are all 4.0 block the same

[wjonthemove]

i have a 01 WJ.. 4x4 auto.. i found broken pieces in the oil pan. and need a rebuild.. are all the inline 6 4.0 blocks the same??? i need help. where would i find stock pistons and a master gasket kit.. this is my first jeep... need help..

[stamp]

91 and up i believe ...

[wjonthemove]

ok... nothing changed threw the years or added.. because im in need of a block and i have a 01 WJ 4x4.. there is a 96 at the junkyard. i dont wont to buy it and it be differend.. all sensors in the same place as all the other years???

[alwaysxj]

just from a plain 4.0 to the ho 4.0 and then in the xj 2000-2001 they did a way with the distributor.

[5-90]

1987-1990 had a boss drilled and tapped to accept the knock sensor (deleted for 1991,) and while 1991-2006 retained the boss, it went unmachined.

There may have been differences in the mount pads between the YJ/TJ and the XJ/MJ/ZJ/WJ, I've not yet confirmed this.

The 1999/2000 split (distributor ignition to COP/DIS) was a change in the cylinder head and had nothing to do with the block. This head may be retrofitted to any 242ci block, but the 1999-2001.5 heads should be avoided (apparently, the presence of a "TUPY" casting ID is a useful clue to avoiding membership in the "0331 Club" - but I don't know if that's 100%, either.)

The 242ci also saw the addition of a main cap brace for 1996 - this may be safely deleted (if you prefer,) or retrofitted to an earlier block (using the brace with associated main screws/studs and retaining nuts.)

There was some variation in cylinder wall thickness over the production life of the 242ci, as it got gradually lighter (eventually shedding a total of about 70-75#.) The earliest (1987-1988, AMC production RENIX) blocks are generally held to have the thickest walls going, and can usually support an overbore to 4.000" after ultrasonic inspection (that's boring an additional .125" - the typical max is .060" - and retaining a wall thickness of at least .100" all around, with any bias toward the major thrust side.)

It should be noted that any 242ci head will bolt to any 242ci block - but the head should be moved as part of a "top end assembly" when going back and forth across the 1990/1991 line (and note that the 0331 exhaust ports are smaller than the 0630 and 7120 ports.) The 242ci head will also swap onto the later (1975 or so on up) 258ci block, as I recall - make sure it uses head screws that are threaded 1/2"-13 (and not 7/16"-14.) NB: The manifolds will not swap between the 258ci and 242ci heads! The 0630 or 7120 head may be swapped in place of the 0331 head, while using the later exhaust manifold, if you fabricate an adapter plate to ensure sealing of the larger exhaust ports to the smaller manifold primaries (you can go the other way without incident - the 7120 and 0630 manifolds will bolt right up to the 0331 head without incident.)

All HO intakes will readily swap between HO heads, with later intakes being regarded as having better airflow (although you'll want to open up your exhaust to complement increased intake airflow.) There will be some accessory and bracketry changes needed to get the later intakes on the earlier engines (mostly the power steering pump.)

Anything else you'd like to know? I don't have Swappology anywhere near finished yet, so I've got to answer this stuff off the top of my head still...

[alwaysxj]

^^^^ their ya go.

[wjonthemove]

thanks for the info.. i just got this Wj and need to soak up as much info i can get.. thanks.

[Indian Outlaw]

I am in the middle of replacing the 4.0L in my 99 grand cherokee with a 4.0L out of a 99 cherokee and i noticed there is no a/c mounting bosses on the cherokee block. Is that the only difference and is there away to mount the a/c? Thanks

[jeepgod]

Not all 4.0 engines are the same even after 91 and up. You should be ok with the 99Cherokee to 99 Grand Cherokee swap though. Be careful, many people assume that they are the same but they are not. Suggestion: Next time call a junk yard to verify what year models for the 4.0 can be used in your vehicle. I know this as fact because I have talked with a few people around my area and they all had to find different engines and sell the ones they were going to swap.

[Indian Outlaw]

Originally Posted by jeepgod

Not all 4.0 engines are the same even after 91 and up. You should be ok with the 99Cherokee to 99 Grand Cherokee swap though. Be careful, many people assume that they are the same but they are not. Suggestion: Next time call a junk yard to verify what year models for the 4.0 can be used in your vehicle. I know this as fact because I have talked with a few people around my area and they all had to find different engines and sell the ones they were going to swap.

Thanks, the 99 G/cherokee 4.0L has bosses on the left front lower block to mount the a/c compressor plus it has the coil pak bolted to the cylinder head, the 99 cherokee has no bosses and has a distributor The junk yard said they where different but i was hoping you jeep guru's would know of a way around it.

[jeepgod]

If you want the right stuff, you need to find the right engine for it. There is no easy fix for your problem unless you get the right block for it. The only suggestion is to find another one and sell the one you have. Just a little fyi: the heads will swap but not the block.

[jeepride]

Since were talking 4.0 engine blocks my eng block does not the oil filter adapater that everyone has trouble with leaking o rings my oil fiter screws directly to block. It is a 99 xj I am guessing it is some kind of engine swap.

[Indian Outlaw]

Originally Posted by jeepgod

If you want the right stuff, you need to find the right engine for it. There is no easy fix for your problem unless you get the right block for it. The only suggestion is to find another one and sell the one you have. Just a little fyi: the heads will swap but not the block.

I am just amazed that jeep would have two different 4.0L in 1999. Also you can't swap the heads, the one is made to bolt on the coil pak

[jeepgod]

Originally Posted by Indian Outlaw

I am just amazed that jeep would have two different 4.0L in 1999. Also you can't swap the heads, the one is made to bolt on the coil pak

Crap, thats right, sorry for the brain fart. You can only swap the heads if they both have a distributor or if both do not have a distributor.

Yeah, that was the year they were transitioning to the new block that was distributorless and they were just using parts that were left over fromt he distributor ones until they basically ran out....that is what a friend of mine who works at the Chrystler test plant said.

[jeepgod]

Originally Posted by jeepride

Since were talking 4.0 engine blocks my eng block does not the oil filter adapater that everyone has trouble with leaking o rings my oil fiter screws directly to block. It is a 99 xj I am guessing it is some kind of engine swap.

Ummm, I do not remember that being changed as I have one on my 2001 XJ right now.....the G.C. I believe were the ones that did not have the oil adapters. They only used the adapters because of clearance issues in the XJ's. My engine is the original to the jeep by the way.