rafiki Posted February 19, 2009 Share Posted February 19, 2009 Hello, This is my first post, i was wondering what will be the best way to fix a 1991 MJ 4.0 2WD, the engine is leaking everywhere, how hard is to rebuild the engine and how expensive or is possible to install and engine from a 2000 Grand cherokee 4.0L V6 4WD. Thank you for your help. Link to comment Share on other sites More sharing options...
BLHTAZ Posted February 19, 2009 Share Posted February 19, 2009 Welcome to the Club... :cheers: If you are mechanically inclined and you have a good selection of tools, you can do the engine work if you have a manual with the needed specs. I would not recommend trying it if you are not real comfortable with how an engine works and your ability to put it back together and make it work. If you have never done it, or seen it done, then you probably should find help. It should be no big deal to swap the GC engine in since you already have the HO version in yours. :thumbsup: This is the way I would go. Link to comment Share on other sites More sharing options...
87Warrior Posted February 19, 2009 Share Posted February 19, 2009 The 2000 GC 4.0 will pose a problem. It will have OBDII meaning: No distributor/coil/spark plug wires (has a camshaft position sensor in its place) and all of the sensors will be different. You can swap all that over from your 'bad' motor. The GC also had a slightly more aggressive cam than a TJ of the same year. Not sure how it compares to the MJ cam. You will also want the oil filter adapter off of your bad engine. Rebuilding the 4.0 is a piece of cake. It is constructed like any small block chevy. Just makes sure you have a quality machine shop do the machine work. I used the local classic race car engine builder do my machine work. If you are going with the trouble, pick up a 258 crank and make it a stroker.... I certainly wish I would have! Link to comment Share on other sites More sharing options...
wolfpackjeeper Posted February 19, 2009 Share Posted February 19, 2009 the 2000 engine will work fine, just use the block. I would consider keeping your head, use its intake manifold, your throttlebody and injectors. Yes it is set up for OBD2 and no dizzy ignition. But the hole for the dizzy is still there, it just has a cam sensor in it. Pull the sensor and slide in your dizzy. If you use your head you will be better off, the newer ones are prone to cracking. Clean it up and roll. Use a new set of good gaskets. I think you also will want to swap your t-stat housing over as well. If you use the newer intake, be sure to bring that PS setup over as well, then you can lookup the newer cherokee belt routing and run that, I like it better anyway. Save your timing cover as well as all the pieces inside, if you want to upgrade your cam later, your options are limited with that year, so you will want the pieces to be able to use the older style cam retaining setup. I tore through about 5 motors doing my stroker, and pieces of all made it into the build. None were the same year. Link to comment Share on other sites More sharing options...
codybutz Posted February 20, 2009 Share Posted February 20, 2009 not to high jack this thread but i am kinda in the same boat. i hav a 87 mj with the 4.0 that has 130k on it. i was thinking about a rebuild and if i should stroke it or not. its mostly a trail/camping/roadtrip truck. do you think the stroker kit would be a bad idea for this type of use? Link to comment Share on other sites More sharing options...
Pete M Posted February 20, 2009 Share Posted February 20, 2009 Is there something wrong with the engine? 130k is nothing for a 4.0. :D Link to comment Share on other sites More sharing options...
codybutz Posted February 20, 2009 Share Posted February 20, 2009 no it runs just leaks from all over and i plan on driving it across country this summer. i just didnt know the cons or the stroker or how its road manners where Link to comment Share on other sites More sharing options...
Pete M Posted February 20, 2009 Share Posted February 20, 2009 A better plan might be to replace the seals. You could end up spending a ton of money on a straight rebuild and not feel the difference. :dunno: If the truck feels sluggish with bigger tires, gearing would be the way I'd go about fixing that aspect. :thumbsup: Link to comment Share on other sites More sharing options...
codybutz Posted February 20, 2009 Share Posted February 20, 2009 i just figured since the truck is getting ripped apart and same with the engine to fix most the problems with that at once would it be worth the time to rebuild and or stroke it while i had it all apart? Link to comment Share on other sites More sharing options...
Pete M Posted February 20, 2009 Share Posted February 20, 2009 If more info was discovered during the tear-down, maybe. Depends on how scored the cylinder walls are. But if nothing is wrong, I personally would throw on a new timing chain set and seals and call it good. :thumbsup: Others may have different opinions. Would you be doing the work yourself? Everything I'd be doing would be done with the engine still in the truck. Link to comment Share on other sites More sharing options...
codybutz Posted February 20, 2009 Share Posted February 20, 2009 i could do the gaskets and smaller stuff but if i were gunna completely rebuild and stroke it i have somebody for that, that kinda owes me a favor. so if not a complete rebuild what would you do for starters? Link to comment Share on other sites More sharing options...
BLHTAZ Posted February 20, 2009 Share Posted February 20, 2009 If it's only leaking, you can probably fix that with a valve cover gasket, oil filter adapter o-rings, rear main seal, oil pan gasket, timing cover gasket and front crank seal. Definitely no need for a complete rebuild at only 130K unless, as Pete said, there is something known to be wrong internally. May be throw a fresh set of rod & main bearing in there while it's apart. Link to comment Share on other sites More sharing options...
Pete M Posted February 21, 2009 Share Posted February 21, 2009 i'd start by figuring out where it's leaking. :thumbsup: Or you can throw the book at it with BLHTAZ's list. :D Link to comment Share on other sites More sharing options...
aemsee Posted February 21, 2009 Share Posted February 21, 2009 If it's only leaking, you can probably fix that with a valve cover gasket, oil filter adapter o-rings, rear main seal, oil pan gasket, timing cover gasket and front crank seal. Definitely no need for a complete rebuild at only 130K unless, as Pete said, there is something known to be wrong internally. May be throw a fresh set of rod & main bearing in there while it's apart. Don't forget the CCV orifice grommet. That is probably plugged and the main reason for the MJ ebola. It only takes about 3psi crank crank case pressure to start seals leaking. Link to comment Share on other sites More sharing options...
Eagle Posted February 21, 2009 Share Posted February 21, 2009 no it runs just leaks from all over and i plan on driving it across country this summer. i just didnt know the cons or the stroker or how its road manners where About four years ago, an ex-girlfriend in Montana was looking for a Cherokee and couldn-t find anything in her price range out there. I found her a 1988 Cherokee Laredo here in CT with 165,000 miles on it that needed a flex plate. Put that in it, added an AAL to correct sagging rear springs, and drove it across the country to her. Ran fine, got about 22 MPG for the trip. The extended highway trip blew the rear main seal, so we had her local mechanic replace that when I got there, and the Jeep lasted her for several years until she decided to sell it and her car and buy a new Honda. (Bad choice - the Honda blew its engine within 6 months.) 135,000 for a 4.0L is barely broken in. Get the rear main seal replaced, and keep on truckin'. The stroker idea sounds attractive, but there are compromises involved and it isn't something to dive into without doing your homework. Aside from the issues with getting a stroker to run without ping, from all I have heard from people who have them, the fuel mileage is worse than a standard 4.0L. That, for me, was the end of my consideration. I don't NEED the extra torque enough to knock my fuel mileage below where it is now. Link to comment Share on other sites More sharing options...
wolfpackjeeper Posted February 21, 2009 Share Posted February 21, 2009 my stroker picked up mileage. went from an average of 15mpg to 18mpg. That is turning 33's on 3.55 gears. It should at the very least increase in town mileage. Of the several other people I know who have built one only one is getting no mileage gains. With the increase in torque and the same weight, plus you are generally moving the torqueband down; it should pick up a few MPG at the least every time. Link to comment Share on other sites More sharing options...
Eagle Posted February 21, 2009 Share Posted February 21, 2009 my stroker picked up mileage. went from an average of 15mpg to 18mpg. That is turning 33's on 3.55 gears. It should at the very least increase in town mileage. Of the several other people I know who have built one only one is getting no mileage gains. With the increase in torque and the same weight, plus you are generally moving the torqueband down; it should pick up a few MPG at the least every time. I always figured it should increase the mileage, too, but one of the compromises is the need to run bigger injectors to compensate for the higher compression. Link to comment Share on other sites More sharing options...
codybutz Posted February 22, 2009 Share Posted February 22, 2009 thanx guys, even tho i kinda hi jacked this thread youv'e answered alot of questions. i'm gunna start looking at that list of seals and then hopefully after she ( ya my mj is a girl) stops leaking, i'll be allowed to park her back in the driveway haha. Link to comment Share on other sites More sharing options...
rafiki Posted February 23, 2009 Author Share Posted February 23, 2009 Thank you guys, i think since my engine is leaking really bad i will wait for the rebuild or the swap i just going to get a new set of seals and replace them. Do you know of a good book that kind of guide how to do it? Also do you know if there is a Jeep club in Atlanta Georgia. Thank for your help. Rafiki Link to comment Share on other sites More sharing options...
Wildman Posted February 23, 2009 Share Posted February 23, 2009 The FSM is about the best "Book" you can get......not just for replacing the seals and gaskets, but for everything. This site has alot of info on gasket and seal replacements.......with color pictures too :D http://gojeep.willyshotrod.com/index.htm And scroll down about 3/4 of the page and you'll find = Service and repair items Also http://www.lunghd.com/ Has metric tons of info :ack: After you go thru and replace all the 20 year old seals and gaskets, I think you'll get a better feel on how un-destructive the 4.0 really is, oh, and repair some of the ccv system, these engines don't need a rebuilt every 80K :brows: Link to comment Share on other sites More sharing options...
dasbulliwagen Posted February 23, 2009 Share Posted February 23, 2009 You can go to autozone.com and purchase an alldata subscription specifically for your vehicle for about $20. It is all the factory service manuals copied onto one website. It is a great resource for shops that work on multiple makes of vehicles...allthough the subscriptions shops get will give you all vehicles down to a certain year and cost a lot more. If you are going to do a lot of work yourself on a vehicle, the $20 is really worth it. :thumbsup: Link to comment Share on other sites More sharing options...
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