1972 Wagoneer Diesel advice needed

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eskinny
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1972 Wagoneer Diesel advice needed

Post by eskinny »

Hello All,

I am new to this forum and am still in the process of reading through all of the info, so please bear with me if I ask anything redundant. I have a 1972 Wagoneer that I bought in 1999 in a salvage yard in Lubbock for $300.00. 17 years, 4 complete rebuilds and six figures later I am finally considering a diesel conversion. My fabricator initially suggested the Duramax motor with the Allison transmission, but then I started hearing about the 4bt and 6bt. I am a noob as far as these conversions go, I am hoping to find a reputable shop in South Texas to do the work and would like to end up with a daily driver / rough country hunting ready jeep. I am interested in the opinions of the members here that are familiar with the various diesel conversions. Recently I replaced the axles with Dana 44 6 lug heavy duty axles and new 373 gears, disc brakes all the way around and lockers. We also went with 20 inch wheels and 35 inch tires. The 360 has been rebuilt (a few times) and is not quite putting out the power I would like. I would appreciate any opinions and experiences ya'll might be able to share.

thanks
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carnuck
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Re: 1972 Wagoneer Diesel advice needed

Post by carnuck »

3.73 isn't a power maker with 35" tires. It changes the factory ratio to 3.08 equivalent.
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Re: 1972 Wagoneer Diesel advice needed

Post by eggman918 »

My DD/expedition rig is a '68 F-250 crewcab 4BT ZF-5 203/205 T cases I run 3.55 gears with 33" tires and the gearing is Ideal with interstate speed limits of 75 MPH. The 4BT turns 2,000 rpm at 75 truck weighs 8,000 unloaded and i routinely tow 4,000# and have towed over 8,000# for long distances so 3.73's and 35's would put you close to where my final drive ratio is. You want to keep the B series engines between 1,800-2,000 rpm for best MPG and that is where they make max torque so you also want a turbo that wakes it boost between 1,500 and 2,300 as that is where you will spend 99% of your time spinning them faster than that is a waste of fuel, you gain little above 2,000 rpm we were out getting fire wood last weekend and we were crawling up a steep grade in 3rd/under at 1,000 rpm and the 4BT just chugged along like it was nothing but it makes well over 200 ft/lbs at 1,000 rpm and over 400 ft/lbs at 1,500 so driving style is very different from any gas motor.The two most important factors for your happiness and the rigs drive-ability are the choice of turbo and final drive ratio if you nail those the rest is just tuning and that is easy and cheap.
1967 Wagoneer soon to be TDI powered
1968 F-250 CrewCab Cummins 4BT, ZF-5, NP 203/205,TruTrac's front/rear.
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Re: 1972 Wagoneer Diesel advice needed

Post by carnuck »

The tall gears would work better with a diesel.

In a month or so, the '93 Isuzu NPR 4BD2TC with all accessories needed for the swap will be for sale (whole cube van will be up).
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Re: 1972 Wagoneer Diesel advice needed

Post by eskinny »

So the 4BT is the correct choice for this jeep? If I have to re-gear again afterwards then so be it, but I think I would try to keep the new 3.73s
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Re: 1972 Wagoneer Diesel advice needed

Post by eggman918 »

The 4BT will most likely be more costly that a 6BT, but the 6 is HEAVY and long the 4 is ~800# a bit more than the v-8's that came in Waggys and the 4 has more vibrations both 4 and 6 are tall. Power wise a well tuned 4 will be in the 200 hp 400 ft/lbs range without any fancy go fast goodies about the same as the first gen 6's so plenty for a Waggy . Depending on emission laws neither may work for you both are classified as "light heavy duty vehicle" engines by the EPA and the cutoff for that class is 8,500# GVW and up...so check your laws before spending any $$. I cannot speak directly to fitting on in a FSJ but others here can as it's been done successfully,my diesel Waggy will be powered by a compound turbo-ed VW TDI but it is a build for specific needs and I don't want 800# on the front axle and don't need the B series power. 3.73's and 35" tires with a .75 top gear will put you at just over 1,900 rpm at 70 mph just about ideal for drive ability and mileage.
For what it's worth I love the 4BT in my Ford more power than the built for towing 390 4-v it replaced and it does it using half the fuel!
Do all the research you can before drooping any coin I literally spent two years researching and sourcing parts before I started wrenching and that time paid me back tenfold in the long run....................but I was still in ~ $12,000/$14,000 :shock: by the time I was finished well as finished as a 48 year old vehicle can ever be ;)
1967 Wagoneer soon to be TDI powered
1968 F-250 CrewCab Cummins 4BT, ZF-5, NP 203/205,TruTrac's front/rear.
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Re: 1972 Wagoneer Diesel advice needed

Post by carnuck »

Since they are in such demand, 4BTs are harder to find and $$ when you do. One of the guys on here made a mounting kit for the Isuzu 3.9L turbo diesel that a buddy wanted to buy to put the 4BD2TC I have in his full size Jeep (since then, Buddy turned into a flake and abandoned 4 vehicles at my place) and the kit isn't available now.
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eggman918
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Re: 1972 Wagoneer Diesel advice needed

Post by eggman918 »

The Isuzu 4's are a bit quieter and smother than the Cummins 4's and and will make similar power.
1967 Wagoneer soon to be TDI powered
1968 F-250 CrewCab Cummins 4BT, ZF-5, NP 203/205,TruTrac's front/rear.
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eggman918
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Re: 1972 Wagoneer Diesel advice needed

Post by eggman918 »

One thing to consider on the Isuzu is the availability of transmission adapters........that could get costly with the Cummins if you plan ahead you can find an engine with the adapter that will fit what you plan to run.
1967 Wagoneer soon to be TDI powered
1968 F-250 CrewCab Cummins 4BT, ZF-5, NP 203/205,TruTrac's front/rear.
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Re: 1972 Wagoneer Diesel advice needed

Post by carnuck »

There is a guy up in BC who built an adapter to bolt the 4BD to an AW4 for his Toyota Landcruiser. That makes for a number of options other than the Jatco trans that's on it. I wonder what std trans they came with in other countries? I see std flywheels for sale quite often.
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Re: 1972 Wagoneer Diesel advice needed

Post by eskinny »

I have decided on the 4bt and am thinking about the Allison 545, any thoughts? Initially I was looking at the Allison 1000 but the 4 speed should be plenty for my application. I appreciate any experience offered.
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Re: 1972 Wagoneer Diesel advice needed

Post by Pablo »

A 545 Allison has no overdrive gear: http://www.messb.com.my/allison_at_545.html , so I hope you like going 55 MPH or less. You want to be at 1700-1950 RPM when cruising. After 2000 RPM, fuel consumption jumps greatly. Best fuel consumption to power is around 1700 RPM. You maybe could get away with big tires and a tall diff gear (what the stock busses that the 545 came out of had). It will be slower off the line and stink off road, but you could do 65-75 MPH (maybe, check with a gear calculator).

Stock, the BT series is done at 2600 RPM (defueling point / redline), so you cannot get away with a 1:1 ratio top gear like you can in a gasser. You have to get your gears (rear diff and transmission) and your turbo sorted, or you will get crappy fuel mileage and the vehicle will be a dog to drive. Use an online gear calculator to figure out your final drive line ratio for each potential driveline you evaluate. Figure out your RPM in each gear as well. I can send you my gear calculator done in LibreOffice Calc (Excel compatible), if need be.

I would look at different transmission options if you are married to the 4bt. I went with the ZF-5 manual, as I had a 4BT with a Ford small block pattern and wanted a manual (for better mileage and simplicity). You could also look at the NV series if you want a manual. For other automatics, you should look at the Dodge RF series that came behind the 6bt's. Realize, that you may need to replace the torque converter in it with one setup for a 4bt to get the best performance (you have two less cylinders than the 6bt). Further, the 4bt's came with many different bell housings, and if you don't get a 4bt with the right housing for your transmission, you will probably have to swap the housing for one that matches the transmission you go with (or buy a crazy expensive adapter from someplace like DeStroked). Factor these costs into your engine purchase decision (it is likely better to pay more for an engine with a bellhousing that matches your transmission, if all other things are equal). You might also want to find a shot in the butt Dodge Cummins RAM for parts... You can resell the 6bt in it to get your money back and use the rest for parts (including swaping the bellhousings and reusing the transmission).

Warning: Note that some 4bt's came behind TH400 automatics and have a GM adaptor bellhousing. Don't get suckered into using a GM car transmission. TH400's are just another non-overdrive transmission, and it is marginal behind a 4bt. The newer descendants of the TH400 have overdrive, but are still car-grade consumer transmissions and they do not live well behind diesels: avoid "car" grade automatics all together. Avoid the temptation of trying to hop them up too, your money is better spend on a real truck transmission than on trying to polish a turd. I mention this because every transmission shop in Amurika will try and tell you that a TH400 is Gawd's gift to the world, and they can built it to live behind a 1200 HP race car, so it is fine behind your little diesel. B.S., they may know alot about TH400's, but they don't know about diesels.

Your Dana 44 front is marginal for 35 inch tires, diesel torque and weight, and offroad use. Fine for on-road, light off-road use. I would put a 14 bolt or some other full float rear axle on it and ditch the 44 rear. They are cheap, and there is no reason to keep a 44 or AMC 20 rear with diesel torque: if you hop up the motor over stock, you will eventually break the rear (and you will hop it up... don't kid yourself) . While you are at it, you want to look at anti-torque tube's on the rear axle at least, if you don't have them already. Without them, the torque will s-bend your rear springs enough to pretzel your drivelines and kill your u-joints.

There is little wrong with your original Duramax plan, assuming you have the money to pull it off and the shop you hire is competent. It is lighter than a 6BT, and makes really good power. You have to spend lots of cash for it, it has electronics to putz with, and certain ones are better than others for longevity and swap ability. You could also put a 6bt in there, but the fit is tight and it is really too much weight to wheel/offroad with it (it is 1200 pounds with the motor over your front axle, and the bt series motors are very tall). Don't count out the 4bdt NPR Isuzu motor either.

Oh, check out the 4btswaps site. There are examples of 4bt, 6bt and NPR swaps into FSJ's and other similar vehicles.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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Pablo
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Re: 1972 Wagoneer Diesel advice needed

Post by Pablo »

Oh, and you should probably evaluate a GM 6.2 / 6.5 diesel while your are at it. Some are fans of these motors. I owned one, and am pretty bigoted against them (slow, silly things always going wrong with them). These downfalls are fixable, however, and the 6.x is a bit easier to swap and lighter.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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eskinny
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Re: 1972 Wagoneer Diesel advice needed

Post by eskinny »

I appreciate the advice. What are your thoughts about an Allison 1000 transmission?
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Re: 1972 Wagoneer Diesel advice needed

Post by eskinny »

I also have located a 5.9 12 valve locally for $1100.00, but have been told that is WAY too much motor for the jeep.
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Pablo
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Re: 1972 Wagoneer Diesel advice needed

Post by Pablo »

I think it is a bit much engine. If you are going to do it, I would buy the whole donor vehicle and not just the motor.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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Pablo
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Re: 1972 Wagoneer Diesel advice needed

Post by Pablo »

An Allison 1000 is great, but it is electronic. You will need a standalone controller to hook it to a BT series. That is probably not cheap. You could buy the whole Duramax truck with the 1000 and swap it all in (engine and transmission computer and harness ): Probably cheaper to go that route to do the 1000 than buy the controler, engine and transmission seperately
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
User avatar

Pablo
Posts: 208
Joined: Sun Dec 15, 2013 6:58 pm
Location: Arizona

Re: 1972 Wagoneer Diesel advice needed

Post by Pablo »

http://www.4btswaps.com/forum/showthrea ... ide-thread

The above link is likely to be helpful. Don't forget to investigate the available transfer cases as well.
  • 64 FSJ Wagoneer, under the knife
  • 67 FSJ Wagoneer, peacefully taking a break
  • 94 XJ, long-armed on 33's. Bolt on ghetto fab fantastic
  • 16 BU, wife's snow commuter
Formerly: 06 KJ CRD (Constantly Repair Diesel)
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carnuck
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Re: 1972 Wagoneer Diesel advice needed

Post by carnuck »

Depending what you plan to pull, I was told there is an adapter for the Isuzu motor to Chev 4L80E trans as used in TopKick General trucks. (also came with SBCs)
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