4.0 budget rebuild

[McSyd]

Hi all, new poster, long time reader.

I’m in the midst of a full blown CJ7 restoration. I was planning to build a stroker for this Jeep but both AMC 258 i6 / 4.2l cranks I had were no good. So for now, to keep my project moving, I decided on a bare bones 4.0 rebuild. All stock. No mods at all.

Ended up needing 30 over bore and a valve job. Block and head were cut a total of 0.007” I believe he said (mighta been 11). Otherwise everything is pretty basic. This is my first proper engine job. So I need a little help from those who have rebuilt a 4.0 or AMC 258 i6 / 4.2l .

My plans are to keep this as basic as possible. I ordered a 2150 carb and HEI dizzy from eBay. Planning to run the AMC 258 i6 / 4.2l intake on the 4.0 for simplicity. I’m going to save the original 4.0 intake in case I want fuel injection down the road. But in all likelihood I’ll end up doing a Chevy 350 down the road.

So a few questions:
Can I or should I reuse the original head bolts. I don’t believe they’re stretch bolts due to the torque specs. I’ve heard different opinions on reusing the old ones vs new. The machinist didn’t recommend arp bolts for this build due to the torque requirements

Is there a way to reuse the oil pickup for the oil pump? Or should I just get a new one? Any tricks to getting the tube installed without the fancy tool?

Any major negatives with using the AMC 258 i6 / 4.2l intake? I’m thinking for simplicity, to just use it instead of the 4.0 intake since I’m going carbed. I might do fuel injection down the rd but we’ll see. So I did t want to mess with plugging the injection ports on the 4.0 manifold and boogering it up in case I need it later.


Figured I’d get an HEI dizzy. Will I still need to stock AMC 258 i6 / 4.2l ignition control module? Or can I just skip that all together?

Will I need the stock ecm for anything? Plans are to make this as basic as basic can be. Carburetor, distributor, electric fuel pump. I can’t think of any reasons I’d need the ecm or ignition module with this setup. But I could be wrong. If I do t need the computer for anything I won’t have to do a nutter bypass correct?

What do I need for a water pump? I read somewhere about needing a reverse rotation pump for the 4.0 in a CJ7 . If so, which way is “reverse”? Clockwise or counter clockwise as you’re looking at the front from the radiator?

This motor was from an xj. Believe it’s a 1992 block. It originally had air conditioning. I’m not gonna need that. Can I simply omit that and get a stock serpentine belt for a 4.0 without ac? What about a belt tensioner? Not sure my motor had one when I got it.

One thing that’s bugging me. I have the short block assembled. I installed the timing set and on the crank there is an oil slinger. It has a key way in it but pushes past the key and just sort of floats there. That can’t be correct can it? Does anyone have a photo of how they sit on the crankshaft inside the timing cover?

I’ve included a few photos. I have 2 small core plugs leftover. They’re about 1” in diameter. Can’t find anywhere on the 4.0 for these but I see on the AMC 258 i6 / 4.2l block there’s holes that size. Are these just extras in the kit for a AMC 258 i6 / 4.2l rebuild or is there in fact a location for these on the AMC 258 i6 / 4.2l ?

 

[caveman]

I'll try to answer some of your questions. I have reused head bolts but wouldn't advise it on a new rebuild. They have been stretched and likely to fail in the near future. Buy a new oil pickup. It would be a real pain to have to find out it should have been done. You can reuse the AMC 258 i6 / 4.2l intake. If your head is the high port head it will take some finageling to get to fit right, but it has been done before. Many times. You can omit both the controll module and the ecm. All the ecm ever did was adjust the old carter carburetor and it did it poorly in my opinion. Water pump. I can't remember which way it turns. You can get a belt for the engine without the ac pump but you will need the ac pump delete pulley I believe. I've never seen one without.

Sent from my LG-LS777 using Tapatalk

 

[RiverandSand]

I will add if the engine ran a serpentine belt setup the water pump ran in reverse, if it was a v-belt system it ran in the other direction. So you will need the correct water pump to match belt system.

 

[mtnwhlr]

I will add if the engine ran a serpentine belt setup the water pump ran in reverse, if it was a v-belt system it ran in the other direction. So you will need the correct water pump to match belt system.

All 4.0 ran the serpentine belt.

 

[McSyd]

Thanks. I ended up getting a new oil pickup tube. I’m planning to use the CJ pan so I ordered a CJ tube. I’ll verify it’s the correct length when it comes.

I’ll order new head bolts

I ordered a reverse rotation water pump for a YJ. I think (hope) I read that’s what I need. If not I’ll return it for another one. It’s a 4.0 block with a serp belt.

I’ve seen I may have some issues with bracketry but somebody said in a forum somewhere that a ZJ setup works perfectly on a CJ7 swap. I’ll dig into that more later on.

 

[coldair]

I used all brackets off my California AMC 258 i6 / 4.2l ( serpentine setup ) the water pump also worked. I did have to cut the stock 4.0 intake. For the AMC 258 i6 / 4.2l intake you won’t have to cut it. I did have to move the AMC 258 i6 / 4.2l intake up to match the ports of the 4.0 head. If you have any more questions I’m more then happy to help out where I can.

 

[mtnwhlr]

.

I’ve seen I may have some issues with bracketry but somebody said in a forum somewhere that a ZJ setup works perfectly on a CJ7 swap. I’ll dig into that more later on.

So does the YJ setup.

 

[McSyd]

Got a little done today. Got the cam greased up and the oil pump and pickup installed. Got the oil pan on, lifters in then got the head and rockers on. Had to clean up the pushrods a bit before they went I .

Wasn’t sure where the 2 shorter head studs went. I had one in the front and one in the back corners. The front one interfered with the oil pan. So I moved it toward the middle. Hopefully it doesn’t matter because I don’t want to open it up again.

Had the same issue with bolts vs studs in the oil pan and valve cover. Not sure where the studs need to be. If anyone can advise I’d appreciate it.

I ordered a YJ/TJ water pump which looks like it’ll pump in the clockwise direction. So hopefully that’s correct.

Now it’s in to giving out what goes where for the accessories. That’s got me stressed for some reason. Having a bit of a time finding good assembly photos of the front of the 4.0. I also have 2 new “water pump studs” but not sure where those belong.

Hopefully this weekend I can get the engine installed in the frame and get the clutch in as well as the tcase and Transmission

 

[Belizean]

l like your 2x4 pretty well, but I have mine supported by a 2x8. A lot of weight hanging out there as you add more & more weight as the engine is built.

 

[McSyd]

Got the engine on the chassis today then moved the tub out of the way. I broke a motor mount bolt off in the block which kinda sucked. But I managed to fix it. It’s coming along. I’m trying to find out what goes in the threaded hole of the water pump. I circled it in yellow in the photo. I originally thought the temp sensor for the computer went there but that goes into the t state housing, so that’s not it. Also, will I need that temp sensor for the computer for any reason? I’m planning to use a MC 2150 carb on the AMC 258 i6 / 4.2l intake and completely do away with the computer. So can I just plug that and omit that front temp sensor?

 

[mriplaybass]

Looks like the heater hose nipple goes in there.

 

[McSyd]

Looks like the heater hose nipple goes in there.

Yep that’s what I needed. I managed to find an old one off an old water pump. I believe it’ll clean up well so I can reuse it. Thanks!