4.0 head and EFI on a 4.2 block
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- Noob
- Posts: 14
- Joined: September 24th, 2011, 1:14 pm
- Stroker Displacement: 4.7
- Vehicle Year: 1974
- Vehicle Make: Internatio
- Vehicle Model: Scout
Re: 4.0 head and EFI on a 4.2 block
.030, .050 and .060. No Go.
I'm in the driveway, working on it as we speak!
Thanks,
Ray
I'm in the driveway, working on it as we speak!
Thanks,
Ray
- Jeep-Power
- Donator
- Posts: 184
- Joined: February 13th, 2008, 7:32 pm
- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
bummer.
Are you certain that you have the distributor correctly indexed?
Have you called HESCO?
Are you certain that you have the distributor correctly indexed?
Have you called HESCO?
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- Noob
- Posts: 14
- Joined: September 24th, 2011, 1:14 pm
- Stroker Displacement: 4.7
- Vehicle Year: 1974
- Vehicle Make: Internatio
- Vehicle Model: Scout
Re: 4.0 head and EFI on a 4.2 block
Yes, I've been on the phone with Bennie. We are not getting any spark out of the dizzy. I reindexed the dizzy, and cut off the ears to get everything fine tuned when we get it running. But first, I need to get spark!
I even reset the CPS to .030 per Bennie.
Thanks,
Ray
I even reset the CPS to .030 per Bennie.
Thanks,
Ray
- Jeep-Power
- Donator
- Posts: 184
- Joined: February 13th, 2008, 7:32 pm
- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
The coil - I know you said you have power to it. Is it good?
I don't have my FSM here at work...
I don't have my FSM here at work...
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- Noob
- Posts: 14
- Joined: September 24th, 2011, 1:14 pm
- Stroker Displacement: 4.7
- Vehicle Year: 1974
- Vehicle Make: Internatio
- Vehicle Model: Scout
Re: 4.0 head and EFI on a 4.2 block
It tested good, per the FSM specs.
Ray
Ray
- Jeep-Power
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- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
Ray-- how are you doin' with the Jeep?
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- Noob
- Posts: 14
- Joined: September 24th, 2011, 1:14 pm
- Stroker Displacement: 4.7
- Vehicle Year: 1974
- Vehicle Make: Internatio
- Vehicle Model: Scout
Re: 4.0 head and EFI on a 4.2 block
Peter,
I am doing good. The no start problem was a broken conductor in the cable that connected to the CPS. I metered everything out and replaced the cable.
I cranked the engine and it backfired out the TB so I knew I was out 180. Pulled the dizzy and reset it, and it fired up! This 258 MPFI runs awsome! I'm taking it over to the Pinelands for our "Scout the Pinelands" trip, next weekend. For now, I'm running local to get everything broke in.
And just a FYI, it is in a 1974 International Scout II.
I want to thank all who replied to my post for help.
Ray
I am doing good. The no start problem was a broken conductor in the cable that connected to the CPS. I metered everything out and replaced the cable.
I cranked the engine and it backfired out the TB so I knew I was out 180. Pulled the dizzy and reset it, and it fired up! This 258 MPFI runs awsome! I'm taking it over to the Pinelands for our "Scout the Pinelands" trip, next weekend. For now, I'm running local to get everything broke in.
And just a FYI, it is in a 1974 International Scout II.
![Stick :stick:](./images/smilies/prod.gif)
I want to thank all who replied to my post for help.
Ray
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- Jeep-Power
- Donator
- Posts: 184
- Joined: February 13th, 2008, 7:32 pm
- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
awesome.
Sorry about that-- I ASSumed...
enjoy!
Sorry about that-- I ASSumed...
![Mr. Green :mrgreen:](./images/smilies/icon_mrgreen.gif)
enjoy!
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- Posts: 5
- Joined: November 2nd, 2011, 4:12 am
- Vehicle Year: 1981
- Vehicle Make: Jeep
- Vehicle Model: CJ-8
Re: 4.0 head and EFI on a 4.2 block
"raises the compression ratio to something like 10:1. Higher compression means more throttle response and TORQU"
I've searched the forums and can't see where anyone needs to run higher octane gas because of the increased compression ration? I'd like to put a 4.0 head and fuel injection on my '81 scrambler, but I don't want to be stuck with real expensive gas.
I've searched the forums and can't see where anyone needs to run higher octane gas because of the increased compression ration? I'd like to put a 4.0 head and fuel injection on my '81 scrambler, but I don't want to be stuck with real expensive gas.
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- Posts: 3
- Joined: February 14th, 2012, 10:47 am
- Vehicle Year: 1982
- Vehicle Make: Jeep
- Vehicle Model: CJ5
Re: 4.0 head and EFI on a 4.2 block
New to the Jeep thing, can I use a 92-94 Jeep Grand Cherokee 4.0 4x4 as a donor for this conversion?
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- I made it to triple digits!
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- Vehicle Year: 1983
- Vehicle Make: Jeep
- Vehicle Model: Cherokee
Re: 4.0 head and EFI on a 4.2 block
yep, grab the fi also and enjoy
- Jeep-Power
- Donator
- Posts: 184
- Joined: February 13th, 2008, 7:32 pm
- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
Zorm wrote:yep, grab the fi also and enjoy
x2
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- I made it to triple digits!
- Posts: 151
- Joined: March 31st, 2008, 9:51 am
- Vehicle Year: 1983
- Vehicle Make: Jeep
- Vehicle Model: Cherokee
Re: 4.0 head and EFI on a 4.2 block
adding a 4.0 head to the 258 does not require the higher octane fuel. I had mine on for at least two years, not a tone of driving but I did drive it from San Diego to Pensacola, Fl with no issues and using reqular unleaded all the way. Now, I did not have the FI but I did have the 2100 carb, 258 intake and a HEI dizzy and loved the umph I got. Right now I'm building a 4.6 stroker with 30 over pistons, we'll see how the ole 83 Cherokee 4dr does with that.
- Jeep-Power
- Donator
- Posts: 184
- Joined: February 13th, 2008, 7:32 pm
- Stroker Displacement: 4.3
- Vehicle Year: 1984
- Vehicle Make: AMC/Jeep
- Vehicle Model: CJ-7
- Location: Fort Mill, SC
Re: 4.0 head and EFI on a 4.2 block
mine ran fine with 87, as well. Under heavy load (long interstate hills with the 34's on) the 92 octane made a noticeable difference. No pinging & more power. I'd just fill it with 92 before getting on the interstate. Otherwise, it was 87 around town.Zorm wrote:adding a 4.0 head to the 258 does not require the higher octane fuel. I had mine on for at least two years, not a tone of driving but I did drive it from San Diego to Pensacola, Fl with no issues and using reqular unleaded all the way. Now, I did not have the FI but I did have the 2100 carb, 258 intake and a HEI dizzy and loved the umph I got. Right now I'm building a 4.6 stroker with 30 over pistons, we'll see how the ole 83 Cherokee 4dr does with that.
good luck on the engine build!
-- TallPeter
'84 CJ-7 - tonned & turbo'd
'84 CJ-7 - tonned & turbo'd
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- Posts: 2
- Joined: February 27th, 2012, 8:24 pm
- Vehicle Year: 1983
- Vehicle Make: jeep
- Vehicle Model: cj5
Re: 4.0 head and EFI on a 4.2 block
Wow what a great article and some amazing contributors. Im fairly new to the jeep world. I bought an 83 cj5 with the 258. I dove in head first and put new axles under it (dana 60/44). I stretched the frame front and back and extended the wheelbase 19". 9 forward, and 10" back. Hummer wheels with 36X12.50. Now I've not got my new drivelines built yet BUT im anticipating some lack of power. The gear ratio was pretty well doubled but was a little doggy to begin with. I may still have to regear yet. The main reason for posting is I am planning on the 4.0 EFI head swap. It may be a while yet before I get the money scraped together to tackle the project. The previous owner had removed the factory "computer controlled" carb and replaced with a motorcraft carb which performed pretty reliably. Short story long, im concerned some of the wiring that was factory may have been removed. Maybe wrong but just wondering how to tell? Don't know what this thing looked like stock. Any thoughts, ideas will be greatly appreciated. Thank you everyone in advance. GREAT, GREAT article!
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