Figures. Now tha the truck is 95% of the way there, I finally find the engine I wanted to start with.
4BT Cummins.
Picked it up 2 weeks ago from a guy that parts the bread vans out. was an hour away, and I only paid $1200 bucks for it. 130K miles on it. Runs good, fired right up once we got the air out of the injection system. Has the serpentine belt drive, gear drive power steering pump, and high output alternator. Needs a good cleaning, has some oil leaks here and there but nothing major.
Big issue I am going to have is the driveline. Came with a Ford T19 bellhousing. The Cummins Dodge bellhousing adapter still won't mate to my NP435, even if I had the right parts, as the 435 never came behind the cummins from the factory and the bolt pattern is different so, no matter what I do I will ahve to mix and match parts if I want to keep my current transmission, which I do. The good news though is that the Dodge transmission has a 8 3/8" input shaft, while the Ford is 6 1/2, which leaves me 1 7/8" between the ford bell and Dodge trans to make an adapter. Already took some measurements, and should be pretty easy to do, just a 1 7/8" thick hunk of aluminum, drill a 5.25" hole in the middle for the Dodge input bearing retainer, then 6 mounting holes. The dodge transmission shares the same upper two holes as the Ford. I figure I will put the Dodge disc under the ford pressure plate, and call it a day, or, if I get lucky, my Dodge pressure plate might even bolt to the cummins flywheel.
So, I am sure many of you think I am nuttier that squirrel poop at this point, but, I finally found the engine I should have started with. Looked back two years ago and couldn't find anything within 1500 miles for under 3000 bucks. On the bright side, this should be much easier to install and get running properly!
Isn't that the way it always goes. You can't get the one you want so an alternative comes your way and then when you're just about done the orignial shows up. I have a feeling you just enjoy the wrenching part anyway... I look forward to the pictures of your work as you move along. A lot of people use the NV4500 transmission because it has the 5th gear in it. Any thought to picking one of those up? Would make matting it up with the a dodge bell houseing and clutch plate etc (all can be gotten from a 6BT out of a dodge pickup BTW) easier.
If I had the money available, rather than build an adapter, I would seriously look at a Ranger Overdrive unit from Advance adapters. It fits in front of the trans, and can be used as the adapter. Plus you get the benefit of a 27% overdrive that can be used with EACH gear! (8 forward gears and two reverse gears could be handy with the narrow power band of the diesel...)
Thats EXACTLY how it always seems to go. I have thought of the NV4500. I would love one, but, I need to liquidate some of my "inventory" first if I am going to afford such a beast. I have a big block 440, a NP435 good for parts, a few intake manifolds, a cylinder head off a big block, two superchargers and a whole host of other random stuff I need to ditch, not including the 400/435/203 in the truck already... If I could get rid of some of that stuff and get decent cash for it I could afford the 4500. Then I could bolt a Chevy NP205 to the back, make some custom driveshafts and call it a day!
Ray, I have heard BAD things about the advance adapters overdrive unit when run behind a torquey diesel. Cabell actually had one in his 4BT swapped M and broke it after a not very long time. He was NOT happy. Its a pretty pricey little gearbox to be breaking.
basically have 4 options of varying cost and complexity:
1.Make the adapter plate, use the current transmission and T case
Pros:
-Cheap, should be under $300
-99% sure it will work
-all one unit, nice and short. Makes the rear driveshaft longer, better angle of operation, U joints last longer.
-reuses many of the parts I have already paid for and have into the truck.
-keeps the full time 4WD
-Most of the mounting work is already done, no new mounts to build or test.
Cons:
-engine position is locked. Can’t move the engine, as the transmission is where it is, and the engine bolts to it, so, wherever it lands, is where it has to be.
-custom parts. Custom parts can be a pain if they break.
-Full time 4WD will hurt fuel economy.
-4 speed transmission is non overdrive. With the stock Cummins governor, top speed will be limited to about 63 MPH. Engine will turn 2150@ 60 MPH. This is above the torque peak, so, I will not get as good a fuel economy as I could with a 5 speed transmission.
2.Put in the Ford T19 2wd transmission, use Dodge NP205 T case.
Pros:
-Cheap still. Not as cheap as #1, but, still cheaper
-simple, reliable transmission and T case. Easy to find, easy to fix.
-damn near unbreakable. The toughest transmission and transfer case ever put into a light duty pickup truck.
-Part time 4WD will get better fuel economy. Less drag.
-Bolts right to the Cummins, no custom parts needed.
-Separate transmission and T case are easier to service.
-Engine position is unlocked. Since I have to make new mounts for anything, I am free to move the engine forwards or backwards now if I need to.
Cons:
-loose full time 4WD. Only a problem on very slick surfaces, where, it should be locked into 4WD anyway. Not a big deal.
-separate cases mean twice as many mounts to build, and a longer drivetrain, which means a shorter rear driveshaft. U joints wear out faster in shorter shafts.
-Will take more time to install than #1
-Non overdrive transmission. See speed and fuel economy on #1.
3.Ford T18, Chevy NP205 modified to bolt to it. All one unit.
Pros:
-All one unit. Nice, short, sweet. Better driveshaft angles, longer U joint life.
-unbreakable, same as #2, only the transmission and T case are bolted together.
-Same cost as #2.
-Part time 4WD will get better fuel economy. Less drag.
-Bolts right to the Cummins, no custom parts needed.
-Engine position is unlocked. Since I have to make new mounts for anything, I am free to move the engine forwards or backwards now if I need to.
-Bolted together means fewer mounts to make. Might be able to modify the one I made for the current transmission and use it.
Cons:
-loose full time 4WD. Only a problem on very slick surfaces, where, it should be locked into 4WD anyway. Not a big deal.
-Will take more time to install than #1
-Non overdrive transmission. See speed and fuel economy on #1.
-bolted together means that if anything needs service, a bunch of stuff has to come apart. All big, heavy, cast iron boxes. Likelihood of having to service anything is slim though.
4.NV4500 Transmission, NP205, married together to one unit.
Pros:
-5 speed. RPMs drop 27% in 5th gear. 1600 @ 60, 1850 @ 70. Perfect. Top speed is now much faster than I would ever want to go in it. RPM @ 60 MPH is perfect for peak fuel economy. Might get 22-24 MPG with the proper gearing in it, as opposed to 16-17 with the other transmissions.
-All one unit. Nice, short, sweet. Better driveshaft angles, longer U joint life.
-unbreakable, same strength as #3
-Part time 4WD will get better fuel economy. Less drag.
-Engine position is unlocked. Since I have to make new mounts for anything, I am free to move the engine forwards or backwards now if I need to.
-Bolted together means fewer mounts to make. Might be able to modify the one I made for the current transmission and use it.
Cons:
-loose full time 4WD. Only a problem on very slick surfaces, where, it should be locked into 4WD anyway. Not a big deal.
-Will take more time to install than #1
-The big reason: VERY EXPENSIVE. Everyone wants this particular combo, so, it is expensive. Would take about $2K to do this one…
-Needs an adapter plate to bolt to the Cummins. Adapter plate is currently available though online for $275. Don’t have to custom make it myself.
So, obviously, of money were no object, I would do #4. #4 mechanically is the best, hands down, no challenge. Depending on how much the adapter plate for #1 is, that will determine my route I think. If the plate is going to be $400-500, I’ll do #2 or #3 first. With #5, 22 MPG is a 37% increase in fuel economy. I plan on 5K miles a year on this beast, so, at 16 MPG, that’s 312 gallons of diesel. At 22, that’s 227. That’s a difference of 85 gallons, at 4 bucks a gallon, that’s a fuel cost difference of $350 bucks a year, meaning the payback on the parts from a simple fuel economy standpoint is about 4 years ($2000 Vs $500 in parts costs).
So, not sure if that makes sense or not. The other big benefits though are top speed and noise with the 5 speed. The engine is governed at 2300 RPM, so, currently, to run 65 MPH, I’d be right against the governor. You can turn those up to though to 3300 RPM, so, that’s not a huge deal.
Josh, if you mind, who did you get the 4bt from. I'm going to be doing the same swap in the near future. Could use a good source for the motor. Thanks Ron
Personally I would wait until I had enough cash and go for the best option overall, which appears to be No.4
To me its a no brainer, especially the increased mpg and low rpm.
You only want to do this once so why go the inferior route and end up kicking yourself later when you could have the best available option.
Sell off some stuff you dont need and start saving!
Cheers
Stu
1952 Dodge M37 with 1952 M101 Trailer
MVT UK
SMVG Scotland
Go with the NV4500. You know you'll be much happier in the long run. There's a reason everybody wants one its a really nice gearbox. You may luck out and find one for less than 2k. Make sure you get the upgraded 5th gear though. I drove a 97 dodge dually with the 6bt that lost 5th gear 3 times before they came out with the fix for it.
Got it!
Ford used the ZF5 S-42 5 speed overdrive transmission from 1987 to 1995. Has the exact same bellhousing, input shaft length, spline count, and bolt pattern as my T19 bellhousing, and, it has a 5th gear overdrive of .76:1! Will bolt right to the back of my cummins as-is! From there, I can get a Chevy NP205 with the 8 bolt "racetrack" bolt pattern, convert the Chevy 205 over to the regular ford 6 bolt round pattern with a northwest Fab adapter plate, put a ford 31 spline input gear in it, and DONE, it all bolts together with no major changes! Best part is that all those parts are cheap and easy to find. I can do this for less than half the cost of the NV4500/205 plan.
Ron, the guy's name is Jeff, and his number is 920 Six Five Five 4531. He had one engine left, but, I believe that he parts these trucks pretty regularily. He was a cummins mechanic on them for 18 years so, he knows his stuff.
Thanks Josh, I'll save his number. I'm planning on using the 2 1/2 ton Spicer 3053A transmission. I've got one in my deuce and it works great. Good luck with your build and look forward to reading about it. Ron
The other thought I had...not to talk you out of your set up because that sounds like a good one and it sounds up your alley...lots of engineering and stuff....but, what about the transmission out of the M35a2 duce? I could be wrong but I beileve it will bolt right to the cummins also as it uses a SAE 3 bell housing and it is a 5 speed also. Cept you'll have to have the divorced transferecase with it. Just throwing it out there for fun.
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I look forward to the pictures of your work as you move along. A lot of people use the NV4500 transmission because it has the 5th gear in it. Any thought to picking one of those up? Would make matting it up with the a dodge bell houseing and clutch plate etc (all can be gotten from a 6BT out of a dodge pickup BTW) easier.
