Motor swap

[377Z]

Swap a 1991 4.0 for a 2000 4.0? Differences?

I'm having trouble constraining a search in a way that will return the result I'm looking for. I have a 1991 Explorer 4.0/5spd and I may have an opportunity to purchase a 2000 Explorer 4.0 ohv motor. I know there are differences between the two, intakes are different and whatnot, but will it work? Specifically:

1. I would use my original wiring/computer, would I have to swap any sensors/electronics due to differences ( like, hypothetically, if a temp sensor ran on 7 volt signal instead of 5 or different resistance or something)

2. I would like to use the newer intake, but if I couldn't manage it, can I use my original 1991 intake on the 2000 engine (will it physically bolt up)? I know Ford changed some things on the inside, but can I just get away by swapping the longblocks?

3. If it won't work, please tell me why not. Knowledge is power.

My current engine has ~139K on it, runs great, and I'm shooting for 200K for starters, but I can always sock a newer 17K mile motor away in the garage if I can get it for $725 complete.

Thanks

 

[Alec]

I think some members have done it. However, you may have some problems with the computer programming in that the 2000 has a higher compression than the early model and the spark and fuel curves will most likely be different. You can probably get around this just by using an aftermarket chip that is custom programmed, maybe the Apten chip.

You should use the new intake and MAS, it will work, esp if you get that custom chip.

I think there are some misc sensors and stuff you'll need to mess with. 410fortune and Brett are the ones to talk to, they've done 4.0 swaps to their Bronco IIs and know a lot about them.

Oh, and about using the intake, you'd just need to figure out where to put the battery and fluid bottles.

 

[410Fortune]

It can be done, keeping your 91 upper intake and sensors. Or you can upgrade the entire trucks computer and wiring harness to the 2000 version (alot more work and $$$)

$725 is steep for a used 4.0L of any year, at least here in Denver.

Checkout Rangerpowersports.com and search the 4.0L boards..........

Your 91 uses a single 02 sensor and a MAP sensor, in 93 they swapped that for a different harness with dual 02's, no MAP, and a different computer....

 

[377Z]

Is $725 really expensive for a 3 year old motor with 17K miles? Its just that when I saw the cost of the rocker shaft assy & roller lifters I almost choked--they're closing in on the price above! I will check the ads on the board though--I don't need a motor yet but a spare is always good. I will look into the ads on the board though.

thank you

 

[Apten]

1. I would imagine you will have some problems with sensors, the 91's were managed quite differently than the 2000's. You could do it, but with a different intake the computer will be a little goofy. We could probably fix most of that with a chip.

The easier answer would be to use the 2000 harness, and a 96-1998 4.0L OHV computer. If you had the harness, I probably have a computer from those years that would work. I say 98 because that's the last year they didn't have PATS. After 98, you will need a pats transponder and a key programmer.

You will note that the later model explorers had the EEC in the engine bay. Take a close look at one and you will see how easy it would be to just use the 98 harness and computer.

Brian
bjherron@apten-us.com
http://www.apten-us.com

 

[377Z]

If I get this engine will try to use as many later parts as I can, though since the 2000 engine doesn't have a significantly higher power rating I won't be too concerned if I have to use the 1991 intake. My biggest concern is buying it and finding that it won't even bolt up! Its (unfortunately) not unheard of for manufacturers to move a bolt hole or change an angle or something ridiculus like that for no apparent reason, rendering certain swaps real difficult if not totally out of the question. It looks as though it will work, however.

From what I've seen, the factory cam timing is the same, compression is 9.7:1 in the newer motor vs. 9:1 in the older one. Since the power rating is still 160HP/225TQ with the same peaks, I have serious doubts that volumetric efficiency is out of the range of the 1991 computer to handle despite differences in intake, piston, and cylinder head port design; I'd bet it will still pass an IM240 with the original chip. If not, a custom chip would definitely cover it.

FYI I found this link again--it chronicles 4.0 differences throughout the years with respect to rebuilds. Who can I contact to recommend it for addition to the main page?

Dead Link Removed

 

[410Fortune]

For $725 I would get everything you will need, exhaust manifolds (just in case kinda stuff) sensors, wiring harness, computer, intake tube and airbox, etc....You never know what you are gonna need.

Basically its like this, you can either use the 2000 short block and heads, then use a chip to tune the timing and what not, or use the complete 2000 engine and change out the wiring as Brian states above......