catalytic converter on a 1976 eldorado

[76 cadillac bob]

My mechanic is going to remove the inside of my CC, is there a way I can do it myself? We will leave the shell, for appearances. 
Regards
Cadillac Bob

[Big Fins]

Having no emissions requirements in Florida, mine has been simply removed. It made a huge difference in the way the engine breathes.

[Jeff Wilk]

Are there many States that still have an emissions test for properly registered Classic Cars? I’m not sure but I thought even very stringent States like NJ, NY, and CA did away with that. If so in your State cant you simply take its pellets out though the plug?

[jagbuxx #12944]

California requires smog check for 1976 and newer

[Big Fins]

If the Cat has a good case, you can take the pellets out. Removing the plug may be a job though. It's been rusted in place by heat near 1000^oF for years. The case on mine was like Swiss cheese.

[Dave Shepherd]

Be careful handling those pellet's, mask and gloves.

[bcroe]

When upgrading/replacing the exhaust (to stainless steel) of my 70s cars,
the cat was replaced with a monolithic type.  This was considered legal,
effective, and passed many inspections in IL.  Monolithic is much more
compact and has much less back pressure, esp against an old original. 

This plan pretty much implies a single exhaust, I used 2.5 inch for small
block and 3 inch for larger.  The improvement in performance was
noticeable, the increase in noise was slight.  Bruce Roe

[76 cadillac bob]

Hi all
I live in Idaho now and classic cars of this age do not require emission testing, I lived in Calif and it was a B_ _ch to smog, my wonderful mechanic tweaked it to pass.
I had the whole exhaust replaced 3 years ago so it is relatively new. The heat from the CC really gets the cabin hot so doing away with it will solve many issues.

[hornetball]

Those early catalytic converters were very inefficient and restrictive.  Plus, the cars didn't control AFR very well, so they tended to clog and burn up.

I think catalytic converters (especially the new ones) are darn near miraculous devices and I try to install newer technology ones if the car originally came with one.  But on a machine without EGO feedback (like a '76 Caddy), I think it's a waste of time as their life will be short.

[bcroe]

In emission testing days, I found a new monolithic converter on a
79 daily car, gave good test results.  2 years later it was poorer,
and more so in 4 years.  After 6 years I put on a new one and the
car went back to the original good results. 

I purposely moved out of the testing area, but soon after the state
dropped testing.  Good move, the new cars were so good that is
was a waste of time.  Bruce Roe

[toukow]

If the Cat has a good case, you can take the pellets out. Removing the plug may be a job though. It's been rusted in place by heat near 1000^oF for years. The case on mine was like Swiss cheese.

I did this on mine a few weeks ago. I hit the plug with Kroil and tapped with hammer, repeat. Let it sit for day and used a breaker bar with extension and it popped loose. Obviously a case by case situation, as I can see how it would be easy to destroy the housing if degraded. Used the shop vac with a piece of 5/8" hose to suck out the beads. Used a mask, and should have used gloves as recommended. Have a large garbage or other suitable container underneath to catch the spillage. Dean

[76eldo]

I solved that problem by putting on a 71-74 exhaust system.
Between that crazy cast iron box that goes into the convertor and the convertor itself there’s a lot of restriction there.