I screwed up. I changed the engine in my 90 V-12. Not my first time doing an engine swap on a v-12 XJS. Usually I take some safety wire and secure the front cats so that they are in approximate location. This Time I did not. I have been trying to fit the left front cat, but can't get between the steering rack and the frame. I took the heat shield for the rack boot out, but do not see clearance.

What am I missing?

 

why not take them off and not worry about it.

 

And connect the exhaust manifolds to what?

 

The rack needs to be moved down out of the way, and for more room, the subframe mount may need to come out. Or drop the rear of the subframe down. It's tight even with straight downpipes. More so with cat downpipes.

 

Are you talking these evil things? To get these out, if you've got the damn 2nd cats you've gotta drop those and the intermediates, otherwise just the intermediates. To get them back in, I get the downpipes on the manifold with two helicoils that aren't the heat shield ones. Then I get the heat shield in place and do the other two helicoils. Then I just rotate around tightening things - you can screw this up if you don't do an even tightening. You'll end up with the down pipe not sitting properly. I just screwed this up, so it's fresh on my mind The front pipe is about 1/4" lower than the rear pipe - check pic...

 

To these sort of non-cat downpipes

 

What Greg said. i just pulled a set off a parts car like this. No Cat's what so ever. We did have to take the downpipes off to get the motor out. Just no room to clear the front sub-frame and steering rack otherwise.

On my own car I know I removed both sets of original Cat's. I didn't wait for them to go bad from age.(A friend with an XJ6 had his Cat's go bad. We couldn't figure ut wy the car wouldn't start. Turns out it couldn't breathe at all from the Cat's crumbling on the inside) I replaced them with only one Cat on each side. I also removed the rear resonators. It's not dramatic but there is a noticeable difference in power. I personally like the low grumble sound the car now makes as well. It's a V-12 after all. It should let people know there is something special in there. .

 

If the resources are available I would lose the CATS all together and even break out the combing at the top of the replacement downpipes if they have that when you get them. Makes for a lot more room.

I think if the heat shields, oil filter and shaft for the steering are moved and removed (all from memory) the cat on the LH side can be moved up, fitted and refitted. The RH, again from memory, by comparison has lots of room.

 

Steering shaft was the issue. Disconnect that and drop the steering rack and it might come out easily.

 

Dropping the steering rack gave me enough clearance. Of course the next fun job will be getting the steering rack shims back in place as I reinstall the steering rack. Thanks everyone for the advise. It was spot on.