258 with a cracked block?

it still runs great but leaks water . what is the best engine swap? I still want to stay with a inline 6.

 

Why not stay with the 258?? They've been around for a loooong time!

 

I'm sure others more knowledgeable will chime in but I'll get you started.
The Jeep I6s are all the same basic block, 232 (3.8L), 258 (4.2L), & the now famous 4.0L that jeep put in everything. The 258 is is just a bored out version of the 232, as is the 4.0 . When Jeep made the 4.0 they just rebuild and re-engineered the older I6's, put Fuel Injection, better emissions, electronics, etc., and most important went up from the low 100's hp to about 190hp if I'm not mistaken.

So, I said that to say this, they will all pretty much drop in without too much trouble. I've always thought that if you were willing to do the work (install computer module, new pump, etc) the 4.0 would be a great swap, but it makes things more complicated. In the end, I would probably drop in a rebuilt 258, you can get them for a couple grand and its a good simple engine. So my .02, get a 258 I6. I'm sure someone here can give a good rec on where to get a good one from.
Good Luck.

 

If it were me I'd find a used running 258, all the better if you can see/hear it run before purchase. Should be able to get a good engine for under $300. If $2K is in your budget I'd buy a used engine in rebuildable condition for $175-$250 and have it rebuilt by your local shop. The 4.0 is a good engine if you don't mind some extra expense and more of a project.

Actually, I'd try to patch the leak first. If you can find the leak maybe try notching the crack a bit so it's a v-shaped trench. Drain the block. Notch it maybe 1/2 to 2/3 of the casting thickness so it's still a skinny crack at the bottom. A dremel tool will do this easily. Then clean it and dry it very well. Cram some JB Weld into the crevice and let it cure completely before refilling. Make sure you patch clear to the end of the crack and maybe a bit beyond just to be safe you've patched it all. It sounds like a crazy idea that shouldn't work but in many cases it works just fine. It's done all the time. I patched a pair of water cooled exh manifolds for an I/O boat engine and they never leaked again (wet sediment left in bottom of manifold froze and split the manifolds at the seams).

 

You can put some BarsLeaks or something similar in the radiator and it will stop the leak....at least for a while. It would give you the ability to drive it until you decide what to do as a permanent fix. Some shops can weld cracks in blocks, depending on the location. There is a welding rod made specifically for cast iron. I used it years ago on a IH tractor and worked fine. Just have to make sure that you preheat the area to be welded before welding.

 

I'm surprised nobody asked the obvious - Did you check the freeze plugs to see if thats where the leak is? simple to do and about $1 at your FLAPS.

 

If you can get to it I would weld that sucker over and keep on trucking . The rods are not that high . heat it up with a torch like dave said above and weld her up , then cover it to cool it as slow as posible . Ive welded STEERING components on 145 hp tractors and there are still holding today. I normally bury the part in the dirt after I weld it but that isnt going to work on a 258 R) R)

 

:iagree:
Pressure test the cooling system and you will find the leak.

 

What I did when my 76 engine began to show it's age, I found an 83, and I put my intake and exaust manifold on it. Works like a charm now


Bob

 

what about a 87 4.0 ? a local junkyard has one with everything on it for about 180.00 . what else do I need to make it work? anymore horsepower?if so what is the diffrence?

 

258s are cheap and available. If it's really cracked, find another one.

The 232 and 258 are the same bore but the 258 has a longer stroke. The 4.0L (242) has a shorter stroke than the 258 but a larger bore. These engines are so similar, you can put a 258 crank in a 242 block and get a 280 (4.6L) engine. The 4.0L is a great swap for the 258 if you keep the multiport fuel injection and can deal with the complexity of making it work in another chassis.