Engine Swap: must A/C really be purged?

OK, subject Jeep is our '94 XJ with six and AW4/NP242. Decided just to put a Jasper reman in it instead of fooling with rebuilding myself, I think it's less hassle for us in the long run. Said engine for swap is sitting on a pallette in the garage, and I'll probably start this weekend. With the holiday, I'll have a week or so to do this, and I can swap mounts and other stuff while I'm in there. Sure beats trying to rush...

Looking at the FSM swap procedure, they claim that it should have the A/C evacuated and the condenser removed. I really don't want to do that if I can help it; obviously the radiator will come out, and I'll pull the other accessories before the swap. It doesn't imply that the grille/nosepiece needs to come off (if one was to take the engine/tranny out together, I'm sure that would be different; the transmission is fine, so I planned on just pulling the motor).

From casual obervation, it looks like I should be able to set the compressor aside without opening any lines, and I can't imagine that the condenser would be in the way. So it has me asking: Is this just a butt-covering step in the FSM, or is there really going to be an interference problem that I can't forsee?

The A/C works great and I don't want to mess with a good thing. If it really does need to be purged, I need to take it to an A/C shop with recovery equipment first.

Anybody tried this? Thanks...

It only needs to be purged if you open the system. If you can do the swap without opening the system, you should be golden.

Nope. Just did this - left the tranny in place and just pulled the engine, I pulled the A/C loose but I'm SURE there was enough room I didn't need to. Then was at a friends shop, and saw they just flopped the compressor to the side. Tells me it's a 7 or 8 hr job. .. Not for me! I'd put a piece of heavy cardboard over the a/c coil to protect it as extra insurance.

3XJFamily said:

I'd put a piece of heavy cardboard over the a/c coil to protect it as extra insurance.

Click to expand...

Hmmm, that's an excellent idea. Thanks.

After looking at the FSM procedure some more, it occurs to me that they're assuming removal of the engine with the accessories still attached to it. Under that assumption, then one would certainly have to pull the lines to the compressor. My intention was to remove all those accessories first (just set the compressor and the p/s pump aside) for more room to work with.

This does look a lot easier to do than the big-block V8s wedged in some of those late 70's GM cars...

Right - just flop it over the fender. Pulling the acc's is almost mandatory to have enough room to hoist out the engine if you've never done it - I have done other vehicles that appeared to have lots of room BUT each has it's little peculiarity.
Getting the engine at the correct inclination to mate to the transmission is important. The engine sling with angle adjustment by a long screw helps. Also, get long bolts the same thread as the ones in the bellhousing, cut off the heads, screw them on the new block and use them as alignment pins to mate the tranny. I also labeled ziplock bags with each component's bolts - very easy to remember what goes where buttoning it up.

A followup to all who replied, thanks!

Swap is now done, all looks and works great. It really took two people to hoist it in and out, one pair of hands to swing and twist the motor, the other to run the hoist. My wife got a kick out of running the hoist, and wheeling both motors around the garage.

All told, it took me about 30 hours work, but I really took my time cleaning stuff, brushing fasteners, anti-seizing bolts into aluminum castings, etc. Probably could have done it in 15, but I didn't want to have to re-do any of it for a long time.

Again, thanks all...

congrats! I wish I could get the ol' lady to help out....im lucky she knows where to put the gas...lmao