diskman

I have a '92 XJ with 250K miles and unfortunately the oil pressure is about 3 PSI to 10PSI hot. Soooo.. I called around and found a 99 4.0 complete with just under 100K miles for reasonable with a 6 month warranty.

I am assuming that the 99 will bolt right up? Except for the 99 intake/ps pump exchange and any sensor work would this be a direct install?

I was considering building a stroker, but I found the 99 motor instead.

Any input on this?

ltlgreenXJ

umm, guys, correct me if i'm wrong, but the 99 was distributor-less. so youll need the 99 ECM with it. other than that i think you'd be golden.

REWSTER

I thought it was 2000 that started the coil pack

diskman

'99 still has the dizzy. 2000 is when they moved to COP. I have a '99 XJ also and it has the dizzy.


So, the '92 tranny will bolt right up to the 99 4.0 crank and all? I would hate to be blindsided by some Chrysler change during the years.

5-90

Oil pressure problems will be found in the short block (use a quality filter, use the proper viscosity of oil, or check bearing clearances.) If you're replacing to fix the oil problem, just swap out the short block and use the original head.

The 1999 short block will fit under the 1992 cylinder head without any trouble. Which head you'll have on the 1999 depends on the model it came out of - the 1999 WJ and TJ had the 0331 head with the DIS/COP ignition, and the 1999XJ had the 0630 head with the distributor. The cam sync assembly and distributor will swap easily.

Also, the ports on the 1992 head flow better than the 1999, so you'll probably want to stick with that anyhow.

Are you close to San Jose, CA? I need a 0331 head or two for research purposes, and even shipping them Greyhound or Amtrak gets spendy!

diskman

The engine I would be getting is out of a 99 XJ so it has the dizzy. I wasn't planning on swapping heads as the new motor has less than 100K on it and I *really" hate to mess with it if it's not broke. Besides, I would need to freshen my '92 head I am sure and I am sorta on a budget for the time being. I am getting the intake and exhaust manifolds still on the new motor too so figure I will be gaining the 99 intake. woo-hoo! Just need to get the '99 PS pump for the 99 intake bracket I guess.

I will probably tear down my '92 4.0 just for giggles once I get it out. I will keep the head from my '92 in storage just in case I ever build a stroker or need one in the future. If I *DO* ever build a stroker, I will source a 96-up block as they had extra re-inforcements and the mains-girdle.

My '92s oil pressure was probably due to the original owner not changing the fluids. When I got it last fall, I changed out everything. The coolant was original, the ATF was original, the brake fluid was original. The oil was black as midnight. Surprisingly it runs very smooth and burns/leaks NO oil at all. Kinda shocking with my 3/10PSI pressure on such a fine running motor. Gets excellent MPG too. Kinda sad about the previous lack of maintenance.

jaqattack02

If it still runs well, are you sure the oil pressure on the gauge is accurate? Are you getting any odd noises out out of it? If not, I'd give replacing the oil pressure sending unit a shot before I went to the trouble and expense of swapping the engine. From what I've heard that sender can be a little sensitive and can show inaccurate readings after being knocked once or twice.

diskman

Ya. I replaced the original sending unit back in November sometime since I was running 10/20PSI on fresh 15w40 Rotella in cold weather.

Since the other day when I hit 3PSI or so at hot idle, I picked up a $16 oil pressure gauge and slapped that in place of my sending unit. Yup. Barely 3-5PSI at hot idle and maybe 18-20 if I spin it up to 2000-2500 RPM in park. It IS due for an oil change in another 500 miles or so (4k changes) so I will probably replace with 20w50 and see what happens. Cold PSI is about 15PSI idle and 25-30 at about 1500RPM on the highway till it warms up. Then it drops.

The engine sounds great though. Still pulls great and no odd noises. No oil leaks/significant blow-by. There is a slight lifter noise at hot idle when I am pushing the whopping 3-5 PSI but it's not as bad as my old '64 Plymouth 225 noise or the bad lifter in my '99.

Was considering replacing the oil pump with a new Melling high volume pump. That might bring up my pressure a tad due to the higher flow rate.

Who knows? With the new pump and assorted BS that will need to be done that way, I am about 1/3 of the $$ towards the new low-mileage '99 motor thats guaranteed to last me quite a long time. Hmm.. New oil pump in my 92 as a gamble? Or a low milage motor instead. I know which one is easier to do in a weekend though..

5-90

Whenever you get a suspect gage reading, it should always be verified independently.

Silly voltmeter reading? Back-check with a DMM.

Don't like your oil pressure reading? Back-check with a mechanical test gage.

You get the idea.

jaqattack02

If it isn't showing any signs besides the oil pressure, I'd let it go till it did, unless of course it's your only means of transportation. Just drive it till it starts knocking or something, especially if you're just gonna yank the engine eventually anyway.

diskman

I picked up some Castrol 20w50 last night at Wally-World. They had the 5 qt jugs for 10 bux! I should go back and get more. I see the Mobil 1 went back down to $22 also. I run M1 in my '99 XJ.

Need to goto Napa and get a filter or two today though.

sandstone

x 2

Yeep13

x3 dont fix it till its broke!, take the time when its dieing to work on the yard motor your picking up

5-90

You may need to "freshen" the earlier head, but don't do it unless you plan to "freshen" the block as well. Cleaning up a head and putting it on an old short block usually means blown rings, cleaning up a short block and putting an old head on it usually means you'll lose valve seal. It's a balancing act.

(And, if you're not going to have the head stripped and redone totally, I've noted that a simple re-ring and hone will usually serve to preserve the bottom end.)

Just move the head over to the new short block, and call it good. You can move the intake over as well, if you like, since that's not a "sealing" issue WRT compression or combustion.

fasteddy10

Mid 2000 and up for the coil pack head. 2001 block and older will work. You will have to change periphials on most of the year differences though. (manifolds, sensors harnesses etc.) Newer blocks are missing the bracket mounting bolt holes you need for the Cherokee on the right side of the engine block, and the timing case cover. The electronics and ignition is a major concern on almost every year different than the one you have, regardless of the year your working on. Generally the engines fit into four ranges. 95 and older 96 through 99 & early 2000, and then mid 2000 and 2001. Then 2002 up. There are many pieces of good advice withn these Forums. Take the time to read them. I just finised a swap on a 2001 Cherokee using an early 2000 engine. It worked, but had to fabricate brackets to hold the Coil Packs in place, and change all ignition parts from the 2001 to the 2000 engine, and the exhaust manifold with the dual Cats.