I've been tossing around the idea of getting a used 94 4.0 engine from a recycler ($300.00) and rebuilding it while I continue to drive my truck then swap engines later. Would you be able to give me an idea of what it would cost to do a proper rebuild on one of these engines. I would be taking the heads to a machine shop for new giudes, seats, resurfacing, etc. What other parts would be advisable to replace? Anything else that I may not have considered? Thanks to all in advance!

 

It all depends on what you want to do. Since you are going to R&R the heads components you now will need to rering the engine thus when you disassemble you will need to mic the bores and possibly bore it out or at a minimum deglaze the cyls. Since you are now down to a bare block you may/maynot want to check the crank.

Cant give ya an prices as I have not been involved with one of these rebuilds in a while. Last one I did was on a motorcycle.

If you get an engine out of a wrecking yard, get one with as few miles as possible, clean up externally and just drop it in. I have almost 200K on my 94 now and have no engine work to speak of. plugs wires etc. Just put new water pump in because I had to R&R the radiator not because I had to but since I had the rad out.... You might want to redo the rear seal and the front timing seal prior to install but other than that you shouldnt need to do much unless you really want to. I would guess with purchase and all you will be looking at around $1000 again depending what you end up finding/doing and that just parts and probably machine shop time. this would not include an upgraded cam if there is even one available and it is stock head work nothing fancy.

 

You ought to go with new rocker arms and pushrods, too. Delta Cams has a kit for the 4.0L OHV:

http://www.deltacam.com/index.php (check out the bottom right-hand of the page)

 

What's wrong with your existing engine?? I've got 160,000 miles on my 4.0L and it runs like a top. Never opened it for anyting. Same valve cover and oil pan gaskets that Ford installed ack in 96. I did replace the rear main seal but only because I had the tranny out to replace the clutch. It wasn't leaking.

 

It kind of depends on what you want. You can do it all yourself, new bearings, rings, gaskets, and a valve job. These rebuilds seldom last more then 20-30 k miles before they are using oil if they don't blow up first. Or you can do it right with all the machine work, parts (crank,rods,pistons),gaskets and you will have quite a bit in it and it will last for 50-100k miles. The other choice is to get a remanfactured engine and get the 50-100k miles. It will be cheaper to buy the remanfacture engine because they get their parts for real wholesale and do the machine work in house. And they will give you a warrenty for 60-100K miles.

If you have the money to do it right and want the "fun" of doing the work and want to take the chance on providing you own warrenty. Go for it.

If you just want good rebuild buy a remanfactured with a good warrenty.

Dave

 

these 4.0 engines are pain. the heads are considered disposable. they are not machined. all the big rebuilders use new head castings. also most of the time these can't take a overbore so a liner is needed. you will be in at least 1500.00 in machine work. figure 600.00 for parts. then you must assemble it. a reman is only 1300.00

 

Thanks for all the replies! I really have'nt decided what I will be doing. I have done a complete rebuild on a different engine and had a good time doing it. The engine in the truck now has about 145,000 miles on it but seems to have no real power. The spark plugs are going to be a nightmare to get out as they are the original plugs, so can't do a compression check at this time. One already broke on removal. The hex part of the plug snapped off due to corrosion. Have not tried to get the others out yet. It is leaking oil from somewhere up high, probably the rocker covers and/or gasket. Have to put a quart of oil in about every 2 weeks but no noticable blue smoke and no large puddles on ground, and don't see any in the coolant.

 

Dude, I would spend a little time getting what you have strightened out. If those are the opriginal plugs, no wonder it soesn't ahve any power. FYI, my daughter's 2.3L Ranger went over 100K miles on the original plugs. The tips were burned off on most of them and it still ran but was starting to misfire.

Others may offer differing opinions, but my experience with the 4.0L V-6 has been very good and I've found it to be a pretty durable and reliable engine. I've had this engine in three four different vehicles and I've never had a serious problem. Two of those vehicles were company cars that I drove like I stole it. If what you have is not burning oil, I would not even think about opening it up.

Spend some time fixing the leaks and replace the plugs with Motorcraft (don't use Bosch - folks have had problems with them). If these are the original plugs and you got 145K miles out of them, why take a chance messing with a different brand. I realize they can be a pain in the **** to get at and remove but you may find it cures a bunch of your problems. I'd throw in a "good" set of new plug wires as well. Don't buy cheap.

Your oil leak could be something as simple as a cracked sensor of some sort that may also be contributing to the poor performance.

Again, no water in the oil, no oil in the water, and no smoke in the exhaust would equal no rebuild to me. LEt us know what you decide to do.

 

Thanks Texan, I live in **** deep snowy New Hampshire so I will start digging in to it the moment the weather breaks. I NEED that 4WD for the snow days and don't want to disable the truck in winter. My other truck is a 2WD 89 f150 and it don't do too good if it gets slick. I plan to try and remove the plugs and then check compression. I'd love to tear it apart and rebuild but it might be out of the budget right now. Thanks again.

 

If it's not smoking, I suspect your compression will be just fine.

FYI - we had snow here once. That stuff is cold.

72*F and sunny in Houston

Carl

 

The snow ain't cold. Outside, 20 below zero, 30 - 40 mph wind for 9 hours working on an airplane......NOW THATS COLDDDDDD !!