Girlfriend's XJ - Stolen Cat

[shima]

This is as much for me to vent and to make fun of myself as it is to ask for advice...

A long-story made short:

• My girlfriend drives a '93 XJ. Her catalytic converter was stolen the night of Thanksgiving.
• In an effort to save her money, I told her I'd help her out and get it fixed myself. She can pay me back and I'm cheaper than a shop.
• I bought this catalytic converter off of Amazon and had a friend of a friend weld it on:
  • Due to where the thief cut, we did not have enough exhaust pipe on the upstream/inlet side to make use of clamps.
  • I had the guy weld only the upstream/inlet side and I planned to attach the outlet side to the muffler myself using clamps. The outlet side of the catalytic converter is supposed to slide into the muffler pipe.
• It has been a total b**** to get the muffler pipe attached to the cat. I've been hammering on the muffler from behind in an effort to join the two pipes.
• My original intent this morning was to create this thread to ask for advice on getting a male pipe (cat) into a female pipe (muffler). Use lubrication? Heat? Etc?

Well, that catches things up to this morning... I was looking at the catalytic converter info sheet and to my terror I saw that it is directional. The inlet pipe and outlet pipe are slightly different diameters. Why the hell would I assume it was not directional? What on earth was I thinking? Why didn't I spend more time researching before I had the weld done? I'm an idiot.

You can probably tell where this is going... I am now thinking that the catalytic converter is welded on backward, which explains why it is so impossible to get it mated with the muffler. I am going to go out into the garage tonight to confirm. If it truly is on backward, I guess I'm going to have to have the catalytic converter cut out and welded back in. Luckily the friend of a friend who helped me last time is a nice guy and doesn't charge much.

 

[swettysblazer]

Are you sure it's on the wrong way? The larger pipe end should go on the head pipe, with the larger pipe on the outside to help prevent a leak. You can get a sleeve from any local parts store to match the two pieces up assuming they are the same size, like this :



Or this:



I have used both of these- the clamp version is quick and easy, where as the actual pipe is a little stronger and will probably hold up a bit better.

 

[shima]

I need to go out and measure to be 100% sure that it is on backward. I am obviously hoping / praying that it is not.

According to this RockAuto info sheet, the inlet is slightly larger than the outlet. I am going to get under her Jeep after work and measure both to confirm.

If it is on the correct way then I suppose my original question would stand... but it has been so brutally hard that I'm guessing it is on backward.

Thanks for the pipe and clamp recommendations... if this thing is really on backward then I should probably sit down and plan a strategy to make it as easy as possible to get installed correctly. Her Jeep has been in my garage since Thanksgiving, which is just too long. Luckily she can drive my other vehicles in the meantime but I still feel bad.

 

[swettysblazer]

I need to go out and measure to be 100% sure that it is on backward. I am obviously hoping / praying that it is not.

According to this RockAuto info sheet, the inlet is slightly larger than the outlet. I am going to get under her Jeep after work and measure both to confirm.

If it is on the correct way then I suppose my original question would stand... but it has been so brutally hard that I'm guessing it is on backward.

Thanks for the pipe and clamp recommendations... if this thing is really on backward then I should probably sit down and plan a strategy to make it as easy as possible to get installed correctly. Her Jeep has been in my garage since Thanksgiving, which is just too long. Luckily she can drive my other vehicles in the meantime but I still feel bad.

Usually the larger end is the inlet end. This way the smaller pipe goes on the inside and allows the exhaust to go in, not around, the cat. If you have access to a welder, it would be easy to cut off, weld an extension pipe on, and reattach. I would go to an exhaust shop and get one of the ends flared and you should be good to go.

 

[shima]

Usually the larger end is the inlet end. This way the smaller pipe goes on the inside and allows the exhaust to go in, not around, the cat. If you have access to a welder, it would be easy to cut off, weld an extension pipe on, and reattach. I would go to an exhaust shop and get one of the ends flared and you should be good to go.

That makes sense, thanks a bunch.

I don't have personal access to that stuff, but this friend of a friend is down to help me out again if needed. He charged me $50 for the first weld, and the cat was $150... so I'm only $200 in so far. Even if he charges me $50 again then we'll still come out pretty decently.

 

[bigjimmy82]

Also, if you need to expand the existing tailpipe...autozone rents tailpipe expanders. $30 I think and they will refund.

 

[shima]

I took everything off a couple of nights ago. Measured the outside diameter of both inlet and outlet of the cat with a tape measure. It is confirmed... it is welded on backward.

The cat pipe end that is currently facing the muffler is about 0.25" to 0.5" larger than the cat pipe end that is welded to the upstream exhaust.

F*** me for not doing my research beforehand, but I guess this confirms why it was so incredibly difficult to get them to mate... and I learned a lesson here (the hard way).

 

[shima]

A while ago, I got the exhaust dropped off with the same guy who welded it the first time. Today, I was able to pick it up from him and it looks great.

He also cleaned up the muffler pipe end that mates to the cat. I had split it open trying to force them to mate.

Getting this job done is huge for me for a couple of reasons:

• It frees up a spot in my garage so that both squarebodies can be off the street.
• I am able to return my girlfriend's Jeep back to her, which means that I can get my Mitsubishi back from her. It is just as reliable as my Blazer so it will be great to have it back.
  • The Blazer is down right now due to a separate theft/vandalism.

I'm not worried about the Mitsubishi being on the street because it is too low to mess with. I run steering club locks on all of my vehicles as well so the chance of anyone screwing with it is pretty small.