Replacing the Catalytic Convertor

[mluder]

OK... It doesn't seem like it would be that difficult but I've never done anything like this before.

The workshop manual doesn't seem to address it anywher I could find.
Is it a simple swap?
Is there anything special I need to do or just unbolt one and put on the other?
Anything to dress the gasket?

Steve

[DMCMW Dave]

Take off the muffler. One clamp and a bunch of bolts.

Take off the four nuts holding the converter to the crossover. They will probably break but you don't care.

Clean gasket surface on crossover

Put new gasket on converter

Assembly is the reverse of the above.

Worst part, if you have to deal with it, is the heat shield.

[Byrne H&A]

Your DeLorean may not need a converter if your local emission control accepts your vehicle as a classic. If accepted as a classic, put a bypass pipe in place of the catalytic converter and gain substantional horse power in return. If you need a preshaped bypass pipe, let us know as we remove catalytic conveters from all DeLoreans serviced in our shop. You will notice the difference from the first moment of acceleration. Byrne

[mluder]

I have a new heat sheild to so I guess it's a perfect opportunity to kill two birds.

Thanks.
Steve


Take off the muffler. One clamp and a bunch of bolts.

Take off the four nuts holding the converter to the crossover. They will probably break but you don't care.

Clean gasket surface on crossover

Put new gasket on converter

Assembly is the reverse of the above.

Worst part, if you have to deal with it, is the heat shield.

[mluder]

Nope - in Oregon it must be made before 1975 to not have to be tested. It does qualify for specialty plates as it's 30 years old but you are limited on driving. I get confilcting info on whether or not it has to pass emissions for these plates and I haven't gone to the DMV to try yet.

Besides, the gas fumes are really strong. While I know this won't entirely fix taht, I'm hoping it's a start.

Steve


Your DeLorean may not need a converter if your local emission control accepts your vehicle as a classic. If accepted as a classic, put a bypass pipe in place of the catalytic converter and gain substantional horse power in return. If you need a preshaped bypass pipe, let us know as we remove catalytic conveters from all DeLoreans serviced in our shop. You will notice the difference from the first moment of acceleration. Byrne

[DMCMW Dave]

Your DeLorean may not need a converter if your local emission control accepts your vehicle as a classic.

THis will probably open a can of worms discussion but....

AFAIK it's still a federal offense EVERYWHERE for a commercial shop to remove and not replace catalytic converter regardless of age/classic etc. Might want to check on that.

In general if you remove it yourself you won't get caught as long as you don't live in California or other perpetual emission testing states, but that does not make it legal.

I don't believe that this law has changed:

http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf

http://www.epa.gov/compliance/resources/policies/civil/caa/mobile/exhsysrepair.pdf

[vwdmc16]

changing the cat was the worse job on my car, the studs sheared so i now have nuts and bolts holding it, there is so little room to get a wrench in its such a nightmare.

[Delorean Industries]

THis will probably open a can of worms discussion but....

AFAIK it's still a federal offense EVERYWHERE for a commercial shop to remove and not replace catalytic converter regardless of age/classic etc. Might want to check on that.

In general if you remove it yourself you won't get caught as long as you don't live in California or other perpetual emission testing states, but that does not make it legal.

I don't believe that this law has changed:

http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf

http://www.epa.gov/compliance/resources/policies/civil/caa/mobile/exhsysrepair.pdf

Trailer the vehicle from the facility and the customer must sign a waiver stating the vehicle is intended for off road track use only.

[David T]

In New Jersey if it is not registered as a collector or historic vehicle it is subject to emissions testing which includes a visual inspection for the Cat. As I understand the law it is illegal to modify, tamper or render inoperative ANY emission control device. Federal law enforced by each State. Similar to messing with the odometer. Some are more strict than others. Also consider someday the car may be sold and it may wind up in a State where they are more strict about this than the one you are currently in. Or you may move to a strict State. Similar situation if you modify or tamper with any of the safety features of the car. Most shops will abide by the law, others are more willing to do what the owner wants. In the end it is the owner's responsibility. The good news is the older the car the less strict most States are. A Delorean in good running tune can run well with ALL of the emissions equipment operating. The best measure of that is keeping track of your gas mileage. If you are in the mid 20's MPG or higher you are doing OK.
David Teitelbaum

[Chris4099]

Steve,
When I replaced my system, the Cat didn't want to come out so easily. Even after snapping all four studs, the Cat did not separate from the cross-over pipe. I ended up having to take a hammer and pound on it for a good 15-20 minutes. Fortunately the exhaust system isn't fragile and you aren't saving the old Cat, so you can hammer on it pretty hard. Once the rust broke loose, the Cat comes right out and you can put the new one in its place!

Good luck!
Chris

[DMCMW Julee]

Trailer the vehicle from the facility and the customer must sign a waiver stating the vehicle is intended for off road track use only.

My conscience says no thank you.

[Delorean Industries]

My conscience says no thank you.


Cars for circle track, drag racing and basically any type of racing are extensively modified mostly by commercial shops to participate in these events. State laws simply prohibit the vehicle from being licensed by the owner for street use requiring transportation of the vehicle by other means. The professional method/ approach we suggest is exactly how it should be done. We as shops, Julee, are not responsible for vehicle owners' actions and what they decide to do with their cars post-repair. It is not illegal to sell components to remove emissions components but tampering is, if the car is to be licensed.

BTW this is simply a debate and not an attack on you or the subject:

-DMC sells converter delete pipes for the Stage I offering. It is unknown if installs have or will occur.

-DMC services Island TT cars with no converters and allows the vehicles to leave in a non-emission compliant form.

-DMC affiliate vendors also sell converter delete components to replace the factory converter with a test pipe.

Aside from your header system and our system, no other exhaust suppliers for the Delorean community sell a system in the United States that does not involve extensive tampering. DMC- Europe's does not use converters, UK Exhaust upgrade has no converters, Hervey's Chinese Special uses no converters etc. We all see vehicles with these modifications come through our doors and take no actions to make them emissions compliant. Is this something we should be guilty about as well?

So while I understand being righteous on the subject and would never help someone who was going to break the law with my assistance, we all push the boundaries to various limits in our own ways in this business.

You are only guilty with a conscience if you modify a car and then help the owner illegally pass state emissions testing. That would be wrong.

In closing-
-it is not illegal to produce the components for resale (we both do)
-it is widely accepted to look the other way (we both do)
-a federal offense can not occur without a paper trail. If the invoice doesn't state it happened, it is he said she said.
-owners are responsible for their own actions. We can not control their choices outside of our facilities.

Happy New Years!

[David T]

Companies sell radar detectors but just because you can buy them is no defense for speeding. We all do what we feel comfortable with and up to that point everything is fine till you get caught. Like letting R-12 loose and not catching it for example. A "test pipe" is sold for "testing purposes" and is not meant to be left in (Ha Ha). If we all followed every law life would not be as interesting but just be aware of what you are doing and make a conscious decision as to what side of the line you want to fall on (or over). Any small increase in power is not worth removing the cat. BTW in most States the PRV runs so clean you CAN pass emissions without it! Till they actually go looking for it! A better strategy would be to gut it and leave it in place. With no pre and post O2 sensors no one would know.
David Teitelbaum

[outatym2001]

Basically DMCMW Dave said it best above.
But, firstly open up the engine cover and remove the two bolts and remove the rubber/steel mount that holds the top passenger side corner of the muffler.
You can now back it onto some ramps or use my method of placing the rear on some jack stands.

Proper use of the floor jack and jack stands on the front and rear of the DeLorean.
http://dmctalk.org/showthread.php?1411-Proper-use-of-the-floor-jack-and-jack-stands-on-the-front-and-rear-of-the-DeLorean.

Next open the Parts Manual to page 1/5/0.
Remove item number 47, 48, 49, 50. On my D this clamp was incredibly rusted so I replaced it with a new one from either www.specialtauto.com or www.dmcnorthwest.com.
Make sure the old or the new clamp will fit around the replacement cat converter. If it doesn’t fit you’re going to have to figure out a way to make it fit.

Next remove the bolts securing the rubber/steel mounts from the bottom corners of the muffler.

Is your heat shield a whiter fiber board? The original white fiber boards are asbestos and if it is falling apart don’t use it. I replaced mine with an aluminum one for $72.95.
http://specialtauto.com/delorean-parts/engine.html

With a 12” breaker bar with 1/2” drive and a proper length extension(s) you can reach horizontally all four nuts holding the cat to the exhaust pipe. No need for any universal joints. I don’t remember the exact length of extension(s).

If the honeycomb matrix inside the entry point of your cat appears melted then you have been running rich for quite a while. This maybe necessary then to also replace your O2 sensor, also called Lambda Probe item 13 page 2/3/0.

The original gasket for the old cat will likely fall apart so make sure the surfaces are smooth and clean for the new gasket with your new cat. No gasket sealer is necessary.

During reassembly install all fasteners loose. Don’t tighten anything until you have both the cat and muffler hung in place including connecting those rubber/steel mounts. And then tighten everything starting with the four nuts at the cat.

[Doogie]

So, I have the original asbestos shield, as yes, it id falling apart. Having watched all the horror movies about asbestos removal over the past 20 years, should i even touch this thing? I want it gone, will replace with the really fancy Delorean shield, but don't think I should even literally touch it. How bad is it to actually remove? What have you done to get it off your car and disposed of? Am I being stupidly paranoid or cautiously safe?

TIA, Doogie,..new owner with "asbestosphobia" :mad1:

[mluder]

I too have the original asbestos sheild. Asbestos is only dangerous if the fibers become airborn.

My advice for removal. Wear gloves and at least a dust mask (you can by a cratridge style rated for asbestos if you REALLY want). Get a squirt bottle of water and completely drench the heat sheild. This will minimize airborn particles. Then proceed with removal. When removed put it in a plastic garbage bag and seal it off good. It is "supposed" to be disposed of in a certain way but that's up to you to decide...

My question is this... The asbestos was resistant to heat transfer - hence the term shield. How do the new metal ones work? It seems as thought they would absorb the heat and make things worse?

Steve

[mluder]

Thanks again for the CAT, Mark.

Wondering about your jackstand proceedure... I have four race ramp wheel cribs.
http://www.discountramps.com/wheel-cribs.htm
I assume the procedure is the same. Jack from the center of the frame front/back/both and put the wheel cribs in place and then lower the jack and remove. I think it sould be pretty stable at that point. I have some wheel chocks to throw on the fronts if I just jack up the back so I wouldn't think it will esacpe.

Thoughts?
Steve



Basically DMCMW Dave said it best above.
But, firstly open up the engine cover and remove the two bolts and remove the rubber/steel mount that holds the top passenger side corner of the muffler.
You can now back it onto some ramps or use my method of placing the rear on some jack stands.

Proper use of the floor jack and jack stands on the front and rear of the DeLorean.
http://dmctalk.org/showthread.php?1411-Proper-use-of-the-floor-jack-and-jack-stands-on-the-front-and-rear-of-the-DeLorean.

Next open the Parts Manual to page 1/5/0.
Remove item number 47, 48, 49, 50. On my D this clamp was incredibly rusted so I replaced it with a new one from either www.specialtauto.com or www.dmcnorthwest.com.
Make sure the old or the new clamp will fit around the replacement cat converter. If it doesn’t fit you’re going to have to figure out a way to make it fit.

Next remove the bolts securing the rubber/steel mounts from the bottom corners of the muffler.

Is your heat shield a whiter fiber board? The original white fiber boards are asbestos and if it is falling apart don’t use it. I replaced mine with an aluminum one for $72.95.
http://specialtauto.com/delorean-parts/engine.html

With a 12” breaker bar with 1/2” drive and a proper length extension(s) you can reach horizontally all four nuts holding the cat to the exhaust pipe. No need for any universal joints. I don’t remember the exact length of extension(s).

If the honeycomb matrix inside the entry point of your cat appears melted then you have been running rich for quite a while. This maybe necessary then to also replace your O2 sensor, also called Lambda Probe item 13 page 2/3/0.

The original gasket for the old cat will likely fall apart so make sure the surfaces are smooth and clean for the new gasket with your new cat. No gasket sealer is necessary.

During reassembly install all fasteners loose. Don’t tighten anything until you have both the cat and muffler hung in place including connecting those rubber/steel mounts. And then tighten everything starting with the four nuts at the cat.

[dvonk]

Am I being stupidly paranoid or cautiously safe?

its not paranoia if it can actually kill you, asbestos is nasty stuff. :nervous:

you'll want a P100 respirator, not just a 'dust mask.' the asbestos fibers that cause mesothelioma are microscopic and a little dust mask will not protect your lungs properly. i got my reusable P100 respirator at the local hardware store (Menards) for $40. im sure you can find them cheaper online. its great for other regular dusty jobs as well, and it also filters out chemicals & smells like ammonia, paint fumes, etc.

disclaimer: use at your own risk. be sure to read the precautions and instructions included with the respirator. :wink:

[Chris4099]

I assume the procedure is the same. Jack from the center of the frame front/back/both and put the wheel cribs in place and then lower the jack and remove. I think it sould be pretty stable at that point. I have some wheel chocks to throw on the fronts if I just jack up the back so I wouldn't think it will esacpe.

Just jacking up the rear should be fine. I assume your jack goes high enough to get those cribs under the wheels? You might want to get some jack stands for later so you can remove the wheels. They aren't that expensive.

If you like, you are welcome to come to my place where I have all the tools to do this. Only drawback is I'm leaving town for a week this coming weekend. So it will be two weeks before you can stop by (unless you come over on a weekday evening).

Chris

[outatym2001]

My question is this... The asbestos was resistant to heat transfer - hence the term shield. How do the new metal ones work? It seems as thought they would absorb the heat and make things worse?

Steve
We are somewhat at the mercy of what the DeLorean parts vendors sell. With my limited technical knowledge I read somewhere that aluminum makes a better heat shield than stainless steel. They are both rust resistant so I figured why not go with the heat shield I mention in my earlier post. Toby Peterson told me many full moons ago that he was working on what sounded to me like an exotic materials heat shield. I have not heard of any updates since then and the low price of $72.95 was right for me so I bought an aluminum one.
Something in my memory says the aluminum shield came with regular plated steel nuts and bolts to attach it. I’m pretty sure I threw those out in the recycle bin and bought all stainless steel nuts and bolts.


Jack from the center of the frame front/back/both and put the wheel cribs in place and then lower the jack and remove. I think it sould be pretty stable at that point. I have some wheel chocks to throw on the fronts if I just jack up the back so I wouldn't think it will esacpe.

Thoughts?
Steve

The difficulty is getting the frame way up high so that the wheels are up high enough to place those wheel cribs under them.
I use a small compact floor jack from Sears and it only raises the frame high enough to get a few clicks from the jack stands. I would like a huge floor jack but the compact one suits me just fine.

[SamHill]

If you look at what some people have done with their exhaust.... heat shields?! heat shields?! WE DON'T NEED NO STINKUN HEAT SHIELDS!

[TTait]

Getting to at least one of the bolts holding the cat to the crossover pipe can be really tough, especially in cramped quarters under the car. A combination of socket extensions and wobbly joints helps.

You should also consider why the old one failed. These are not a wear item. Either it shook itself to pieces or it melted internally because of fuel in the exhaust. You mentioned a gas smell - make sure you are not running too rich, or not getting good combustion, or you will melt down the brand new one too.

T

[mluder]

Thanks, Chris. I appreciate the offer and may take you up on it.

Honestly I should have all the tools here to do the job I'm just nervous about crawling under the car while lefted for the first time.

I bought the wheel cribs thinking it would be more stable than stands but you're right... I have to lift it pretty high to get them under. I started to try but then chickened out when I realized how high it was. I'm either going to try again or buy some jack stands.

I'm just concerned that jack stands could tip over. I know caution is always best but I'm probably worrying too much. Lots of people use them everyday and though there are incidents of falling cars they are not that common.

I just need to do it the first time and I think I'll be fine. The good thing is, once I get it on stands, I can geta bunch of necessary work done - Oil change, Heat shield, and the cat conv.

My next house will have a sho with a lift... :thumbup:


Just jacking up the rear should be fine. I assume your jack goes high enough to get those cribs under the wheels? You might want to get some jack stands for later so you can remove the wheels. They aren't that expensive.

If you like, you are welcome to come to my place where I have all the tools to do this. Only drawback is I'm leaving town for a week this coming weekend. So it will be two weeks before you can stop by (unless you come over on a weekday evening).

Chris

[mluder]

That's definately a concern... I failed an emissions test on high hydrocarbons so I used a dwell meter to get the mixture dialed in. MOst of the time it sits right in spec and every so often I get these severe swings high and low. After I adjusted things, I failed a second emissions test but the hydrocarbon count was better.

I pulled 4 of the 6 spark plugs and they seem fine.
I have not checked injector spray pattern.
I think I have a vacuum leak somewhere but haven't tried a smoke test to pin it down.

When I bought the car it had sat for ten years. The PO had Toby rehap it to get the fuel system, cooling, and breaks working. While most of the fuel system is new (pumps, wires and plugs, etc) they stopped short of replacing the injectors. On Toby's advice I ran Seafoam injector cleaner through over the course of about 6-8 tanks of gas and did some "spirited" driving. Not shure if it helped or hurt.

Needless to say, I have some proceedures I probably need to go through to really address the situation.

BTW, the old one is in really rough shape - the outside is really rusted over and caked with red dust. The car had been in Hawaii for it's entire life and I am finding this red volcanic rock dust everywhere.
I would bet the insides are shot too.


Getting to at least one of the bolts holding the cat to the crossover pipe can be really tough, especially in cramped quarters under the car. A combination of socket extensions and wobbly joints helps.

You should also consider why the old one failed. These are not a wear item. Either it shook itself to pieces or it melted internally because of fuel in the exhaust. You mentioned a gas smell - make sure you are not running too rich, or not getting good combustion, or you will melt down the brand new one too.

T

[Chris4099]

I'm just concerned that jack stands could tip over. I know caution is always best but I'm probably worrying too much. Lots of people use them everyday and though there are incidents of falling cars they are not that common.

....

My next house will have a sho with a lift... :thumbup:

If they are properly placed and the ground is stable, you've got nothing to worry about. The weight of the car does a good job keeping them in place!

I just moved to a house with a 3 car garage. So I'm looking into getting a lift myself. Just need to verify the floor is thick enough to support it.

[TTait]

I just moved to a house with a 3 car garage. So I'm looking into getting a lift myself. Just need to verify the floor is thick enough to support it.

You may be able to add steel plates under the lift to spread the load, ask the manufacturer. The other concern is whether your garage has a post tension slab with cables running through it. If you hit a cable, or even nick it while bolting it down you will have a problem.

[Ron]

If you look at what some people have done with their exhaust.... heat shields?! heat shields?! WE DON'T NEED NO STINKUN HEAT SHIELDS!
When does it end?7588

[nofear365]

How much different is the exhaust note without the cat installed? I'm really interested in this modification.

[pezzonovante88]

How much different is the exhaust note without the cat installed? I'm really interested in this modification.

+1

[Ozzie]

How much different is the exhaust note without the cat installed? I'm really interested in this modification.

I don't know the answer to that but I will add this:

I have been running the (stainless) DMC Stage 1 system for a while now, and it has dual cats. One of the most enjoyable parts to me of the Stage 1 system upgrade (and I expect other similar ones), is the burblling sounds between a high rev 1st to 2nd shift, that come from the unburnt gas mixture going off in the cats.

I would miss that sound very much, if I took that cats off.

[nullset]

Like letting R-12 loose and not catching it for example.

Have you seen how expensive R-12 is these days? :)

I'll gladly evacuate R-12 legally and safely for any owner that can get their car to me in Atlanta!

--buddy

[Ed81DMC]

Steve,
When I replaced my system, the Cat didn't want to come out so easily. Even after snapping all four studs, the Cat did not separate from the cross-over pipe. I ended up having to take a hammer and pound on it for a good 15-20 minutes. Fortunately the exhaust system isn't fragile and you aren't saving the old Cat, so you can hammer on it pretty hard. Once the rust broke loose, the Cat comes right out and you can put the new one in its place!

Good luck!
Chris

Chris - many thanks for your post. I too a having trouble pulling the cat off after shearing off all 4 flange bolts.
I was searching for a hidden bracket or something but in every article I read the cat just magically falls out.

Now I can pound in it without worry.

Just how did you apply the beating?
I’m thinking of an air chisel against the cat flange.

I did have one stud that didn’t shear off so I tried threading a nut on it and pounding on that nut using a steel bar but I can’t get enough swing on there to hit it very hard.

I guess another way is to pound on the broken studs because THEY ARE THE REASON THE CAT WONT COME OFF! The studs are rusted tightly in the crossover pipe flange holes! Maybe I’ll use the air chisel (with a small round blunt tip) directly against the broken studs to push them out of the crossover pipe flange holes!

[Chris4099]

Ed,
Honestly, I can't remember exactly how I did it as it's been about 8 years now. I can say I didn't use any power tools, just a standard hammer. Since it was rust holding it on, I probably just hit it from above and below to break it loose.