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-   -   2.5 to 4.3 Swap (http://www.wranglerforum.com/f282/2-5-to-4-3-swap-124041.html)

unfundedtimmy 11-23-2011 12:27 AM

2.5 to 4.3 Swap
 
I've been debating on a few engines to swap in. I really wanted a diesel (for mileage and "coolness" factor). Was thinking 1.9 TDI but that quickly rose to $7k. I might look at 4bt but we'll see. So diesel looks to be out. Then I was thinking a 4.3 vortec. My uncle might get rid of his 1995 GMC jimmy (has transmission issues). The engine needs a rebuild but only to get it running well. There are no mechanical issues that I'm aware of. So I might buy the jimmy as a donor car. He might just give it to me too. Anyways I crunched the numbers and ended up with $2700-3000. That includes the jimmy, the NV3550 transmission, rebuild kit, transmission adapter kit. I still need to add the upgraded fuel pump into the total. I plan on using both the 2.5 ECM and 4.3 ECM. I will also get the crank position emulator for the tach. My question is does this sound about right and is there anything I'm missing? It won't happen for awhile. I have to put away some money for college and the other parts. The only thing I could get soon would be the jimmy. Also any suggestions for a way of doing it cheaper or ways you would do it are welcome! Thanks for your time.

TJspeed 11-23-2011 01:24 AM

Don't....... I had a 2000 blazer zr2 and I traded it in for my 2000 sport. The 4.0 is a waaaay better motor. And to me is a easier motor to work on. It's better built motor then the 4.3 and have you done the coolant conversion for the 4.3?

unfundedtimmy 11-23-2011 10:47 AM

Really? What would you suggest then? I talked about doing a 4.0 swap in an earlier thread and everyone told me that if I'm going to swap I might has well go big. I only picked the 4.3 because if all goes well, I'll have a whole vehicle to pull parts from for relatively cheap. I'll go through some other possible ideas but that's what is on the table right now.

TJspeed 11-24-2011 12:39 PM

I don't have any experience with motor swaps. But I'm assuming what they meant by "go big" was put a small block or a big block. And if you haven't done the coolant conversion on the 4.3 then you may have issues there. Idk just my 2 cents if I was gonna do a swap from a 2.5 to something else it would either be the bullet proof 4.0 or a small or big block.

unfundedtimmy 11-24-2011 02:07 PM

Ya I'm sure that's what they meant too. But this is what I have to work with. I'll look into a 4.0 and see how much that would add up too. I would like that one a lot as well. In fact, anything with more power than the 2.5 I'd be happy with. Around town is fine but freeway driving is just not enough. This won't happen Until this summer or so. That is when I'll actually have the time to do all this.

Hillbilly1 11-24-2011 06:50 PM

I'm doing the 4.3 swap later this winter. I have owned several 4.3's in several vehicles, they are a very durable motor, (200-300k miles) parts are much cheaper too because there a whole lot more 4.3's out there than the 4.0's I have a rolled S-10 Blazer that is the donor, it has a complete drive train that will bolt in the Jeep with a few modifications. (the biggest being the fuel pump and radiator) I have seen conversions using the S-10 radiator, but it is really too wide, and air flow is partially blocked. Motor mounts are readily available. I'm not at all impressed with Chrysler's motor and transmission durability.

unfundedtimmy 11-24-2011 09:18 PM

Ya I am thinking that is my best bet. According to novak-adapt.com I can keep my D35 and D30. I can also keep my transfer case as long as I get a 23 spline input adapter so that it will mate up with the AX-15 or NV3550. I'm not sure which to go with. Are they any advantages of going with the NV3550? Also, do you think I would be fine with keeping my D35 and D30 axles? Also I'm looking to get the 2 transmissions mentioned above because that would make for fewer modifications. I might be tempted to use the transmission in the jimmy but where it is having problems (pretty sure electrical), I probably won't. It is an auto anyways and I am like manual transmissions more.

@Hillbilly1
Are you going to do a write up on it?

jameslee97206 11-24-2011 09:26 PM

Here's a write up on it. 4.3 swap has finally begun - JeepForum.com The 4.3 is a good motor as stated above. Had a few of them myself.

unfundedtimmy 11-25-2011 12:25 PM

I looked at that. Looks really interesting. I'll have to read more on it later. Thanks!

Denalisdad 11-25-2011 08:58 PM

X3 on the 4.3 swap. Do your research. Compared to the 4.0, the 4.3's a much more durable engine, has a better torque/hp curve, plus the reliability is better than that of the 4.0. It's really a short version of a sbc. If a jeep already had a 4.0 I'd probably opt to keep it in place. If it's the 2.5 like mine, I'd definately opt for the 4.3 over the 4.0. Just a better design. Imho..

ou812 11-27-2011 03:39 AM

I had a 01 chevy 1500 ext cab 4.3 vortec,I put 171k miles on that truck.If you drove it with the 33's it felt like a v8 until you hit inclines at 80mph on the interstate or pulled a loaded trailer.That 4.3 used to roast those tires on burnouts.
Had an 81 elcamino with a 4.3,ran that engine hard for 5 years until we pulled a v8 swap,sold the engine running for $500

I have the 4.0 in my TJ,I would'nt swap from a 4.0 to a 4.3 but I would swap the 2.5 to a 4.3 anyday.Unless it was an offroad only toy,geared right the 2.4 kicks ass
my 2 cents

subtlez28 11-27-2011 07:43 AM

I hate to be "that guy", but couldn't you just sell your Jeep and use the extra $2700-3000 to buy a Jeep with a 4.0?

I think the 4.3 is a good engine, but never understood this swap. For all the hassle of a swap, why not go 5.3 or 5.7 LS1?

Hillbilly1 11-27-2011 09:51 AM

Quote:

Originally Posted by subtlez28 (Post 1775493)
I hate to be "that guy", but couldn't you just sell your Jeep and use the extra $2700-3000 to buy a Jeep with a 4.0?

I think the 4.3 is a good engine, but never understood this swap. For all the hassle of a swap, why not go 5.3 or 5.7 LS1?

Unless your going with some outragously big tires, the 4.3 is more than enough power for the light Jeep, and gets better fuel economy than than the 4.0, and with the bigger V-8's you start snapping things without really trying. If you already have the 4.0, then yes the cost of uprading would not be worth it.

unfundedtimmy 11-27-2011 02:14 PM

I don't want an outrageous amount of power. I'm going with the 4.3 because that is what I have to work with and from what I've heard it is better than the 4.0, is better on fuel, and is lighter. What would be the best transmission to put behind the 4.3. The AX-15, or the newer 5 speed that jeep had in the newer TJs? I would put the auto that the jimmy has in but it has problems. They can probably be fixed but I like having a standard.

Denalisdad 11-28-2011 10:36 AM

To me there's also the driveability part of the issue of selecting which engine to go with. I remember the older CJ5's with the V8's they came with at the time. It really didn't take much to spin one out on a wet road and wind up in an accident. For all-around driveability, not just going through mud or straight up a mountain, if you plan to use your jeep for daily transportation, the 4.3 would be a more 'user friendly' level of power and torque output than the 5.7 ( 350 ) in that size and weight of a vehicle.
Truth be known, that's probably why they didn't offer the chrysler 360 v8 in the wrangler. short wheelbase + light weight body + powerful V8 engine = something you and I can't afford to insure.
I've also looking at the possibiility of a 4.3 swap in my wrangler for a while now. However, I'm not in love with this particular one, so I'm also looking at selling this one and buying another with a 4.0. Not as good ( in my humble opinion ) as the 4.3 would be, but do I really want to start a project of this size on a vehicle I'm not absolutely in love with already? I need to be absolutely hell-bent on the swap before I pull the 2.5 out and kill a decent running jeep. Another thing to consider is, can I recoup my investment when I decide to sell the jeep with the 4.3 conversion, or even a 5.7 for that matter. I can see where there's no additional value to a jeep with a 4.0 conversion, other than the market price difference between the 2.5 and 4.0 that's already in place. I've found this to be a real can of worms. Lots to be considered with this..

unfundedtimmy 11-28-2011 11:23 AM

I did not think about the drivability aspect of it but I agree. I do not want in insane amount of horse power. And I plan on keeping this jeep for a long time. But around here, pretty much if it is a TJ and has a 4.0, you're looking at $8k. If it is a 2.5 TJ, $5k. I didn't have the money for a 4.0 but I still love my jeep. There isn't a lot wrong with it. The tub is in good shape (minus the windshield frame but not a big deal). The frame could use some work but it isn't a rust bucket and if I didn't have to drive it on the freeway so much I'd probably keep the 2.5 instead. Doing the conversion will allow a couple of things. I will have a nice fun project to do. It will allow me to clean up the frame a little. I am not a great mechanic but my brother and dad are so it will also give me a chance to learn a little more as well. There is a lot to consider but the $3k I'll put into it will be just like me selling my current jeep and then buying one with a 4.0. (assuming I get the same price that I bought it for). So going this route I get to keep the jeep that I know better and this way I know more or less what is wrong with it so I won't get any surprises like I would with a new one. I also like working with what I got and don't like to trade up and take the easy way out. Haha

subtlez28 11-28-2011 11:52 AM

Quote:

Originally Posted by Denalisdad (Post 1778785)
To me there's also the driveability part of the issue of selecting which engine to go with. I remember the older CJ5's with the V8's they came with at the time. It really didn't take much to spin one out on a wet road and wind up in an accident. For all-around driveability, not just going through mud or straight up a mountain, if you plan to use your jeep for daily transportation, the 4.3 would be a more 'user friendly' level of power and torque output than the 5.7 ( 350 ) in that size and weight of a vehicle.
Truth be known, that's probably why they didn't offer the chrysler 360 v8 in the wrangler. short wheelbase + light weight body + powerful V8 engine = something you and I can't afford to insure.
I've also looking at the possibiility of a 4.3 swap in my wrangler for a while now. However, I'm not in love with this particular one, so I'm also looking at selling this one and buying another with a 4.0. Not as good ( in my humble opinion ) as the 4.3 would be, but do I really want to start a project of this size on a vehicle I'm not absolutely in love with already? I need to be absolutely hell-bent on the swap before I pull the 2.5 out and kill a decent running jeep. Another thing to consider is, can I recoup my investment when I decide to sell the jeep with the 4.3 conversion, or even a 5.7 for that matter. I can see where there's no additional value to a jeep with a 4.0 conversion, other than the market price difference between the 2.5 and 4.0 that's already in place. I've found this to be a real can of worms. Lots to be considered with this..

I both agree and disagree with you Denalisdad. I agree recouping money spent on a swap is unlikely.

I disagree on the to much engine for the weight of the Jeep. I do not know what old CJs weigh, but was unpleasantly surprised at the weight of TJs. My Rubicon w gear and people in it weighs 4500 pounds!! So even empty we are talking 4000. That is light truck weight, I think a small V8 would be great to tow it around while in 2H.

That said, in 4L the TC makes for plenty of torque, so no need for an upgrade there. And, yes, a Jeep is no sports car. So speed combined with marginal brakes and so-so handling could spell disaster if you are getting crazy.

All that said, I still want a Hemi of LS1 swap...:D

jeepinmike 11-28-2011 01:56 PM

Quote:

Originally Posted by unfundedtimmy (Post 1776303)
I'm going with the 4.3 because that is what I have to work with.

Sometimes I think this is reason enough just to leave someone alone, and not bother them with other options or try to talk them out of it.

subtlez28 11-29-2011 08:43 AM

Just for the record, I am not trying to talk you out of it. The 4.3 is a good engine.

Just a discussion on why this is a common swap, I have seen a couple, and wondered.

unfundedtimmy 11-29-2011 09:48 AM

Oh I know. I am liking the discussion. I think if anything it's reinforced what I plan to do. The only problem I see is it is a 1995 engine whereas my jeep is a 1997. I'm registered in Idaho right now but plan to get residency in Utah sometime in the future. I've looked up on the Internet on what the engine swap laws were but I couldn't get a straight answer. Places I could live are weber, cache valley, and the salt lake city area. The only info I could find was the salt lake city laws and I couldn't figure out of they meant that the engine had to come from the same year or that an older swapped engine would have to pass emissions for the model year of the vehicle getting the swap. Anyone have any knowledge on this?

deathphoenix99 11-29-2011 01:46 PM

I can't help you with the legality side, but I can help you with the 4.3 side. That specific 4.3 is known as the CPI RPO L35, it was used from 92-95 with good results. It has about 195 HP and 260 Ft/lb's of torque. Fuel mileage is decent, and from my research, is just as good as the newer 4.3's if not a bit better. The intake on the CPI's is known for it's low end torque but not as much high end. The design is similiar to having a long tube intake, so it's good down low but lags up high.

As far as a computer goes, try to get one that is in the dash as it will be easier to work with, the underhood computers are more of a pain for the CPI.

Shortcomings: The only issues with the CPI is that their injector assemblies are known to have issues. The lines are plastic and the poppets can clog. However, most never have any issues and last at least 100K before giving issues. You can buy new ones for around $200-300 and that's for the whole assembly and should be trouble free for years to come.

I had a 95 blazer I ended up parting out, it had 260K on the engine and still had plenty of power to roast the tires, this included the white smoke trail I left behind since it had a bad headgasket. I've owned 3 4.3's and have never been disappointed. The 4.0 that's in the 2001 TJ, I can't say the same. I'm not sure if it's the 3-speed auto or not, but it's a slug. Not to mention I've had plenty of friends with wranglers/cherokees and my 4.3 has always won. Personally I'd take the 4.3 and the parts are dime a dozen. They've been in a lot of vehicles since 85 when it was introduced and are still in production in Full-size pickups with very little changes.

If you need any information, repair, wiring diagrams etc.....PM me and I can hook you up.

Denalisdad 11-30-2011 01:59 AM

Deathphoenix99, I think you brought some good info to the table. Sounds like you've worked on a few. Personally, I'm just partial to the previous 4.3, with the throttle body injection, over the multiport injection. I've had one of those in a truck I bought new almost 20 years ago, and it's still going strong. I've added a couple of performance goodies to it because that truck has towed some heavy loads. (we built a log home and it hauled 'em all with that 4.3 chevy six, just like the hemi trucks dodge is advertising right now on their latest tv commercial.) The latest 4.3 I have is in a 2006 silverado I also bought new, and has only 18k on the clock so far. Obviously I can't honestly speak for longevity on that one yet, but I will say that it doesn't feel like it has as much torque as the older one with the throttle body injection. Oddly enough, it also can't touch the 28 mpg I got with the older one. As a side note, 20 years ago, I also drove like I was - well, 20 years younger! As far as legalities go, many states won't allow an older engine swap in a conversion because of emissions laws. you can install an engine that's newer than the car, but not older from what I understand. You may want to go over to the 67-72chevytrucks.com website and do a few searches there. Some of the guys there have already crossed the emissions laws bridge on engine swaps and probably have it posted somewhere.

1SAS 11-30-2011 07:20 AM

I did a "frame up" restoration on my 1992 YJ. I swapped the four banger drivetrain with a Chevy 4.3 V6 and an AX15 transmission. You might want to check out what I had to do. If you already have a donor vehicle, 90% of your work is done. I can tell you that once you are finished, you will be pleased with the result. You have so much area under your hood for that V6. Take a look at the following "thread" and you will see what I mean.

Take care,

deathphoenix99 11-30-2011 07:33 AM

Quote:

Originally Posted by Denalisdad (Post 1784251)
Deathphoenix99, I think you brought some good info to the table. Sounds like you've worked on a few. Personally, I'm just partial to the previous 4.3, with the throttle body injection, over the multiport injection. I've had one of those in a truck I bought new almost 20 years ago, and it's still going strong. I've added a couple of performance goodies to it because that truck has towed some heavy loads. (we built a log home and it hauled 'em all with that 4.3 chevy six, just like the hemi trucks dodge is advertising right now on their latest tv commercial.) The latest 4.3 I have is in a 2006 silverado I also bought new, and has only 18k on the clock so far. Obviously I can't honestly speak for longevity on that one yet, but I will say that it doesn't feel like it has as much torque as the older one with the throttle body injection. Oddly enough, it also can't touch the 28 mpg I got with the older one. As a side note, 20 years ago, I also drove like I was - well, 20 years younger! As far as legalities go, many states won't allow an older engine swap in a conversion because of emissions laws. you can install an engine that's newer than the car, but not older from what I understand. You may want to go over to the 67-72chevytrucks.com website and do a few searches there. Some of the guys there have already crossed the emissions laws bridge on engine swaps and probably have it posted somewhere.

Drive a CPI and it has quite a bit more torque/power from the TBI's. The 96+ 4.3's still have a nice amount of power, but GM detuned them. You can either add a hotter cam (best method) and get a tune, or even a tune can help quite a bit. I know as years have progressed it seems that the power output feels less due to traction control, torque management etc.... I have a 2011 Silverado with the 4.3 and it has a nice amount of power, but unless I turn the Stabilitrack off, it's a noticeable difference. My dad has a 99 Silvy with the 4.3 and hasn't had to replace anything on it yet. Not to mention the other family members with the 4.3 in vans or Jimmys that have been untouched. I'm a moderator on a s10 forum so I definitely see my fair share of information on there.

OP: Here's some pics of what to expect, this was pulled from a 94 s10, 4x4. I only posted the links since I don't want to steal your thread.

http://i648.photobucket.com/albums/u...8/P3190155.jpg

And it is a bit long, just under 6' complete in the bed of my s10.
http://i648.photobucket.com/albums/u...8/P2270034.jpg

unfundedtimmy 11-30-2011 11:22 AM

I can get a donor jimmy that is the same year or newer if I have to. Or something else that has that engine in it. I will take a look at that site in a little while. My uncle may want to try to fix it so going to a newer motor may have to happen anyways. I'm excited to do this and by doing so, I will really make this jeep mine. Hopefully I can make this happen. Thanks for all the info. If there is anything else I should consider please post it. I'll probably go with the ax-15, use the t case I have with the spline adapter, keep my d30 and d35, and find a way to use both ECUs.

deathphoenix99 11-30-2011 12:08 PM

Why are you wanting to use both ECU's? It's probably possible to use just the swap ECU and have everything working. Just depends on what it's out of and year. All of the 96+ 4.3's are good, but something to consider, is that the 96-early 02's use poppets in the spider assembly which can cause issues in higher mileage. Well the new spider assembly has been updated in 02 and is fully backwards compatible in the 96+ 4.3's which moved the injectors down and eliminates the troublesome poppets. But that's normally only in high mileage or if the person had bad maintenance habits or ran crappy fuel etc... Also, 96 they redesigned the Heads to have better flow, although the earlier heads were fine for stock.

I personally love the 4.3 and it's probably one of the best gasoline 6's out there. It's a 350 missing cylinders 5 & 6 pretty much.

unfundedtimmy 11-30-2011 08:01 PM

I plan to use both ECUs because I thought that was the only way to get the gages working correcting. And my gauge cluster has a digital odometer. The jeep ECU keeps track of that correct? The jimmy one (1995) has an analog odometer so I don't believe the jimmy ECU keeps track of that... I might have to go with a newer model anyways because of Utah emission laws.. So I might be able to make a 1997+ jimmy ECU work with the gauges by themselves. Lots of stuff to consider really..

deathphoenix99 11-30-2011 08:11 PM

Well, all S-series keep the mileage stored in the cluster, not in the ECU. Although 98+ use a digital ODO. I'm not sure how Jeep does it, but in a Chevy, you swap out the cluster and the mileage on the new cluster will be showed, not what's on the ECU. I can look up some information about your cluster, just give me a day or so.

Hillbilly1 11-30-2011 08:19 PM

Quote:

Originally Posted by deathphoenix99 (Post 1785122)
Why are you wanting to use both ECU's? It's probably possible to use just the swap ECU and have everything working. Just depends on what it's out of and year. All of the 96+ 4.3's are good, but something to consider, is that the 96-early 02's use poppets in the spider assembly which can cause issues in higher mileage. Well the new spider assembly has been updated in 02 and is fully backwards compatible in the 96+ 4.3's which moved the injectors down and eliminates the troublesome poppets. But that's normally only in high mileage or if the person had bad maintenance habits or ran crappy fuel etc... Also, 96 they redesigned the Heads to have better flow, although the earlier heads were fine for stock.

I personally love the 4.3 and it's probably one of the best gasoline 6's out there. It's a 350 missing cylinders 5 & 6 pretty much.

Another issue with the older spiders is the high pressure fuel line rots out and leak under the intake. About $125 at the dealer. Replaced them (pressure and return comes as one assembly) on my daughters 95 S-10 blazer about a month ago. At 250,000 miles, it was probably due.

unfundedtimmy 11-30-2011 11:57 PM

Okay thanks deathphoenix. There is no rush. Like I said, won't happen for awhile.


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