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1990 Isuzu Trooper V6
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Discussion Starter · #1 ·
I picked up a 1990 Trooper last August here locally in Salt Lake City. It's got the V6 2.8 and automatic transmission and 161K miles. The interior is in pretty good shape. I'm hoping to add a 2" lift, 31" tires, custom steel bumpers, roof rack and lights, colorado brakes, and of course the 3.4 v6 swap.
 

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3.4 from a 4Runner?
That would be a GM 3.4 Iron-Head V6 from a '93-'95 Camaro or Firebird. Another option is to stroke the 2.8 to a "3.2" which would be a bored-out 2.8 block (cleans up the worn-out bores), and installation of a 3.1/3100/3.4/3400 crankshaft and pistons meant for an iron-head 3.1 (such as a '91-'94 ZuZu 3.1 PU or a 1992 3.1 Camaro). Have the 2.8's rods reconditioned and a machine shop install the new pistons onto the rods. Voilà! You have a "3.2".

Anyway, just a short description, there are some nuances to the swap. I have info and can forward the files via email to interested parties. Start a private converstion, and send me your email address.

BTW the 4L30E is notorious for being weak, plugging-in a 3.4 and running taller tires won't help in that respect. Use synthetic trans oil and install an aftermarket cooler if you want it to live. And maybe a full service/adjustment wouldn't hurt, either.

If the trans has lots of miles and is tired, a performance rebuild is probably in order.

Here's a good 3.4 swap thread with tons of great info:


Cheers..............ed
 

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The 'Yota 3.4 would be a great engine in one of these, but a whole 'nother level of complications!
 

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1990 Isuzu Trooper V6
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Discussion Starter · #6 ·
Wood Engineering Machine Space Auto part


I ended up getting the motor pulled, now I need to swap everything over to the 3.4 and put that in, probably not as easy as it sounds
 

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Looks like fun! Now you have some swapping-over, and a few mods (like drilling for the driver's-side starter and cutting the block casting where it interferes with the oil filter adapter). It really isn't that much more involved than a simple R&R.

Be sure you check that 3.4 swap thread here that I posted, and my offer still stands for all the swap info I've collected over the years. My personal swap writeup alone will likely save you a lot of grief, not to mention the other info.

Good progress.............ed
 

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1990 Isuzu Trooper V6
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Discussion Starter · #9 ·
I'm finally back on this project, I'm looking for the bosses on the 3.4 that need to get buzzed off but I'm not sure I'm seeing them. Is it possible my 3.4 doesn't have them?
 

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There's one boss that may interfere with the 2.8 oil filter adapter. Test-fit with both the gauge sending unit and the pressure switch in place.

If you have the factory oil cooler, the lines may interfere with one of the unused motor mount bosses.

In that case, IIRC the solution was to cut the boss. Or, you could use a Canton Racing filter adapter which is smaller than stock and routes new hoses in a better place. Along with the Canton adapter you'll need to use a remote oil filter mount and also relocate the sending unit and pressure switch to the remote mount.

Geoffinbc has some good info about the Canton setup on his site:


An old post with more info:


HTH.............ed
 
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Discussion Starter · #12 ·
Also considering a swap to manual as an add on to this project. I'm showing that a 5 speed manual off of a 1998-2004 Rodeo will bolt up and work for the 3.4 V6, did I see somewhere that the MUA5 was also in some of the Isuzu Pickups? Does anyone know what years? I'm trying to look and see if there are any available in my area.
 

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98 Rodeo, 4JB1-TC
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Most manual Isuzu’s post 87 came with the MUA5, with the exception of some 2.6 Rodeos, and all 2.2 Rodeos Amigos and Rodeo Sports. That being said there are several configurations, so while the transmision itself may be the same, it will not necesarily bolt up.
 

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Also considering a swap to manual as an add on to this project. I'm showing that a 5 speed manual off of a 1998-2004 Rodeo will bolt up and work for the 3.4 V6, did I see somewhere that the MUA5 was also in some of the Isuzu Pickups? Does anyone know what years? I'm trying to look and see if there are any available in my area.
The 3.2 and 3.2 aluminum Isuzu V6's have a different (larger) bell housing pattern than the GM 60-deg V6. Where some confusion may have come from is that the ZuZu V6's are dual-drilled bolt patterns so they can also bolt up to a GM 4L30E automatic, which comes with a 60-deg GM V6 bolt pattern.

The larger bellhousing pattern is not compatible with the bolt pattern on the 60-deg GM V6 block. Unless you made some sort of adapter plate, I suppose.

You could swap cases but you'd have to have a MUA case for a 60-deg V6 already. So that's not much help!

Here's a list of MUA5 transmissions that will bolt right in with no mods:

'89-'91 2.8 Trooper
'91-'92 4WD Rodeo 3.1
'91-'94 ZuZu 4WD Pickup 3.1

If you had an '88-'91 Trooper 2.6 MUA5, you could swap cases with a 2.8 V6 trans as well. Still need a V6 case and BTW the bellhousing is NOT detachable on these. The entire front case of the transmission is what you'd be swapping. So unless you're really familiar with this trans, there's going to be a learning curve.

Differences between the 4-cyl/later ZuZu V6 trans, and the 2.8 trans, on the 4-cylinder the end of the trans output shaft is larger.

Resident Expert Jerry Lemond said you could bore out the V6's OE Oilite pilot bushing to fit the 4-cyl pilot shaft. Obviously you'd need a machinist for that.

Don't know about the later transmissions' input shafts, maybe they're larger too. At any rate, it's a mish-mash of parts.
Best if you can find a wrecked or rusty 2.8 or 3.1 MUA5. Try Craigslist, Offerup, Facebook Marketplace. Ain't like it used to be 20 years ago, stuff is just getting scarcer.

Good Luck...........ed
 
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www.car-part.com when inquiring for a 1990 ZuZu 2.8 Trooper manual trans, brings back around 20 results, scattered across the country. The lowest price listed was $300, and a bunch of them didn't list a price (you have to get hold of the yard for that).

Something else I didn't know existed, is a difference between having cruise control or not. Must be an extra switch or something like that for the cruise control circuit???? If you didn't have cruise on yours, I guess it wouldn't matter in any case.

Another search got tons of results for a '94 Pickup 3.1 4WD MUA5. Go figure! Didn't make any mention of cruise control, maybe the PU never came with that. Again, might not matter. You can always add an aftermarket cruise control system.

Anyway, there were a number of cheap ones available, including one for only $200 in a yard in Kentucky. I think the interchange book doesn't know what it's got, since this trans will go right in a Trooper. Maybe that's a good find, IDK.
 
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Discussion Starter · #17 ·
I'm making progress on this swap, would a video of drilling the starter mount holes be helpful?

What do you recommend using for boring the intake to 1-11/16"?
 

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Assuming you're talking about making a video of your own driling progress? I think that would be very helpful to other engine swappers.

Far as boring goes, I've done it twice; once on the vehicle, and once off. I made an aluminum spacer plate for the TBI unit, and that doubled as a template for the new holes, and a guide for the hole saw. Otherwise there's no way to do it at home unless you were to use a drill press and a boring bar.

Boring the holes with the hole saw is the "quick and dirty" way to do it. It does "get 'er dun" but it ain't pretty! You do have to be careful that you place the TBI mounting surface on the intake precisely at a right angle to the boring tool.

Since the manifold is sloped, you can't just level up the bottom of the intake and have at it. In other words the boring tool has to be aligned to the plane of the holes, not the base of the intake. There are water passages in the intake, and that's the reason for the 1-11/16" diameter. Any larger and you'd risk cutting into a water passage.

A boring bar or similar machinist's tools are gonna make a much cleaner and more accurate hole. If you have any good machine shops in the area, this job should be child's play for them.

After I sawed-out the holes, I cleaned them up with a round file and some sandpaper. A Dremel would probably do a good job, too. But you'll get better results at a machine shop, for a price.

Hope that helps..........ed
 
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