• DCRC 2024

4.0 head on a 4.2 engine?

gijohn40

gijohn40

too poor to wheel... :(
Location
Layton, Utah
ok I did a search for anything on this subject and nothing came back... so I'm throwing it out there... has anyone done a conversion on their old 4.2 engine to swap a EFI head onto their old block? If anyone has any material about this I would be glad to see it!!
John
 
I Lean

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
gijohn40 said:
ok I did a search for anything on this subject and nothing came back... so I'm throwing it out there... has anyone done a conversion on their old 4.2 engine to swap a EFI head onto their old block? If anyone has any material about this I would be glad to see it!!
John
Click to expand...

Creighton (Maxxis Pimp) has done it--I don't know the details, but I know it was a LOT of work, involved either drilling/tapping new holes in the block, or maybe in the head. It also involved grinding through a water jacket then having to patch that hole back up.

Ran pretty good when he was done though....
 
I Lean

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
Tacoma said:
http://monsterslayer.com/jeep/40Head/40Head.htm Google is your friend.

Seems to be a pretty concise explanation of what needs to be done, and doesn't seem like THAT much work. Nothing about grinding the head???
Click to expand...

From that article, I'm guessing this was the problem...not a grinding issue at all.

that article said:
Important!
Check for head overlap and water jacket exposure at the block-to head surface on the manifold side.
There are twelve triangular shaped water jacket holes all along the manifold side of the head.
Both Hesco and Clifford Performance welds these areas on their 4.0 head conversion kits.
Check the head against your block for head overlap and water jacket exposure, especially around the side indents.
Weld, epoxy, or freeze plug these offending areas for insurance against leaking. Many have no problems in this area. Others have reported water jacket exposure of as much as 1/16" on heads that overlap their blocks.
Click to expand...
 
R

RedBull_RockIt

Registered User
Devel said:
i beleave u also need to take the cam out of the 4.0 to make it work right
Click to expand...
no need to do that.

The conversion does take a bit of work but isn't really that difficult. It'll take the 4.0 computer and harness, everything on the head, the distributor, the harmonic with the magnetic pickup, and a high volume fuel pump. For the pump, many people use the E2000 but after we had our third one fail in three years, we jumped to the Edelbrock 3594 and no more failures. It was twice as expensive but lasted for years and is still working fine.

There's a few other things too, especially getting the head gasket right and filling one of the water jackets (or two, I forget) with epoxy. Also, I made my own alignment washers that go over the studs to be sure the head lines up right. I THINK Clifford sells them nowadays. It makes a BIG difference in the power and angles you can run. It was one of the first things I did to the old Red Bull Cj7 back in 2000 and was the best modification we did...beter than Dana 60s for sure.
 
rockreligious

rockreligious

NoEcoNaziAmmo
Location
Ephraim
There was a guy from Canada camped near us at Moab EJS who had done this, he JB welded the water Jackets, and built a custom harmo-balancer/flywheel strip for the magstrip(he owned a machine shop in canada) worked out nice a ran well. gained power and compression because the 4.0 head on the 4.2 is like shaving a head.

Seems like alot of work to me, thats why I just swaped 4.0, trans and all from a donor rig, but if you need the power and already have money dumped into a d20 or 300 might be worth doing.
 
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