skorpion

I'm about to score a 4.0 from a 1998 XJ that had 60,000 miles on the clock when it was pulled (the vehicle it came out of was rear-ended and totaled). My 1992 XJ has almost 366,000 miles on the original 4.0 engine. My current engine still runs great, so I am just buying the newer one to sit on for a while until this one eventually starts going haywire. When it comes time to do the swap some day, am I going to have any compatibility issues because of the difference in model years? I do most of my own mechanical work on my vehicles, but I've never done an engine swap before. Is there anything else I should do to prep the newer engine before I swap it in some day besides plugs, wires, distributor, oil, and a good cleaning? Thanks in advance!

trans_am7935

big thing is the head is differnt, there is no temp sensor on the rear drivers side so you will have no temp gadge. you have 3 opions:

get an aftermarket temp gauge
swap your head on to the new motor
drill a hole in the 98 head when the head is off the car

CodeXJ

You can also put a T on the front temperature sender and mount the gauge sender up there as well. That's how mine is currently setup, since the old one in the back of the head broke off flush.

Other than that, shouldn't be any huge issues, the engines are basically the same. You may have to use the sensors and the like off the '92.

Jeff H

I recently swapped a '96 w/92k into a '98 w/228k so I could start rebuilding the '98. The '96 had been sitting in a JY for who knows how long and I believe that to be the reason the lifters rattle at about 3.2k rpm.

Test drove an '01 yesterday with 74k on it (sat in a garage a lot for 9 years), and after it warmed up and ran a while (20 minutes or so) oil pressure dropped and it sounded lika a giant sewing machine. Sounded more like rockers than lifters, but if lifters are not pumped up the same affect occurs.

So, my non-expert first thought is that if I am going to have one sitting around or that has been sitting around, I would think about replacing the lifters before installing - unless someone has an idea about how to revive them. The '92 rattled at 2k rpm initially but now at 3.2k rpm, so they may have loosened up ove about 20k miles of driving.

Maybe someone else could chime in on whether sitting around lets the lifters start to stick or mot pump up.

skorpion

Thanks for the quick replies. Sounds like the temp gauge and having issues from the engine sitting idle for a long time may be my only major issues, then. Good to know! I may have to keep it stored outside, but it is in a crate and I can cover it with a tarp.

skorpion

Mine sounds the same way while idling after it's warmed up. A sewing machine is the perfect description for the sound it makes.

cheapJeeper

If it will be a sitting a while before you get around to installing it, you might want to pull the spark plugs, spray some WD-40 or light oil into the cylinders to prevent rust, hand-turn the engine a turn or two, and put the spark plugs back in. Also duct-tape off the intake & exhaust ports so moisture, spiders, etc. can't get in....especially important if stored outside.
Best of luck with your first engine swap!

CodeXJ

The lifters on these engines are just loud in general. In a V-style engine, the lifters are located between the cylinders down low under the intake, so there is quite a bit of metal between them and the outside world that absorbs and muffles the sound. On an inline engine, they are down low on the passenger side and right at the edge of the motor, so there isn't much between them and your ears.

Sitting for a long time, yes, the lifters could be gummed up. I'd seafoam the engine and see if that helps at all.

Jeff H

Good point.

Friday, I was comparing a number of them over the course of the day.
70k, '01 - sewing machine
133k, 99 - quiet as a mouse
100k, 96 - noise at 3.2k rpm

The ones that sat longer were louder. More used was quieter.
Not always the case either. I have heard a number of people say the lifters are noisy and alway roll my window down when next to another one at a light. Seems common but worse if they sit. Not very scientific, but I think I will replace the lifters in the one I pulled at 128k before I put it back in something.

Itis possible that the "knock" in that one was lifter-related, but I did not want to chance something really wrong happening. You won't pull one at a yard for just $500 forever.

skorpion

Well, no luck on the engine. Thanks for all the info anyway, guys. The seller I was going to buy it from sold it to someone else the day before and didn't even have the courtesy to tell me. I drove 40 minutes away and waited for 30 minutes for the guy until I called him to see why he hadn't shown up. Awesome way to spend one of my precious few days off.

JeepCoMJ

just drill and tap the head for the rear temp sensor. vacuum while you're drilling, start small, and work your way up.