loligator

Hi all,

Looks like my 99 XJ has a bad motor. Drats. Luckily for me, I have a totaled 96 sitting in my backyard I haven't parted with just in case I needed something out of it. Looks like that day has come. The motor is in good shape though it's been sitting for about 2 years. I start it up about every 1-2 months and let it run for about 10 minutes so I know the donor motor should still be in good shape.

The first issue at hand is will the motor mount to the tranny? My understanding is there was a change made in the spline count sometime during 96. What I'm not sure of is if this matters in terms of swapping a motor. Is this something I have to worry about? If so, does anyone know at what point in 96 I'd be good to go?

I know about the temp sensor in the rear of the motor being eliminated and it's function being merged with that of the one in the tstat housing. The head was swapped on the 96 with a head from a 97/98/99 so that isn't going to be an issue. I'll be sure to keep the temp sensor from the 99 and move it to the 96.

The alternators have a different output for those years. Do I need to swap the alternator from the bad 99 motor to the 96?

From experience, I know a lot of the connectors for various sensors and what not are still the older style ones found on the 91-95 XJs. Is this going to be an issue?

Will the computer work as is? Anything special I need to have done?

Will I have problems passing emissions testing? I recall reading in the past that 99 and up have a redesigned exhaust manifold for improved emissions. Do I have to move this over to the 96 motor?

Is there anything else I missed?

Note the 99 XJ has a motor with the 0630 head and has a distributor in case that makes any difference.

Thanks!

Waynerd

Swap over all the sensors from the 99 if the connectors don't match. That should solve any of those issues.

salad

Straight swap. Use the 1999's sensors and accessories to be safe. Basic things like the temperature sensor will be fine. The intake manifold should be changed over as one piece, keep all the goodies that way. Crank and cam sensors show different part numbers. Not entirely sure why but I'd change them to be safe.

Fred/N0AZZ

Block is the same, head is not it was a better design and the mounting holes for acc's. are in different places. In addition on the 96 the exhaust is different as well.


If you could use or rebuild your 99 head/topend and use it with the 96 block everything will go together easier.


Cruiser will chime in I'm sure on the spline count. But can tell you the 99 4.0 was a single year build for several different things being different from 98< or 00> one of them being the better head design with a good casting #.

loligator

Thanks everyone for the input. I've never attempted a job so big before and being that is my daily driver, I'm def trying to get all my ducks in a row first if I decide to do this.

If not anything else, maybe I'll just get something else for the time being and make this a project. lol

Please keep the advice coming though if anyone has anything else to add. This is all very good so far.

salad

You might be thinking of the 1995 heads, 96 through 99 are 0630 casting

Fred/N0AZZ

My bad your correct was off a year on the head, its his intake that he should keep. The 96 had so many things changed yet many old ones still there at lot of surprises with it.

salad

Yup, I've personally seen three different 1996 builds. Different fuel systems in each one.

bluejeep2001

only thing you might have to do is put a plug in the sensor port for the temp gauge near the back drivers side of the head...early 96's had the sensor..later heads already had it plugged

Cane

is the 98 intake also a more desirable one like the 99

Waynerd

99 was the first year for the redesigned intake manifold.

Fred/N0AZZ

Correct the 99's were only year the 00-01's did not have a distributor.

Cane

alright cheers