Geonovast

Hell creek has AALs and full packs. Full packs > AALs. Last time I looked, IIRC, full 3 inch packs for the MJ were about $350 for both sides.

Leaking what?

Never seen an LP 99.

Head was changed mid year. Look on the head, manifold side, on the top between (IIRC) the #3 and 4 intake ports should be the casting stamp. Early 99s had the 0630, later ones got the cracking 0331. My 99 has a build date of 8-98 and has the 0630.

I think it would be worth more if it was rust, since you can make out Cherokee Chief in it.

The 12 point head bolts is something somewhat new. Every late 80s/early 90s 4.0 and 2.5 I've worked on had 6 point head bolts.

Well then, guess your motor is kaputt. I don't think the transmissions are date coded. Unfortunately my spare AX-15 just made a 500 mile trip to my brother's house so I can't check.

If you have an external slave, then yes, either someone put the external stuff onto the original transmission, or it's not the original trans. There's really no way of knowing for sure what pilot tip size you have without yanking the trans or motor. 4.0s are pretty tough. Your motor may just need a little TLC as mnkyboy suggested. Since you think it's dead anyway, it can't hurt to take it apart in the truck and poke around.

91 won't be an external slave. They didn't go back to externals until mid 93. It is entirely possibly that someone put an external bellhousing, bearing retainer and clutch fork on a 91 trans, but it wouldn't be factory.

Really the only issue with using the bushing that sits further back, is it's awfully close to the splined part of the input shaft. I imagine that's the issue people have run into. The pilot bushing/bearing keeps the input shaft centered when you push in the clutch. With the clutch engaged(pedal up), the motor and input shaft are spinning at the same speed. But when you push in the clutch, they're no longer spinning together, so the input shaft has to have something to ride in.

Remove relay. Plug vacuum lines. Remove pipe and plug holes. Motor should be fine, they ditched the EGR in 91 anyway.

Your head ports should line up just fine. CPS isn't an issue. It bolts to the transmission and reads pickups off the flywheel. A newer flywheels should work fine with no issues, at least the 91 fly in my brother's 98 is working great. Just be sure to remove the CPS before pulling the motor and reinstalling it after the motor is in to ensure you don't break it. New ones are pricey... Especially since 91 used its own plug. Plug and sensor were changed in 91 with the HO system, then they changed the plug again in 92 for some reason. The 0331 head casting (99 1/2+) won't have the threaded hole in the back for the gauge's temp sender. This head is also prone to cracking. You should look for a 91-early 99. I'm not sure how long the dizzy from 91 was used, but it was definitely changed in 97. I think every sensor was changed in 97, but you'll want to hang on to all your 91 sensors anyway in case you need to use them. That pilot bushing you put up may work, but it sits further back in the crank than the OEM location. There's essentially two bores in the crank, you could use either one. Personally I'd use the deeper one if possibly, but using the one further back should be fine.

You would think.. but no. See, in 92, they didn't just change the size of the pilot tip. They also changed the size of the bore in the crank that the bushing gets pressed into. Pilot bushing dimensions : I.D. O.D. 87-91 0.586" 0.872" 92-06 0.75" 1" The 87-91 motors also had a brass sleeve that the bearing itself was in, so the crank bore on those is actually bigger than the 92-06 motors. Can't find a dimension on the actual bore, though. Basically, if you get a 92+ motor, you'll need to get a bearing or bushing with an OD of 1", and an ID of 0.586".

Can be bypassed. :brows:

You could probably make a not-to-bad looking one if you had two front bumpers, and cut them so when the long sides were attached they were the width of a rear bumper. Just don't use chrome. :ack:

Obviously 1991 would be your best option, but later years will certainly work. Anything up to 98 would be simple. As you may know, the pilot tip size of the AX-15 and bore size in the crank weren't changed until 92. 91 is kinda a crappy year to have. Putting a newer trans(92+) behind an older 4.0(87-91) is easily fixed with the 74 CJ 304 pilot bushing. I am not aware of a bushing that will easily allow you to put an older trans behind a newer motor. I (without much difficulty other than dealing with the wrong bushing) put a 91 4.0 in a 98 XJ that exploded the #6 piston. That 91 motor is purring along in the 98 just fine. The cam was changed around 96 I believe, but it shouldn't change anything. Just make sure you hang onto all your 91 sensors. You will definitely need your 91 CPS, and you may need to put your 91 distributor in the replacement motor.

You should start calling it a "downdate" Pete.

Never done that to me, may be a problem with your computer though. Fire up another browser and see if it does it.

If only there were a form that you had to fill out for the classified section... requiring you to post location, price, etc...

If you know he wants a PS3 and not a 360, then that would of course be a good present. I would get him one or two more games though, maybe hit up the cheap used box at Game Stop. Maybe send the parents to dinner and a movie, and clean the hell out of the house while they're gone? :dunno:

A hole in the manifold would constantly push out exhaust. Nothing to do with when it sparks. Pushing out exhaust is a good 4th of what your cylinder does, and there's always at least one piston doing it. Rockauto has a manifold for $70, or a $90 one that comes with 1 Manifold gasket, 2 studs, 2 nuts, 2 washers, 2 5/16inch Bolts, 2 5/16inch Lock Washers, 1 Oxygen Sensor Plug, 1 EGR Gasket, 1 Block-off Plate

Coming from the guy who won't stop telling me to get a GPS...

The one in my 88 XJ went bad from sitting. After a decent amount of searching, I found I was able to do a quick test with a multimeter. Set it to read ohms, and touch the positive to the positive post where the plug goes, and negative to the terminal for the plug wire. Should be less than 1 ohm. Mine was 13.

If you get the 4wd Trans, you MUST get a T-case to bolt to it, regardless of whether or not you're doing the full conversion. You cannot run a 4wd trans without the case.