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Unread 07-24-2014, 02:12 PM   #1
JohnFM3
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A different approch to the 2.5 / 4.0 swap. Have an idea.

My sister recently received a family members 88 YJ. Partially due to the condition, mainly due to sentimental value, we have no interest in selling an getting a 4.0 version. Let alone, the frame an tub are in better shape that most non restored jeeps.

So what I understand we have. This is a 88 Jeep YJ, an if memory serves me correctly, running the Chevy 2.5L 4 cyl an fuel injection. An the power train is a BA-5 5sp with a 231 tcase an dana 30/35 which I confirmed are running 4.11 gears.

My thought is this, since the major issue of this swap is the fuel injection an the effort involved with swapping the harness, is it possible to maintain the factory harness?

So this is what I want to ask the forum. What if I perform the conversion with a 4.0L H.0. an instead us the Clifford Research (6=8) intake manifold meant to be used with a Chevy 350 throttle body (Howell injection conversion). To my knowledge, this would allow me to maintain the factory harness, an add the plug for the second injector in the TB (since they are batch fire anyways).

Yes I am aware of the changing of the motor mounts. I am not sure if the 4.0 will bolt up to the BA-5, I know that with me behind the wheel the BA-5 wont hold up. But this is my sister who for the time being wont be hard on it. Assuming the BA-5 can bolt to the 4.0L, when it does die a swap to a 92-95 5sp would be in order.

I also understand that the radiator is the same between the 2 engines, just change the hoses.

Anything else I need to think about, assuming the fuel injection thought is on track.

John

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Unread 07-24-2014, 03:10 PM   #2
The_Goob
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I cant vouch on the intake idea, sounds like an over-complication of things to me. As for the tranny, plan on replacing with an ax-15. I was unaware of a ba-5, I thought they all used Ba-10. it is regarded as one of the worst transmissions ever used, at least in a jeep.
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Unread 07-24-2014, 03:17 PM   #3
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Quote:
Originally Posted by The_Goob View Post
I cant vouch on the intake idea, sounds like an over-complication of things to me. As for the tranny, plan on replacing with an ax-15. I was unaware of a ba-5, I thought they all used Ba-10. it is regarded as one of the worst transmissions ever used, at least in a jeep.
Is it the BA-10? I will check that again. I can say its stock for a 2.5L. I do understand that its the worst of them.

Thanks
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Unread 07-24-2014, 03:27 PM   #4
The_Goob
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http://www.novak-adapt.com/knowledge/ba10_5.htm apparenty called BA10/5, same thing I guess
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Unread 07-24-2014, 03:32 PM   #5
JohnFM3
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Quote:
Originally Posted by The_Goob View Post
http://www.novak-adapt.com/knowledge/ba10_5.htm apparenty called BA10/5, same thing I guess
Hmm. Thanks. I know that I will need to pull it what ever it is. I have an 92 with the AX-15 an have been very pleased with it.
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Unread 07-24-2014, 09:01 PM   #6
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not that it matters since you plan on ripping them out anyway, but you have an AMC 2.5L and an AX-5 transmission...and no the transmission won't go behind a 4.0
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Unread 07-25-2014, 02:35 AM   #7
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If you're going to swap in the 4.0, all you do is add wiring for injector 5 & 6. There is a writeup around with pictures.

ECU for the 4.0
AX15
Wiring for the 2 additional injectors
weld in new motor mounts
*super brief version*
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Unread 07-25-2014, 05:07 AM   #8
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Wasnt there a couple years that the 4.0 came TBI like the early 2.5s? I assume that would be easier to wire up
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Unread 07-25-2014, 06:41 AM   #9
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Quote:
Originally Posted by mrdeath2000 View Post
If you're going to swap in the 4.0, all you do is add wiring for injector 5 & 6. There is a writeup around with pictures.

ECU for the 4.0
AX15
Wiring for the 2 additional injectors
weld in new motor mounts
*super brief version*
problem is the '87-'90 2.5L is TBI not Multiport...so there's only one injector

Quote:
Originally Posted by grandboost98 View Post
Wasnt there a couple years that the 4.0 came TBI like the early 2.5s? I assume that would be easier to wire up
not that I've ever seen..carbs on 4.2's and MPI on the 4.0L's
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Unread 07-25-2014, 10:12 AM   #10
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Quote:
Originally Posted by crackedcornish View Post
problem is the '87-'90 2.5L is TBI not Multiport...so there's only one injector



not that I've ever seen..carbs on 4.2's and MPI on the 4.0L's
Crackedconish: This is my thoughts as well.


To all, as CC stated, this is a TBI injected jeep. An in this case, it only has 1 injector which is why I will need to add a second injector for the Chevy TBI.

At this time, no one has said it wont work. I am really thinking I will move forward with it.
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Unread 07-25-2014, 10:14 AM   #11
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Quote:
Originally Posted by crackedcornish View Post
not that it matters since you plan on ripping them out anyway, but you have an AMC 2.5L and an AX-5 transmission...and no the transmission won't go behind a 4.0
Ok, so this means I need to change out the tranny at time of swap. Thanks.
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92 YJ (BOSS) 4.0L H.O. w/AX-15 5sp Manual, 231 TCase, Dana 30/8.8 (3.73) 2.5 inch Flowmaster R.E. 2 inch lift and 2 inch body lift for CJ clip
XJ http://www.cardomain.com/ride/2634588 YJ http://www.cardomain.com/ride/3322306
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Unread 07-25-2014, 10:36 AM   #12
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OP: What you propose could eventually work, but then what do you and your sister have? A "One-Off". Many members here have one-off items on their jeeps, and several have done engine and trans swaps, no there's nothing unusual there. My point is that when something goes wrong - its a YJ SOMETHING WILL GO WRONG - troubleshooting and diagnosing what is actually wrong will be a nightmare compared to buying a $800 used 4.o HO AX15 Cherokee and swapping over the engine, trans, ECU, and misc parts that will all be on the donor vehicle. If you have a problem, you are still dealing with basically either a stock cherokee drivetrain or a stock 88 Jeep chassis, frame and firewall back harness. It makes it a lot easier to keep it up and going. An added benefit is that parts are readily available in just about any city in north america - versus some cludged together aftermarket parts concoction of "mixed drink jungle juice".

I strongly advise you to either use the Jeep 4.0 HO engine and AX15 trans with factory jeep harness and ECU or go the Full Monty and start reading up on V8 swaps. Half-measures will leave you stranded and alone.

my 2

.
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Unread 07-25-2014, 12:12 PM   #13
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Quote:
Originally Posted by Luuca View Post
OP: What you propose could eventually work, but then what do you and your sister have? A "One-Off". Many members here have one-off items on their jeeps, and several have done engine and trans swaps, no there's nothing unusual there. My point is that when something goes wrong - its a YJ SOMETHING WILL GO WRONG - troubleshooting and diagnosing what is actually wrong will be a nightmare compared to buying a $800 used 4.o HO AX15 Cherokee and swapping over the engine, trans, ECU, and misc parts that will all be on the donor vehicle. If you have a problem, you are still dealing with basically either a stock cherokee drivetrain or a stock 88 Jeep chassis, frame and firewall back harness. It makes it a lot easier to keep it up and going. An added benefit is that parts are readily available in just about any city in north america - versus some cludged together aftermarket parts concoction of "mixed drink jungle juice".

I strongly advise you to either use the Jeep 4.0 HO engine and AX15 trans with factory jeep harness and ECU or go the Full Monty and start reading up on V8 swaps. Half-measures will leave you stranded and alone.

my 2

.
this x2!!

John, it says in your sig you already have 2 4.0L's, why not this one? do the swap with harness & ax15, no need to reinvent the fuel injection system - especially because it's 'not yours'. one thing I've learned, when doing something for someone else, do it awesome or they'll be back.

Goodluck!!
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Unread 07-25-2014, 03:08 PM   #14
crackedcornish
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Quote:
Originally Posted by JohnFM3 View Post
Ok, so this means I need to change out the tranny at time of swap. Thanks.
and you might want to just find a 231 with a 23 spline input gear already installed to match the ax-15...the 231's behind the ax-5 have 21 spline input gears
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