FZJ80 V8 plus 5 spd conversion, with dual case?

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Mar 24, 2016
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San Angelo, Tx
disclaimer - i have read dozens and dozens of threads on these topics, but still havent quite found the answer. thanks to Beno, 70's guy, toolsrus, tor, romer, and many more for lots of ideas, info and knowledge.

BLUF: i am wanting to pursue a v8 conversion with 5 speed manual transmission, as well as a dual transfer case for my 1997 fzj80. the dual transfer case is the difficult part...

WANTS: Main reasons are to get around the usual 80 series weaknesses: power and range. I realize that for the cost of one of these conversions i could buy a small island (or a decent used 200 series and then a cheaper/beater dedicated crawler like a 1st gen 4runner), but i want to keep the 80 for the third row seating (i have a 3 kids and 1 more on the way), solid axles and lockers (we do some low risk crawling), but also be able to do some longer roadtrips. I have a 6" slee lift with 37s and (a 1" body lift that i plan to remove). i have 176,000 miles on the truck so far. it runs great, just sucks down the gas and i spend more time filling the gas tank than wheeling, all the while getting passed by Prius' towing tear drops....

EXPECTED RESULT: With the V8 I would be able to get 80 mph quickly and cruise there, while potentially getting much better fuel economy/range. With the manual tranny it would be more fun while driving, and with a dual case compensating for my lack of crawling ability with a stick shift, but also allowing a much more controlled, safer setup for technical wheeling with my family in the back of a massive whale of a cruiser. it would go from a 38.8:1 total gearing to somewhere close to 200:1. Ideally also an engine swap would make the setup closer to 'new vehicle' drive train reliability, rather than hoping my 1FZ-FE doesn't blow up (head gasket) on our next trip to the desert. And of course paying big money to a professional conversion shop allows them to do all the hard electrical work on harnesses, and making A/C, dash, buttons, equipment all still remain functional. SUMMARY: an 80 series with 200 series power and double the range.

PLANS:
a) already purchased, but still need to install: bigger fuel tank and marlin cruiser gear t-case gears. wont solve all the problems but it helps with range and gear ratios. I'll probably also be installing dynamatt to quiet things down a bit.

b) currently in the lead is sending the truck to dieseltoys in san antonio for them to swap in a import half cut 4.5L toyota D-4D twin turbo diesel v8 1VD-FTV engine, and a R150F transmission from a 70 series. hoping to also get a dual case/blackbox/Advanced adapter/marlin tacobox/etc, but i am not sure if it will all workout. The current plan would be to use the stock transfer case (HF2AV) to keep all wheel drive, ABS functionality, etc. Another option would be the 4.2L 1HD-FTE turbo diesel with H55F, also not sure about dual case. More power with the twin turbo V8. new overseas vehicle would hopefully mean better parts support than a 25 yr old 1HDT conversion.

c) backup expensive conversion plan would be to go to a different outfit (Proffitts, Torfab, TLC, etc) for a gas V8 swap, some sort of domestic 5 speed - maybe NV4500 or NV5600 6 speed, and hopefully some sort of dual case. Not sure exactly which parts and pieces. Domestic V8 would allow for even better parts availability, but might also require part time t-case, which causes ABS and AWD issues. i'd like to keep all wheel drive and ABS.

also, just for fun - i would also consider some sort of a hybrid family roll cage, and a 'spare wheel well area' storage box.

QUESTION:
does anyone know the details about how a 70 series engine and transmission could work out with the stock transfer case and a dual transfer case/box?

or a different transfer case? maybe from a VDJ79

howabout a 1HDTE 4.2L turbo diesel with H55F 5 spd and dual case?
 
Last edited:
Joined
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No help with the dual case requests but going diesel I don’t think you would need dual cases crawl ratios feel different with the amount of torque and self governing idle of the diesels. I wheeled a Jeep with a cummins 4.56 40” and a 50.1 crawl ratio and feel I could have done 4:10 gears. Pop the clutch and go like all the dual and triple cases r22’s out there.

Are your axle ratios I’m assuming you are already geared down so the diesel power sand might not be right and over Reving it without gearing changes.

Will be interesting to follow this one
 
Joined
Mar 24, 2016
Messages
19
Location
San Angelo, Tx
No help with the dual case requests but going diesel I don’t think you would need dual cases crawl ratios feel different with the amount of torque and self governing idle of the diesels. I wheeled a Jeep with a cummins 4.56 40” and a 50.1 crawl ratio and feel I could have done 4:10 gears. Pop the clutch and go like all the dual and triple cases r22’s out there.

Are your axle ratios I’m assuming you are already geared down so the diesel power sand might not be right and over Reving it without gearing changes.
good note about diesel torque being different. my 80 has 5.29 diff gearing, so with stock t-case gears at 2.488:1 and first gear at 2.95 my total low gear ratio is 38.8:1. with the marlin gears i will have 48.7:1. i think with as heavy as the vehicle is it would be much more controllable with a dual case
 
Joined
Jan 26, 2017
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Location
Portland, OR
I can't help you with stats or technical stuff, but I just clocked 18 MPG on a coastal roadtrip with my recently installed H55 pushed by the original 3FE. And I had fun shovelling the gears, so if you want it, keep at it. Good luck with your build.
 

Cruiserdrew

On the way there
SILVER Star
 
 
Joined
Mar 15, 2003
Messages
15,744
Location
Sacramento, CA
Sounds like it will be a very cool truck when done. Also sounds like you're working too hard to make it do what it can already do.

For more range-Long Ranger Tank from Cruiser Brothers
For more crawling-the Marlin gears are great (and sufficient to go anywhere in the USA)
For more power-Forget it
For more economy-Ride your bike to work

I would rethink the 80mph/6 inch lift/family-on-board thing. Huge top heavy truck is a rollover waiting to happen. And plus it's way over done. You can do hard trails like the Rubicon with a 4 inch lift.

My vote would be Chevy LS/NV4500/blackbox/Stock transfer. (though you might need a split case)-the parts for this already exist.

As sexy as a V8 twin turbo diesel sounds, no one in the US will know the motor or be able to get parts for it, at least not easily.

Now if you stay with an auto, you don't need gears that low. How about Chevy LS/autobox/Transfer with Marlin gears?

My real advice-drop the idea now. Buy a 200 for family duties and keep it stock, and build the 80 modestly for yourself on the side. You are not going to seriously wheel your 80 with 4 small children. Be honest with yourself.
 
Joined
Mar 24, 2016
Messages
19
Location
San Angelo, Tx
Sounds like it will be a very cool truck when done. Also sounds like you're working too hard to make it do what it can already do.

For more range-Long Ranger Tank from Cruiser Brothers
For more crawling-the Marlin gears are great (and sufficient to go anywhere in the USA)
For more power-Forget it
For more economy-Ride your bike to work

I would rethink the 80mph/6 inch lift/family-on-board thing. Huge top heavy truck is a rollover waiting to happen. And plus it's way over done. You can do hard trails like the Rubicon with a 4 inch lift.

My vote would be Chevy LS/NV4500/blackbox/Stock transfer. (though you might need a split case)-the parts for this already exist.

As sexy as a V8 twin turbo diesel sounds, no one in the US will know the motor or be able to get parts for it, at least not easily.

Now if you stay with an auto, you don't need gears that low. How about Chevy LS/autobox/Transfer with Marlin gears?

My real advice-drop the idea now. Buy a 200 for family duties and keep it stock, and build the 80 modestly for yourself on the side. You are not going to seriously wheel your 80 with 4 small children. Be honest with yourself.
solid advice, amigo.

You're right that i would never really attempt anything sketchy with the kids in the back. i have intentions of removing the 1" body lift and swapping 6" springs for 4", and going to 35s. might be some issues with angles.

Definitely agree that with an automatic i wouldnt need the dual case - the dual case was really only because of the manual.

I guess there's a reason why most folks on here have multiple rigs - just plain easier to have a road trip/hauler vehicle, and a crawler. with our kiddos historically we have hiked a lot more than anything else, but with a new one it's hard to carry 3, so we will likely be looking for more outdoorsy stuff to do without as much hiking until our 2nd kid is big enough to hike on her own as much as our oldest, so that we can carry the younger two. likely will just be limited to less intense trails with the kids on board, or wheeling without the family... which is not as fun.

thanks for the help, and good notes on diesel issues here in the states. LS/NV4500/blackbox/stock transfer is likely a better setup, if it would work out.
 
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