2.5L to 4.0L Swap

[Mylesofsmyles]

I've done a few searches on this forum and on Cherokeeforum.com and google. does anyone have a good write-up on performing a 4-cyl to 6-cyl swap.

I have a 92 2 door with the 2.5l and a 5-speed manual with rear wheel drive. I can get a running 89 4 door with 4.0l and automatic with 4wd...thinking i'd swap the motor and, if possible, front axle and transfer case.

I understand it's a lot of work, which I'm up for...can this be done though without fabrication or modification? for the motor swap, is everything under the hood going to bolt/snap into place?

 

[joe_peters]

It can be done, going to take a bunch of work.

1. You are in CA, so you need to comply with their emissions laws, and that may prohibit using an earlier engine in your 92.

2. The 89 is Renix, your 92 is OBDI. Not only will you have to change over the engine management harness and computers from I4 to I6, but where would you access the harness and computers for an OBDI I6 from? You can't use the Renix stuff--CA laws and all.

Sell the 92 and 89, buy yourself a CA legal XJ with a I6 in it.

 

[96XJ_4.0]

Joe that one was mine! Hahaaa
I have the same answer. Sell ur rig and buy a 6cyl


Any swap should be a v8

 

[casm]

1. You are in CA, so you need to comply with their emissions laws, and that may prohibit using an earlier engine in your 92.

That alone will prohibit the swap. The emissions equipment on the engine you're swapping in must be both CARB-approved and not older than the model year of the vehicle it's being swapped into. Also, this swap will very likely involve a trip to the referee to confirm that it was done to CA's standards, so trying to slip it past them likely won't work unless you just flat-out never declare it. Which is fine, until you get to smog time, and the smog tech notices the two extra cylinders, and fails it.

So, long story short: like Joe recommended, sell the 4-cylinder and buy a 4.0. It's easier than dealing with the Smog Nazis.

 

[Jeff in VA]

I did the 2.5 to 4.0 swap in my MJ, but stayed with the same management system (renix). It literally was plug-and-play, and I didn't even swap the interior harness. The 4.0 engine harness plugged right into it with no problems.

As Joe said, you will need an OBD1 engine harness and ECU, and most likely would have to swap the interior harness as well (which is kind of a PITA because you need to pull the dash to do it).

Jeff

 

[casm]

As Joe said, you will need an OBD1 engine harness and ECU, and most likely would have to swap the interior harness as well (which is kind of a PITA because you need to pull the dash to do it).

True, but there's likely more to it than that in his case, though - remember that he has an '89 model year engine, but wants to put it in a '92 model year Jeep. California also considers the exhaust and intake to be emissions items, so those (at the least) would need to be updated as well. He'll also need an OBD1 computer and whatever else that may entail, since emissions controls need to match or exceed those specified for the year of manufacture.

I'm sure there are other things he'll need that I'm forgetting about; it's been a while since I dealt with California's idiocy in this department. But the way it usually works there after an engine swap is that you're sent to the referee, who inspects the vehicle to make sure it's a legal swap. If everything's not up to spec, the vehicle cannot be registered or legally operated on the street until such time as it is up to spec.

Note that I'm not arguing that what you're saying isn't correct - all I want is for the original poster to understand that because of where he lives there are certain legal practicalities he needs to be aware of before undertaking this venture. With what he has to work with in this case, it would be easy for him to end up in a situation whereby he does the conversion and then can't legally drive his vehicle on public roads.

 

[IslanderOffRoad]

The easiest way to do this:

Remove cigarette lighter
Replace Jeep
Reinstall cigarette lighter

 

[casm]

The easiest way to do this:

Remove cigarette lighter
Replace Jeep
Reinstall cigarette lighter

Exactly.

I'm kind of baffled as to why he wants to do this when he says the '89 is in running shape - maybe he just wants to stick with the 2-door bodystyle on the '92.

 

[Jeff in VA]

no worries casm, I was just pointing things out on the mechanical side of the swap. I've never lived anywhere that had emissions testing, and I for damn sure don't want to ever deal with anything related to California:roll:

Jeff

 

[96XJ_4.0]

FYI: I swapped a zetec focus motor into an escort. Focus stuff was all 2002, escort is a 99.

I have zero issues when smogging. Pipe sniffer, vin number...pass

 

[casm]

no worries casm, I was just pointing things out on the mechanical side of the swap. I've never lived anywhere that had emissions testing, and I for damn sure don't want to ever deal with anything related to California:roll:

Copy that After 10 years of dealing with the DMV and CARB there, I'm bloody well finished with them forever and damn glad for it, too.

FYI: I swapped a zetec focus motor into an escort. Focus stuff was all 2002, escort is a 99.

I have zero issues when smogging. Pipe sniffer, vin number...pass

Two things spring to mind here:

1) You put an engine from a newer vehicle into an older model. This is generally OK by CARB and the DMV; it's going the other way that it's a no-no.

2) Did you take the vehicle to a referee after the swap like you're supposed to? While I don't condone breaking the law, I personally don't care if you did or not - but if you take it for smog it can still be failed on a visual for non-approved equipment unless there's a referee's tag posted on the vehicle showing that the swap has been inspected and approved.

 

[96XJ_4.0]

Most smog guys can't tell the difference when a VCT is in place of an SPI... I havnt had an issue yet? Never knew about the referee.

IN FACT: I have no catalytic convertor and still pass! I don't like to brag about its setup but the vct dohc motor runs at 1/10 the emissions of the SPlit Port CVH motors. I did Cali a favor by doing the swap.

 

[soopergoober]

Where do you get your smog? I want a smog tech that doesn't even check for a cat!

Most smog guys can't tell the difference when a VCT is in place of an SPI... I havnt had an issue yet? Never knew about the referee.

IN FACT: I have no catalytic convertor and still pass! I don't like to brag about its setup but the vct dohc motor runs at 1/10 the emissions of the SPlit Port CVH motors. I did Cali a favor by doing the swap.

 

[96XJ_4.0]

Its lowered also, with obd2 o2 simulators, and yes PM me.