4.0 Head, MPFI, and Serpentine on my 82 258

[dalefan88]

good job man you just probally made half the people on here want to do that. just start it up and go. dam i can never do that even with my motorcraft carb.

 

[ThisGuyUKnow]

Well let's wait till I start it in below freezing weather. you can tell the engine is cold at stRt iup but it doesnt try to die on me when i give it gas. pretty sweet

 

[ThisGuyUKnow]

Just made the trek from Mobile Al to Macomb.

I had many problems, first I accidentally broke the return line on the ps pump trying to adjust out a belt squeak, then my headlamps fried on me, my rear diff started leaking, and my oil filter got a pinhole rupture some how and I literally pulled into my yard just as I completely lost oil pressure due to the level being so low.

The MPFI was true though. I have 2.73 gears with an ax15 and 31 inch tires so fifth gear is relatively useless and my shift points are weirdly spaced so I had some difficulty maintaining the speed I wanted(70-75 with a small trailer) but I was actually able to maintain it and pass if need be. Last time I drove the cj long distance I was lucky to get 65 in 4rth going down hill with no trailer. Now I can hit 80 no problem, 5th gear is a turd but again that is gearing. The MPFI made a huge difference I am going to try 3.54 gears and see how everything plays together

 

[ThisGuyUKnow]

how does it start cold? and hows the power?

congats to ya. I cant wait till I can get mine converted.

Still hasnt hit below freezing yet but its been getting pretty chilly (according to my Alabama standards) and so far no issues at all. Starts without having to tap the gas at all. In contrast my wagoneer which is still carb could not run worse. It seems that as soon as we made the shift from warm cool to cool cold weather the wagoneer has run like dog do which it normally runs smooth and good. Its also a huge PITA to get it to start and stay started and it definitely is very reluctant to move until it gets well above the blue.

 

[73CJ]

I did the 4.0 head 1200 miles ago. Love it. Running a Holley Projection FI. More more pumping the out of the pedal for cold starts. Hit the key -20F, fires right up. Why did I wait so long???

Nice post. Thanks

 

[ThisGuyUKnow]

Started and drove in 20 something degrees today

 

[ThisGuyUKnow]

After my dash switch for the headlamps burned out the other day, I replaced it with a new one. I have decided after posting in the chassis section I am going to run the headlamps through relays to reduce the amperage going to the switch and thereby increasing the amperage to the headlamps and hopefully avoid the sleeping on the side of the interstate at 4 am situation i had.

As fate would have it I have 3 relays left unused in the pdc so i am going to run the high/lowbeams/and foglights through those. I would have to run the headlight wiring through the passenger side of the front clip just to avoid excessively long wires.

 

[ThisGuyUKnow]

I had my first conversion related failure last week

Turns out I was very incorrect about my alternator bracket that used to hold the 4.0 alternator. The 4.0 has two holes drilled and tapped on the side of the block where the bracket bolts too. It also mounts to the timing cover with two other bolts. The two on the block are not there on AMC 258 i6 / 4.2l so I just used the two throw the timing cover.

This put the alty in the correct position and seemed sturdy but I drove 3 hours north of me the tuesday to pick up a 3.54 widetrac axle and on the way home about 140 miles away my alt output went out.

I limped it to the autozone and they put the tester on the bat and it said bad battery. So at 9 at night and in 25 degrees i bought a replacement and went to switching the alty. I removed the belt and when I grab the alt the whole assembly was wiggling like a loose tooth. The bolts had broken off. So I guess they were sufficient to hold the alt...

I am not ready to give up and go back to the Vbelt set up just yet. I am going to install it back the way it was but I am thinking about having some sort of brace or maybe even carefully measuring and trying to weld some heavy duty nuts to the side of the block in the same place the 4.0 block would have had them. just need to cut down on the vibration on the bracket.

 

[jmspreach]

You said earlier that you used a CPS out of an XJ? How were your able to mount it? I have a 78 CJ7 and would love to do this conversion, but the kits for CPS are a little steep right now. I have everything else out of 92 cherokee and if I could find a way to use that Crank Sensor, I may do this conversion real soon.

 

[ThisGuyUKnow]

You said earlier that you used a CPS out of an XJ? How were your able to mount it? I have a 78 CJ7 and would love to do this conversion, but the kits for CPS are a little steep right now. I have everything else out of 92 cherokee and if I could find a way to use that Crank Sensor, I may do this conversion real soon.

Unfortunately unless you want to swap to a 4.0 Transmission I don't know any way around that relocation kit. I have heard of people modifying their originally bellhousings to accept the cps. But I don't know anything about that.

 

[ThisGuyUKnow]

Ok so I think I have a workable solution to the alty issue. Apperently wranglers 91-95 used a two piece mount for the alty. The ac bracket in the wranglers looks almost identical to my xj one except it has an extra hole for the upper alty mount. Then it has a lower bracket that mounts in the same location as my xj bracket to recieve the lower alty mount. Since the upper is a 3 point mount just like the one I am currently running this should all bolt up in place of my current xj braketry.

I still will not be able to bolt the lower in the 2 rear holes like on a 4.0 but at lest now the lower bracket will not be supporting the weight of the alty with just two bolts. I am hoping the ac bracket will stabalize it enough to prevent future failure.

Will post pics when I get everything bolted up.

Big thanks to Ed(onlyinajeepcj) for the help with brainstorming a solution, I wasnt quite ready to give up on the serpentine and go back to v belt just yet.

Because I am desperate and in immediate need and just couldn't wait. I ended up paying a pretty overpriced penny for these on eBay but here are the brackets I bought.

Jeep Wrangler Alternator bracket. 91-99 TJ. YJ OEM - eBay (item 120651816978 end time Dec-07-10 19:12:01 PST)
the two holes on the top and bottom right facing the camera are for the two idler pulleys and the one on the left is for the upper alty mount

Lower bracket
Jeep Wrangler 4.0 Alternator Bracket 91-95 - eBay (item 330431036259 end time Jan-01-11 12:57:00 PST)

 

[ThisGuyUKnow]

The Cj is back on the Road. I used a tj upper alty bracket and a wrangler (not sure the year) Lower bracket. I need to get a tj 4.0 ps bracket because it has an idler pulley on it that adjusts the belt tension but for now it is working with the xj ps bracket. Hopefully with the two piece bracket enough stress will be movved off the two bolts on the lower bracket to prevent future failure.

 

[ThisGuyUKnow]

Turns out that after 96 they changed the PS pumps and brackets in the 4.0s so in order to run the 97 ps pump and bracket I had to swap out my 95 intake that was installed.

I took the opportunity to upgrade to the 01 "horse shoe" style intake that was in my basement. I got it cheap off someone who had dropped it and broke one of the ps mounts off so I had to have a welder fix it up.

Everything bolted up with ease. Turns out the new ps bracket has a strut that bolts to the side of the 4.0 block and as fate would have it the AMC 258 i6 / 4.2l has the same mount on the drivers side of the block. THat was a nice treat. I like the 96+ PS bracket way better than the 91-95 because now the ps pump is stationary and there is an idler pulley that adjusts up and down to tension the belt. In the 91-95 the ps pump moved to tension the belt.

Supposedly the 01 intake is the creme dela creme of the 4.0 intakes, or so the interweb rumors. I haven't yet plumbed my ps pump since i am doing a hydrobooster install in tandem with the intake swap so I haven't driven with the new intake yet. Keep your fingers crossed that the interweb is right and the new intake produces better power! I will report on that as soon as I can.

The only issue I have left is by the timing marks there is that weird sight thing that is for setting the timing without a timing light. It is suspiciously close to my belt and I am thinking about cutting it off since I don't know how to use it and I also no longer have to worry about setting the timing past TDC. Does anyone have a reason why that might be a bad idea before I go slicing and dicing?

 

[ThisGuyUKnow]

Pics of new intake

 

[ThisGuyUKnow]

The deed is done. I cut off that site post on the timing cover. Now I can get the belt pretty tight. No more squeals when I start up the CJ. I can definitely see a difference in the form of slightly higher voltage on the volt meter. Hopefully the alty bracket will hold this time around so I dont have to go changing things again.

As far as the horse shoe style intake goes. I didn't notice any diff in acceleration or anything. according to Jp they lost 5 hp when they bolted one of these to a 98 xj. Since my head is a 91-95 and higher flowing than an 96-99 head I dont think I would see a loss but I don't know if I really would expect a gain either. I read somewhere that the jeep engineers designed it because they needed a way to make up for HP loss due to programing and flow changes for emission in 99. SO they designed the intake to add 15 hp to the system. Either way it makes my bracket system work and doesn't seem to be hurting anything so whatever

 

[ThisGuyUKnow]

Here is some reading from JP on the horseshoe style intake and 4.0 heads.
They say they lost HP when bolting one onto a 98 xj. I don't feel much of a difference with mine I want to say its a tad easier to maintain 5th gear but that could be in my head.

 

[ThisGuyUKnow]

Here is some reading from JP on the horseshoe style intake and 4.0 heads.
They say they lost HP when bolting one onto a 98 xj. I don't feel much of a difference with mine I want to say its a tad easier to maintain 5th gear but that could be in my head.

I was looking back over the thread and saw I forgot to link the article I was referring to here
Jeep 4.0L Myth Busting True Lies - Jp Magazine

 

[Ironmerganser]

Got the clifford's spacers today.... for 33 dollars you get 4 spacers not 14. I called cliffords and was like "WTF" and they said that you just put two in the front and two in the back and thats all that is necessary.... I don't like it I think that it would make more sense to center all the bolts but whatever cliffords knows more about engines than I.

I used carbe cleaner to clean the mating surfaces of the block and the head and also cleaned the top of the pistons and the cyclinder walls. Then (since I have my Battery tray removed) I stood on the frame and dropped the head in placeTorqued the bolts all to 85 FT/LBs with the exception of #11 that got a little locktight on the thread and 75 Ft/LBS

.

So so you need these spacers? I have seen swaps with and without them?

 

[ThisGuyUKnow]

So so you need these spacers? I have seen swaps with and without them?

If you have any AMC 258 i6 / 4.2l that was made after jeep switched to the smaller headbolts then you woo need them

 

[Ironmerganser]

If you have any 258 that was made after jeep switched to the smaller headbolts then you woo need them

I have a 1979 CJ7 with what I think is the original AMC 258 i6 / 4.2l . I am assuming this means if I have the 1/2 inch head bolts I am good, but if I have the 7/16 inch head bolts I need to spacers. Correct?