Catalytic Converter rrrrraaattttle

[Jaime]

I hate working on exhaust systems, but I don't want to pay $500-$800 for a Y pipe + whatever it would cost for installation, so I've resigned myself to do this.

I'm thinking of cutting my existing cats of the Y pipe, getting a pair of aftermarket units and welding them in.

So far, I've found the following:

From Summit Racing, Catco cats CTO-6905 2 1/4 x 14 in. and CTO-6905R 2 1/4 x 12 3/4
http://store.summitracing.com/defau...eywordSearch&DDS=1&N=115&target=egnsearch.asp

And from Complete Exhaust, Imco cats 2505 (oval) and 2505 Round...and these have an O2 port.

http://www.completeexhaust.com/advanced_search_result.php?keywords=2505&Submit=Go

I have a 97 D1, so its OBD 2 with 4 O2 sensors. I have some questions:

Which are the correct or best cats for my application?

Can the cutting and welding be done with the Y pipe attached to the muffler and exhaust manifolds?
I'm concerned that I'd have to build some crazy jig to hold the y pipe in the exact position and orientation if I take the y pipe off the truck to weld on the new cats.

I'm thinking that the way to do this would be to leave the Y pipe attached, cut the old cats out, position the new cats on the Y pipe, tack weld them, then take the pipe off and finish the welding.

Any suggestions on how to do it?

Thanks

 

[barefoot]

easier to cut and weld with the y pipe on....although the passenger side weld is a pita due to clearance. dont have time to look through all those above, but the correct diameter is 2.5

 

[Lutzgaterr]

I second the tack-weld approach. I did use that approach and we had to weld and cut twice... what a PITA!

 

[Jaime]

Thanks on confirming the way to do it.

Do you guys remember which cats (part numbers) you used?

 

[D Chapman]

I thought you scored a new y-pipe at MAR for cheap????

 

[DiscoJen]

Tip

Don't forget to remove the O2 sensors before welding so they don't get too fried from the heat.

 

[Jaime]

I thought you scored a new y-pipe at MAR for cheap????

Yeah, so did I...but when I unwrapped it and took it off the rack, the cats were rattling


But Mike made it right for me.

 

[Jaime]

Don't forget to remove the O2 sensors before welding so they don't get too fried from the heat.

Thanks, good point.

 

[frickjp]

User "michael" had a good pipe removed from his Diesel conversion. BTW, which cat is rattling? I have a pipe around somewhere that has one good one on it. Easiest way to fit a new one is to remove the old pipe. Cut off the offending bits. Reinstall it. Tack the cats in, then remove the pipe and finish the weld. If it's just one, you can cut it off, cut the "newsed" one in the same spot and install it with a German exhaust coupler, like on an Audi or VW.

 

[Rocky]

If they are rattling live with it they will stop rattling sometime soon

 

[Craigness]

the end is near....

Yes, they will stop rattling.

When the completly break down and get siezed up in the bottom of the cat chamber blocking all the airflow.

Trust me on this one.

Drill about 3 3" drywall screws into the cat. That will last you long enough to source one on ebay or a junkyard.

But you should by a new one for $600. If you love the truck.

 

[Lutzgaterr]

or if you can gut these cats (depending upon your philosophy), single cut, gut the cats, tack-weld after reassembly and drop-down and complete your welds.

 

[Jaime]

easier to cut and weld with the y pipe on....although the passenger side weld is a pita due to clearance. dont have time to look through all those above, but the correct diameter is 2.5

I just measured, and the diameter is 2 1/4

User "michael" had a good pipe removed from his Diesel conversion. BTW, which cat is rattling? I have a pipe around somewhere that has one good one on it. Easiest way to fit a new one is to remove the old pipe. Cut off the offending bits. Reinstall it. Tack the cats in, then remove the pipe and finish the weld. If it's just one, you can cut it off, cut the "newsed" one in the same spot and install it with a German exhaust coupler, like on an Audi or VW.

Thanks, I think Michael already sold it. Looks like I'll have to remove the pipes completely anyway, so that seems like the logical approach.]

Yes, they will stop rattling.

When the completly break down and get siezed up in the bottom of the cat chamber blocking all the airflow.

Trust me on this one.

Drill about 3 3" drywall screws into the cat. That will last you long enough to source one on ebay or a junkyard.

But you should by a new one for $600. If you love the truck.

Yeah, I can put up with noise, but my concern was the blockage. Drywall screws sound like a good band-aid...gives me a chance to try out my new 18 volt drills (maybe even the right angle) that I got for Christmas!

 

[D Chapman]

I can't remember Jaime, but James Gall may have one???? Not sure if it still has cats, or if he even still has the pipe....