4.2 to 4.0 head/MPI is underway!

[Sasquach]

Started my project today, I had collected a #7120 head from clearwater with jackets welded, Ebayed a 4.0 cherokee exhaust header and alum. valve cover, went by napa for a new 4.0 head and manifold gasket and the big one I ordered the Mopar MPI system.
Started the tear down while I'm waiting for the mopar system figuring I can get the new head on and start the exhaust system while I wait.
It felt good to get the vac lines and old carb. off as well as the anchor they call an intake/exhaust manifold.
This was all gona be a winter project but I really could not wait.
Pics to follow as it goes back together...Yahooo

 

[BrockGrimes]

Sounds good, keep us posted, add lots of pic's.
Make note of any issues or unusual problems you encounter.
Hey you should weigh the parts removed compared to what you add.

 

[Sasquach]

Ran into my first unexpended glitch, You are supposed to be able to use your AMC 258 i6 / 4.2l head bolts in the 4.0 head (although new ones are recomended)not so in my case, the 4.0 uses shorter length bolts under the valve cover and the same length on the exposed ones.
Anyone see why I can't use grade 8 shouldered bolts from my local industrial bolt supply?


Did weigh a couple items for intrest,
AMC 258 i6 / 4.2l head with valves 71.5 lbs.
4.0 head with valves 68.5 lbs.
AMC 258 i6 / 4.2l exhaust and intake combined 48 lbs.
4.0 cherokee tubeular header 10 lbs.

Don't have the new alum. mpi intake yet but guessin' it's under 10 lbs?

 

[Sasquach]

Heres the head bolt situation and some shots of what I'm starting with.

 

[73CJ]

I got mine at cylinder head bolts, Engine hardware ,freeze plugs.

Check them out.

 

[ThisGuyUKnow]

I didnt have an issue with the bolts being different lengths. Are your cj bolts the smaller style or the half inch ones they use in the 4.0s. Mine were the smaller ones so I had to get the spacers from a company in CA. If yours are the thicker half inch bolts a trip to the pic n pull may be in order to find a 4.0 to steal them from.

 

[Sasquach]

I didnt have an issue with the bolts being different lengths. Are your cj bolts the smaller style or the half inch ones they use in the 4.0s. Mine were the smaller ones so I had to get the spacers from a company in CA. If yours are the thicker half inch bolts a trip to the pic n pull may be in order to find a 4.0 to steal them from.

The AMC 258 i6 / 4.2l 77-80 or there about has 1/2" bolts but 2 dif. lengths, as mne were. I used the link 73CJ provided and ordered a set for the 4.0, Pick N pull's don't exist where I live so that is not an option here.
Nothing is ever easy!
Thanks

 

[ThisGuyUKnow]

Too bad you dont have any pick n pulls near you because this would be an awesome time to swap in the serpentine set up.

 

[Sasquach]

why is there always something else to do? The serp crossed my mine but not gona go there....yet.

 

[ThisGuyUKnow]

well the serpentine swap is easy and I only had to slightly modify the AMC 258 i6 / 4.2l block in two places otherwise a bolt on affair. Definitely worth the effort. The biggest benefit being you will inherit the alternator used in the 4.0s which stock pump out about 40 amps more. i think the Xj ones put out over 100 amps and the zj ones put out 135 amps. So that should meet your power needs for the new MPFI components and the winch you have always wanted! The only bad thing I have found about it is that if you want to actually use the ac compressor for ac and not a place holder there may be some issues with mix n matching the newer compressor with the older CJ components. looks like you dont have ac though so guess that wouldn't be an issue... Could always turn it into an onboard air compressor for tires.

If you aren't going with the serp what are you doing about you PS reservoir? It may be different with the mopar conversion kit but when I did the MPFI the old PS pump wasn't going to mount to the new 4.0 intake so I had the option of converting everything to serpentine or swapping the pulley on the new ps pump to v belt pulley.

 

[Sasquach]

As far as the PS pump goes you do lose the mounting point at the manifold with the MPI manifold but it's still stout with the remaining 4 bolt locations, can't see how the serp or V belt would matter there.Does the 4.0 PS pump bracket mount up to the AMC 258 i6 / 4.2l ? sounds like it must for the complete serp swap out.
I guess I will have to keep on the lookout for a future conversion.

 

[ThisGuyUKnow]

As far as the PS pump goes you do lose the mounting point at the manifold with the MPI manifold but it's still stout with the remaining 4 bolt locations, can't see how the serp or V belt would matter there.Does the 4.0 PS pump bracket mount up to the 4.2? sounds like it must for the complete serp swap out.
I guess I will have to keep on the lookout for a future conversion.

On the 4.0 the ps stuff mounts to the intake. I guess since you got the mopar kit its different. If I didn't go serpentine I was going to have to use a 4.0 ps pump any how and just swap the vbelt pulley onto it.

If lack of pic in pulls is the problem for you there are two near me that I have been meaning to check out. I may be able to piece together a serp set up for you.

 

[Sasquach]

My guess is they left the mounting holes off the Mopar intake because it can be used on either a AMC 258 i6 / 4.2l head or 4.0 head and they would only line up correctly with one or the other?
I'm pretty much commited to the V belt arrangement because I have that balancer coming, I never plan on putting AC in either as that was one of the first things I pulled off the CJ when I bought it.
If you see something to good to pass up though let me know.Thanks

 

[ThisGuyUKnow]

My guess is they left the mounting holes off the Mopar intake because it can be used on either a 4.2 head or 4.0 head and they would only line up correctly with one or the other?
I'm pretty much commited to the V belt arrangement because I have that balancer coming, I never plan on putting AC in either as that was one of the first things I pulled off the CJ when I bought it.
If you see something to good to pass up though let me know.Thanks

hmm i can keep an eye out. Do you have anything specific you need? I forgot about the cps.... I figured the mopar kit would come with the harmonic balancer with the cps relocation kit? I know hesco has it in serp but if the parts are ordered the parts are ordered. I will stop trying to tell you what to do on your project

Let me know if you want me to look for anything.

 

[Sasquach]

Thanks for keep'n an eye on me, I appreciate the concern and ideas!

 

[ThisGuyUKnow]

Thanks for keep'n an eye on me, I appreciate the concern and ideas!

Just let me know if you need anything from a pic n pull. I junkyarded all my stuff and I still ended up spending a little close to 1500 on everything so I can't even imagine what your bill for this is at.

 

[Sasquach]

Made a little progress today, head bolts came in the mail so was able to get the head and valve train back together. While I was waiting for the bolts with the help of a 1/8" welding rod that I bent into the right shape I had the muffler shop bend me up a head pipe out of 2 1/2" into the cat and a short bend to turn out and down just pass the skid plate-hope it's not too loud. Still waiting on the Mopar system so back on hold for a while.

 

[Cheepjeep85]

i still say that is one of the cleanest jeeps i have ever seen. not even any grease/oil or nothing on the bellcrank.

 

[ThisGuyUKnow]

Y is your brake booster so funny lookin? That is a hella clean engine compartment. I tried to clean mine while I had the top end apart but I very quickly because frustrated and bored and gave up.

 

[Sasquach]

The booster is an aftermarket item and is a duel diaphram type so it's a bit longer than the factory one.
I've been trying to get the thing dirty and haven't washed it since I put it all back together, maybe with the new motor work I'll want to drive it more.