Off Roading Forums banner
1 - 17 of 17 Posts
G

·
Discussion Starter · #1 ·
Okay, here's a question that I've been kicking around for a little while, but I figured I'd see if anyone else had thought or it, or maybe tried it. Since the Mopar EFI kit is essensially just oem parts from a '94 4.0L motor, and the part numbers and packing list is available on-line, as are complete directions, How hard would it be to put together a kit with all the same parts, using the 'junk yard' or a salvaged '94 YJ (or XJ for that matter)? I assume that there are some parts that are specific to the kit such as the speed sensor or maybe the balancer, but since we've got the part #'s, couldn't we order just those parts from the dealer? I'm asking this because I'm getting completely fed up with that stupid carb on my '90, but I'm short the $2,000+ for the Mopar kit. I don't want to go with an aftermarket kit, because in the past, I've ben burned by similar products which run and function fine, but when you break something, its a major ordeal to get replacesment parts. With factory parts, replacements are as close as a dealer, or a junk yard. Anyway, here's the real plan... I've seen several folks saying that a complete 4.0L with all the accy's, wiring and computer for under a grand. I could take the electronics, EFI system, and the 4.0 head! then maybe sell whats left (short block) for enough to buy beer for the friends I con into helping with the dirty work. That would give me not only the majority of the EFI kit, but the head for an even bigger boost in power and efficiency, for less that half of the price of the Mopar kit. Then, even if I had to buy several other parts to complete the kit, I'd still come out ahead, right? I'm hoping someone has done this and can let me know if it will work, and if so, what parts are needed to complete the kit, that won't already be on the salvage motor. Thanks all.

-Spyder
 
G

·
Discussion Starter · #2 ·
I think jo-jo has a friend that did what you are talking about, only he did it with a GM TBI which is what the Howell is. The only glitch
I can think of is making the computer think for a 258.

Brad (from the 4 Wheeling center of the universe, 4 corners USA)
 
G

·
Discussion Starter · #3 ·
Cheap(er) Mopar EFI - Tim, you out there?

Someone who has installed the Mopar kit, or at least have worked with them should be able to give me some idea... I hope. To try to make the question a little easier, shorter, and more to the point, If I buy a complete (including computer, wiring, etc) 4.0L from a '94 or '95 YJ and basically install it in my '90 YJ, except that I'd be substituting a 4.2L short block for the 4.0 one, what else would I need to make it work right? This should be the equivalent of installing a 4.0 head and Mopar EFI kit on my existing 4.2L. So, are there any parts that come with the Mopar conversion kit that aren't present on a stock '94 YJ? You know, stuff made specifically for the conversion kit to adapt the new EFI to the older motor? With all the knowledge in this forum, there's gotta be someone who has either done this, or a least thought about it. Help me out!! Thanks again.

-Spyder
 

·
Registered
Joined
·
1,025 Posts
Re: Cheap(er) Mopar EFI - Tim, you out there?

The only part that isn't avaliable is the bracket that mounts the crank angle sensor to the front lip of the oil pan. All the rest of the parts over the counter parts, and the harmonic balancer is a special order from Mopar Performance.

But if you mix and match 4.2 parts and 4.0 parts, why not just stroke the 4.0 with the 4.2's crank and rods. There is no replacement for displacement!
 
G

·
Discussion Starter · #5 ·
Re: Cheap(er) Mopar EFI - Tim, you out there?

Hey Spyder, I like your angle on this! I am thinking of droping a 4.0 into my 89 4.2 auto. but like your idea better. You get the best of both motors. If you use the 4.0 head and intake system on the 4.2, you would get the displacement and torgue of the 4.2 and the reliability and horsepower of the 4.0! Plus you wouldnt have the motor mounts and trans adapters to contend with. You would need a fuel tank with pump from a newer YJ, custom harness from someone like Hesco, damper kit ($170.) and the pickup( not sure where we could find that). Im sure there would be more to deal with but it would be on the minor side. You could even by a complete 4.0 package that had a bad motor for real cheap.Just make sure the head is O.K. Now I have a lot more to think of !!!!!!!
Later ........Herbie
 

·
Registered
Joined
·
1,025 Posts
Re: Cheap(er) Mopar EFI - Tim, you out there?

The motor mounts and transmission bolt pattern is the same on both the blocks. One bolt hole for the left motor mount has different threads, just use a fine thread bolt.
 
G

·
Discussion Starter · #7 ·
Re: Cheap(er) Mopar EFI - Tim, you out there?

You probably can get away from the Mopar kit's special dampner and sensor bracket because most of the manual trans (AX-15 & B/A 10-5) bellhousings I have seen have the mounting holes drilled in the top left area for the 4.0l factory sensor. Check yours to see if it is there. If so, the stock (manual trans type) sensor will fit right in and you won't need the kit part (which is a stock auto trans sensor). If you get the flywheel from the donor vehicle, it will fit the 4.2 perfectly. Most late 4.2l sixes have notches in them for the crank sensor but they will only work with the old 4.0l Renix system ('87-'90 XJ). If you are using a auto trans, get the '91 or newer type as it has the holes also. The 4.0l head has to be modified by blocking off the coolant passages on the drivers side, usually by welding & re-surfacing, because the 4.2 block has scalloped areas that will uncover the passages on the head. The 4.2 crank and rods work well but by using stock 4.0 pistons, you will wind up with around 10-1 or 10.5-1 compression. This won't work with pump gas and the performance computer timing. You may have to get custom pistons with more dish to get the compression down nearer to 9-1 to run pump gas again. Someone told me tha 307 chevy pistons may work, but I've never verified this. You also need to get a '91 YJ speed sensor so that you can still use your original cable driven speedo. The easiest way to go would be to just install the 4.0L and be done with it. This goes really easy if you switch out all of the wiring, guage clusters,dash,heater/vent system, etc. from a donor YJ, This approach works well in CJs if you don't mind the YJ style dash. Good luck!
 

·
Registered
Joined
·
111 Posts
I too have been kicking this idea around for some time. You could retrofit the 4.0 head and FI system to you 4.2, as I have thought of doing, but, in my case at least, I would need a rebuild of my 4.2 first. Think about the mileage already on your motor. At 130000 on mine, it still runs well, with good power, but it is definately tired. If you were to get a low mileage 4.0, for around a grand, taking in account for a quality rebuild, swaping the FI and head is as much as the Mopar kit. Of course, just buying the Mopar kit, the rebuild isn't addressed. My point, if you have a tired engine, and, you are poor like me, why not just swap the complete engine? you get a low mileage engine and FI in one step. Now if you need the extra power, do what it takes.

 

·
Registered
Joined
·
1,025 Posts
You are right, it is probably the most economicial. It shows by your profile that you have an '88, is that a standard, or automatic? The reason that I say this is only the '91 4.0 H.O. motors had the proper size pilot bearing for the tranny. These are unique. If it is an automatic, it shouldn't matter, except for the making sure that the new style flex plate would fit your torque converter. The flex plate is where the tone notches are for the crank angle sensor.

 

·
Registered
Joined
·
111 Posts
I've got an NV4500 in my YJ, so I'll need a new pilot bushing anway, but thanks for the info. Hopefully, I can get this swap done in the spring, I'll be happy to finally be rid of that damn bbd.

 
G

·
Discussion Starter · #11 ·
I examined this angle about a year and a half ago when I was on the Big Bear Jeep Jamboree along with one of the Jeep engineers. Here is the basic scoop.

You are correct in the fact that the Mopar kit is basically the FI setup off a 94. The differences are the harmonic balancer and the computer. The harmonic balancer problem can be fixed without too much problem, but you have to use the proper computer. The more difficult issue is smog legality. In CA (and comming soon to a state near you), you have to have a CARB (CA Air Resources Board) sticker on the vehicle covering the setup for it to pass smog. No CARB sticker, no smog sticker! In a nut shell, the 94 FI system will work, but u will never be able to make it legal...or at least in CA.

At $1700 for the setup, droping in a 94 or later engine with all the goodies might be cheaper...and at least legal...In CA you can always install a newer engine.

Good luck on this one............John

84CJ7
 

·
Registered
Joined
·
2,062 Posts
Now I'll grant that CA has it's problems with smog and, as much as we would like to think otherwise, the CARB is acting in an responsible manner in regards to pollution (at least they have good intentions) .... but wouldn't it be much wiser to have a "no harm - no foul" policy in regards to emission certification? That is, let anyone put any motor in any car as long as it passes the standard. The way I understand it ..... anything that you add to the motor must have that CARB cert on it. This eliminates the little guy from trying to build a better mouse trap (by little guy I mean anything from the back yard mechanic to the well equipt good sized speed shop) and leaves only the big guys, the ones with the resources to pay for the extensive testing, to reap the rewards. This has got to be the reason that TurboCity gets $70 for a piece of pipe. It would reason that if you have many people trying to achieve a given goal you'll have a much broader "genius base" to create these techniques/processes/devices. The current way adds much to the ultimate cost of the product. Point in question: We have to run an "Opacity" meter (reads the smoke) on our boilers because we run #5 fuel oil when natural gas is unavailable. The opactiy meter cost $2400 ...... except for the IDENTICAL meter that has the PENNA DER cert on it which costs $16000 ......simply because they had to get an underwritten performance certification for the approval.
I'm surprised that there isn't an organized lobby to change this to a more "inovative" approach.
If I was in CA I'd ask my representative if he drove a Jeep.......in fact why doesn't a Jeeper run for office under the "Anti-Smog Nazi" platform?

GeeAea

 

·
Registered
Joined
·
1,025 Posts
If you have the nv-4500, did you use the AA bell-housing, or the AA adapter plate to make it fit your 4.2? If you have the AA bell-housing, it should already have the crank angle bracket, and the stock 4.0 should be a direct bolt in.

 
G

·
Discussion Starter · #14 ·
Re: Cheap(er) Mopar EFI - Tim, you out there?

Enjoyed reading this discussion. Unfortunately, the head on my 4.2 '85, just crashed. One of the mounting posts for the rocker on the head busted off. So, I took my head gasket out and compared with the the head gasket on a 4.0 '87-95. All bolts line up, most water ports are very close. The bore on the 4.0 is greater than the 4.2. This idea of changing raises a couple of questions. Will a exhaust header system from a 4.2 head fit on the 4.0 head or does it require changing manifolds? What might be the problem using the larger bored head with the 4.2 bored .0060 over anyway. I think there is at least another .0060 - .0100 difference between the bores.
I did find a 95 4.0 Cherokee with 54,000 on it for $600.00, but I understand that I would need to change the 999 tranny, etc...Right? Thanks,
 
G

·
Discussion Starter · #15 ·
You bring up some very good points and for the most part I agree with you. In defense of CA smogs laws, this year we droped to the #2 position for smog behind Houston. What hurts LA is the ring of mountains around the basin to hold the smog in. Without that, the smog here would almost be non-existant. Basically, what this means is that the system works. The air is getting cleaner.

In regards to the smog equipment, I like to look at it as if it were software. Its easy to write a program that does all the basics, all the functions work, it runs fast, and looks good. But without some type of uniform and detailed testing, does it work the same way under all conditions and with all types of users? Tell me, who would you buy an OS from?...Micorsoft or Bill & Teds econo Windows? I know that this is a bit extreem but it kinda paints the picture of what CARB is up against. They need the uniform testing and standards to make sure that every TurboCity $70 pipe does what it says it will do. What we are really paying for is all the knuckleheads out there who try to sidestep the system....who really don't give a damn about others...just themselves.

Back to the original problem. You and I know that if we put the FI setup from a 94 on an older block...it works. We also know that if we replace the Carter BBD with a Webber it has lower emissions. We also know that if you properly maintain you engine, it will have lower emissions. However, CARB can't be an expert on every conbination, nor do they have the resources to test them all. It takes testing to prove that the Webber continues to meet spec over all RPM ranges and driving conditions and for the expected life of the carb. Hence, they keep the rules simple. You can't add it unless its CARB certified...or you can put in an engine from a newer car...with the logic that newer cars run cleaner...i.e., you can go forward, but not backwards.

Now, with all that said.....it is possible to make the Carter BBD work well if you can't aford the Mopar FI setup. It appears that adding the HEI dist helps a lot. It should be noted that when you add the FI you also replace the dist with one that is comparable to the GM HEI. With this in mind, the actual gain from FI may not be that great...or at least worth the money.

I'm sure that we will all hear more about this in the next few days.

Happy wheeling.........John

84CJ7
 
G

·
Discussion Starter · #16 ·
I've got 2 cents to add.

1) The Mopar EFI is CARB approve in CA. You get to CARB stickers with the KIt.

2) One of the biggest benefits of the Mopar EFI ins the increase Horsepower your going to get out of the 258.
It has been Dyno at 175 HP from 107 after the installation of the MPI. (4 Wheel Drive & Sport Utility - Sep. 97 pg 68)

3) Yes, it may cost more and $1700 is alot of money, but its been worthe every penny.
1 - Better Performance at a reasonable cost. $25 per additonal Horsepower. No other upgrade will provide you with
such a dramatic performance improvement.
2 - No more stalling for no reason. (You get rid of the Junk BBD and the poor computer control)
3 - Easy Starting
4 - Improved Mileage
5 - If you wife is drives it and it breaksdown in Kansas, A Chrylser Dealer can fix it
6 - Plus you keep the benefit of the torque of the 258 (256.8 ft-lbs with MPI Kit)
7 - You elimate the stalling problems you can encounter in Steep inclines
8 - You can install it, yourself in a weekend.
No scrounging around for all the parts.
Yes, building your own MPI, maybe a cheaper way to go and will work, but it takes alot time.
And finding Jeeps in Junkyards is better said than done.

OK, Yes the MPI Kit has problems too.
1- Pinging a problem for some early CJ's. I know that part of the problem in the poor flow that the 258 head has.
One resolution to consider is a 4.0L Head. Which has much better flow and does elimate the pinging problem.
I've never had the pinging problem, nor has anyone that I know that has the 4.0L Head.
2- We have a problem here in Colorado with Vapor Lock and the poor quality gas that we have to use.

What's your Jeep worth to you? For some it maybe better to go find a 91 or newer. For others they like the old CJ.
The Mopar MPI, I think is the best way to go, because of the additonal HP gain.
Howell and HEI would be my second choice. But, I don't think that you get the HP gain. Less Bucks, Less Bang
but a good system and it is also CARB approved.

My MPI Kit has been worth every penny of the upgrade. My 17 year old now drives it every day.

Tim Weaver
89 YJ 258MPI, 4.0L Head, Borla Headers, DynoMax Cat, Gibson CAT-Back.


 
G

·
Discussion Starter · #17 ·
Tim,
Your right on all accounts...however, I was mainly addressing the smog and CARB issues as related to trying to use the EFI setup from a 94. If I had the money right now, I would already have the Mopar unit. But being recently divorced (ex got the house, all I got was the bills and my jeep, meaning, I came out ahead)...the EFI will have to wait...

What I consider to be one of the more important issues is to make sure that the mod you make will be smog legal. If your state does not have smog controls yet, it will.

Summary of options....

1. If you have the money, go with the Mopar EFI.
2. Less money....drop in a 94 or later 4.0 with all the EFI attached...the smog issues will be easier.
3. GM HEI and keep the Carter
4. Webber...but for amost $400....I would save up for the EFI.

Anyone else have input?

John Gibson

ps...Tim, you let your 17 old drive your jeep?.....trusting aren't you.....my daughter wants one but she will have to buy it herself...

84CJ7
 
1 - 17 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top