I have a 99 4.0 xj that needs a motor. I purchased a good running 93 4.0. What do I need to use off of my old engine?

 

Head, Exhaust, Intake and whatever sensors screwed into the block.

 

Head? Cant use the other head? Has to swap over?

 

Shouldn't need to bother with swapping the head. You WILL have to block off the port for the temp sender on the rear of the head though.

Best thing do do is use everything that's bolted to your old motor on the donor motor. Intake, exhaust, sensors, bracketry, flex plate (or flywheel) as it will have a different CPS than the 93 motor, distributor.

 

This^^,

 

Hey guys. This thread seemed pretty relevant. I have a '98 Cherokee Sport with a 4.0 5spd (AX-15). With only 107k miles, I discovered a crack in my engine block...I found a totaled jeep of the same year and model as mine with 93k miles, but it's mated to an auto trans.

I am assuming that I will swap the flexplate out of the new motor with the flywheel from the old motor? Sorry I haven't researched this part all that much. Just don't want to waste my time or money if the two wont be easily mated.

Any help would be much appreciated!

 

Correct! Use the flex plate from your current motor and swap it over to the new motor. Since it's the same year and motor, everything else is just plug n play.... you can pick and choose which parts from both motors to use. Whatever is in the best working condition.

I'd also suggest (if you have room to store them), salvaging everything off the old motor except for the block and storing it. Never know if you (or anyone else you know) will end up needing a piston, head, oil pan, whatever.... and just speaking from personal experience, you don't get squat for an engine block. I junked a 4.0 out of a '96 with the pistons, crank, cam, and a few other odds n ends and they only gave me about 20 bucks for it (weight of cast iron).

 

The donor motor will have all of the fresher parts: A/C compressor, alternator, water pump, coolant hoses. I will keep the spark plugs/wires/dist cap from the cracked motor since there is only 2k miles on them. I might get some vacuum lines, and other pieces that look nice. My clutch is great. Not going to bother with a new kit. I am being persuaded to change out he oil pan gasket and rear main while the engine is out...the motor only has 93k on it...with my luck, they will start leaking once the motor is back in and this will never end...

I got an engine hoist, and tranny jack with a garage space. Still waiting on the the donor jeep.

My E-fan wasn't coming on when the coolant temp sensor was unplugged, but I've never ran with temps higher than 210...unless that coolant temp sensor is bad....which might explain my cracked block....the gauge readout was always dead nuts on 210...you'd think if it was faulty, it would read something not so innocuous.

 

I believe the fan should turn on when the temp sensor is unplugged as the PCM has no idea of what the temps are. So it turns the fan on to keep the engine from overheating as a fail safe. I think.

 

Doing the pan gasket and RMS on an engine stand would be much nicer than under the Jeep with stuff in the way and oil dripping on you.

 

Invest in an IR temp gun. Aim it at the thermostat housing and then you can eliminate the guesswork. If the IR gun shows 210*, then you're good to go. If it's reading something else or fluctuating but your gauge is still sitting at 210*, then the sensor or even the gauge is bad.

x2 on this.

 

The IR gun confirms 211 at the sensor housing. I wonder what caused the damned block to crack in the first freaking place.

The dealership is draggin their feet on letting me get that jeep on location. I found another motor through this used parts retailer http://amuap.com/

Should I just order from another source or hold out for a motor that I can put eyes on before buying?

 

i would like to see a motor before i buy it. who knows, it could have been sitting outside in the rain.

you will need to install a pilot bearing in the end of the crank on an auto to go to stick.

 

Can I use the one that's in the original motor? I will be swapping the flywheel/clutch assembly to the back of the new motor.

 

i guess you can, if you can get it out without damaging it.

it is pressed into the end of the crank, it's not in the flywheel. but they're cheap enough to buy a few to leave in the parts box. that and the nylon pivot ball post along with retainer spring. providing it's an ax15