'99 Motor Swap into a '91....a few Q's

So my '91 motor finally gave up the ghost. I've located a few nice '99's from XJ's but none of them are complete (for that matter, haven't found ANY year, lower mileage motors that are complete), meaning no AC compressor, alternator, starter or PS pump (I've located a PS pump and bracket/idler so I can use the newer intake).

I would like to know if I could mount my '91 alternator and AC compressor (my AC still works :yelclap: ) using my original brackets to the '99 block and have the drive belt line up? I'm planning on deleting the original idler and using the '99's.

I've checked online and noticed that the AC compressor, alt. and starter are different parts numbers between 91/99 MY's so I'm unsure if it's doable.

Should I go with the '99 starter or could I reuse my '91 (AW4)
I'm aware of the needed coolant sensor mod (thanks to ehall's cool thread).

Any other suitable candidates for that model year, Grands, etc?

Any heads up/advice/pointers on this swap would be much appreciated as I'm planning on getting a motor this Tue. and taking off from work next week to get her done...........my Heep is also my only car.......sucks not having transpo.

-Lou-

You can reuse your original AC, alternator, and starter. You ought to reuse them anyway so that all of the plugs and plumbing will still work (IE, changing to the later compressor will require new hoses). The big exception is that you will need to use a 96+ power steering pump since the tensioner assembly and mounting points are different and the old pump won't mount to the new intake. Everything else like sensors, ignition, injectors, fuel rail, etc., all needs to be from the 91 and will plug into the existing harness and plumbing. It's all pretty straightforward.

My additional advice is replace the rear main seal and anything else you are worried might leak later. It's a lot easier while the engine is already out.

ehall said:

You can reuse your original AC, alternator, and starter. You ought to reuse them anyway so that all of the plugs and plumbing will still work (IE, changing to the later compressor will require new hoses). The big exception is that you will need to use a 96+ power steering pump since the tensioner assembly and mounting points are different and the old pump won't mount to the new intake. Everything else like sensors, ignition, injectors, fuel rail, etc., all needs to be from the 91 and will plug into the existing harness and plumbing. It's all pretty straightforward.

My additional advice is replace the rear main seal and anything else you are worried might leak later. It's a lot easier while the engine is already out.

Click to expand...

Thanks ehall, best news I've had in a LOOOONG time! :guitar: Really appreciate your help.

Oh yeah, one more Q. What did you do about the drive belt, will a stock '99 work or did you use a different one (PN?)??

TIA,

-Lou-

I used a stock 99

Also make sure you use the 91 flex plate / flywheel - the CPS will be expecting to see that, unless you swap the CPS and ECU and all the wiring which is probably a can of worms you don't want to open. Using the 99 one might also affect the starter but I'm not sure.

Thanks for the info guys. I wouldn't have thought about keeping the original flywheel....good heads up on that one.

The JY called this morning; they had "issues" with the motor. Noticed a crack they hadn't seen before. Mmmmm'kay (????) whatever. So I'm looking for another suitable donor.

One question on engine removal; is there enough play/length to the AC condenser hoses to be able to move it out of the way without having to disconnect the hoses?

TIA

On a 91 I'm really not sure, be careful if they're rusty at all. On a 98 when I helped someone gut one it looked like it would be doable if you were careful.