for new.   The current ones are quite compact compared to the early versions.   {aside;I later worked with one of the inventors of the GM cat convertors, now deceased.}
Excessive heat; Sounds to me like your heat shield is missing or rotten(floor?).   They put shields in, then found they could cause fires if parked over combustibles, like grass, etc.
ps: They don't like to run too rich either, as more fuel means more heat.

[76eldo]

Removing the cat on a 76 car is breaking federal law?
Better call J Edgar Hoover on me then.

I’m in PA and antique registered cars are exempt from any emissions testing.

[TJ Hopland]

Lack of an inspection where you live doesn't change the law.   

I don't think there is a direct bolt in option available for these cars so pretty much no matter what you do there will be custom work.   I'm sure you could do it with flex pipe and band clamps but someone that can bend and weld would be ideal.   

Its been a while but pretty sure the engine side was a flange that bolted to the crossover manifold thing.  Wasn't the rear a flange too?   And there pretty much wasn't any pipe between the body and flanges so you can't easily re use them.   

[Big Fins]

Removing the cat on a 76 car is breaking federal law?
Better call J Edgar Hoover on me then.

I’m in PA and antique registered cars are exempt from any emissions testing.

I really tried to keep quiet over that one.

Just like Mike, I'm in Florida with NO inspections and nobody peeking under the car to see if the cat is there. I pull them off of every pre-77 car I have ever had.

As for the big cast iron collector, I left mine because it was in such good shape. I do the exhaust from the collector back in aluminized steel and it lasts far longer then the car. My car runs better than it did from the factory and is just as quiet.

[hornetball]

Get a laser-dot temperature gun.  With engine running, if there is a big temperature drop between the entry pipe/exit pipe, then your cat is a goner.  With a correctly operating cat, the temperature will be about the same or will increase (due to the catalyst action).

The temperatue gun can also detect a clogged muffler.  And, if you have a misfire, you can find the exact cylinder by hitting the exhaust ports on the head.  Great tool!

[signart]

You don't need to eliminate the cat. Gut the cat.

[76 cadillac bob]

Thanks all, yes it is a Federal Offense to remove it, can I say the Feds can go ____ themselves? I am not an anarchist, just a passionate car enthusiast; There are far more important things that need to get done within our government than worrying about one little converter on a car that gets driven maybe 50 miles a year.  We have no inspection in Idaho for older cars so I am clear in that manner. I may try to cut it then gut it out as a "dummy" we will see. I can have someone weld it on.
I am leaving the square connector for now but know getting an older one allows for better flow.
I just checked and cutting on the back side of converter is easy, wondering does the converter fit "over" the exhaust pipe or just attaches with weld to it end to end? It is important to know as I dont have much room from square box to the converter to cut out.  I can remove flange from square box if bolts are not too frozen, prefer not to disassemble the whole thing keeping it simple as possible if it aint broke dont touch it.

[76 cadillac bob]

AS an aside to my prior message.....newer car catalytic converters are being stolen at the rate of 500 a month in Seattle. I jokingly told a friend, maybe I should just take it there, leave it on the street for a day or two....problem solved...alas, they would most likely steal the whole car....not a joke.

[hornetball]

Hasn't Seattle cut their police force dramatically?

[Big Fins]

This is for Seattle.

https://www.youtube.com/watch?v=7TLqfnwFd3o

[EAM 17806]

Removing the cat on a 76 car is breaking federal law?
Better call J Edgar Hoover on me then.

I’m in PA and antique registered cars are exempt from any emissions testing.

No emission testing doesn't mean you don't need a CAT converter; Federal law requires all cars that came from the factory with one must still have one, so let us all obey the laws for a change and keep all our health protected as much as possible.  EAM

[76 cadillac bob]

last response made me rethink, what I intend to do is eventually replace CC but need to get oil changed and fresh fuel so a new one wont plug up. In the meanwhile I will put in a temporary  pipe where old converter was and drive the car. Too cold and rainy here in Boise now but down the road will get her out and figure out next project of which there are many. Thanks all for your input and having travelled the world, there is no place like America.

[76eldo]

My 76 only sees about 500 miles a year.
I have no regrets about losing the convertor and changing to a 71-74 exhaust system.
If I was using it as an everyday car that would be different.

[cadillacmike68]

Removing the cat on a 76 car is breaking federal law?
Better call J Edgar Hoover on me then.

I’m in PA and antique registered cars are exempt from any emissions testing.

No matter what local testing requirements are, Federal Law prohibits removing or tampering with ANY part of a car's emission systems.

I'm not telling anyone here what to do or not to do, just what the facts of the laws are. If you have no testing requirements fine, some states will STILL look for the parts on the cars. Do what you want.