4Bts and M37s

[BobbyMike]

Can anyone who has done, or is doing, such a swap give more info on this? I know people have given out dribs and drabs, but I'm looking for a more centralized account of the swapp process.

I'm seriously considering buying one of the trucks from Dove.bid in one of the upcoming auction lot (wife has given ok to deal, very imporatnt step).

What other pieces would one need, adapters, etc?

Any hints, tips would be appreciated.

[CGarbee]

I can give you a pretty decent rundown if you need it, but please take a look at my website first...
www.garbee.net/~cabell

I've got a lot of info on my site covering my install of my 4BT in my M37...

[BobbyMike]

Duh, I feel stupid. Your site was one of the first M37 sites I ever looked at. I'll go back and look at some information I must have skipped over (as being irrelevant to my needs at the time).
Thanks!

[JimmieD]

Say, Cabell, I'm planning a swap into my Town Wagon also.

A BIG question was in choices of tranny/bellhousing. I saw some info on your site, but also stumbled into some elsewhere. A couple of guys have posted on other forums that the 6BT and 4BT have the same SAE bellhousing bolt pattern!! Further, any tranny/bell that works on a 6BT works on a 4BT. Well, I have an A-518 automatic and they were used on early 6BT, so, what do you say? Am I looking at a direct bolt-up or trouble in Dodge City?

JimmieD

[CGarbee]

They are the same familly of engine, made side by side in the same plants (one is just a short drive from me in Witikers, NC...), so, for any given version the parts swap back and forth...

For example, the first generation (12 valve, mechanical fuel injection versions) Dodge RAM parts bolt right onto the back of a first generation 4BT, and so forth.

For example, I am running a 1990 ReCon Cummins (factory rebuilt) 4BT taken out of an Entenmans Bakery Chevy P30 bread van. The current setup is: Dodge Flywheel from a 1994 Cummins RAM 4x4, aftermarket OEM style clutch for a 1994 Cummins RAM 4x4, Ford flywheel adapter from Roger at www.fordcummins.com (allows me to run a Ford specification transmission with a Dodge starter on the passenger side of the engine), aftermarket OEM style starter from a 1994 Cummins RAM, and a 1994 ZF S5-42 five speed overdrive transmission orginally fitted in a 1994 Ford F250HD 4x2. Clutch is hudraulic using the upgraded Ford 1994 Ford F250HD 4x2 slave cylinder and a Tilton remote reservoir MC utilizing the stock pedels.

The transmission uses Mercon for gear lube and if fully synchronized in all gears with a nice low first and a 0.76:1 fifth gear.

The point about mounting the starter to the passenger side is that it allows me to put the engine tight on the driver's side frame rail for maximum clearance of the front differential and to have a straight shot for the short driveshaft between the transmission and transfer case. The Dodge application fywheel adapter sticks the starter on the driver's side and it sticks out about seven inches from the side of the block... GM specifation flywheel adapter (as my engine originally had fitted) is a passenger side mount similar to what I currently am running.

My truck also has Lockrite Lockers and 4.89 gears in both ends. Have Michelin 900r16XZL's mounted on stock rims and Helitool disc brakes all the way around with a Chevy specification Bendix dual circuit MC.

I can run at 75mph all day long with a loaded truck and M101 trailer and get 17mpg on the Interstate... Of road performance is better than it was stock, as I just idle over a lot of obstructions but still have the ability to spin up the tires if I want to in mud...

Using the automatic setup from a RAM behind a 4BT wouldn't pose any problems, just strip everything off the back of the 6BT and bolt it onto the four banger...

I've got more info to plug onto my website as soon as I can find some time, so if you spot something that you'd like to know more about that is not on the website, ask and I'll post it here and will use my answers as a basis for future additions to my site...

Good luck to you both

[JimmieD]

Ooohhh, ooohhh GOOD NEWS! Thanks CG, it looks like I've got green lights all the way to Omaha.

I made a [hard] decision to stay with 2WD so this swap should be much easier. Motor mounts, radiator, fuel system, driveshaft, front springs should cover the engine install. Any suggestions on a radiator, as I currently run a 3 core desert type for the 360 so is that enough? I somehow doubt it, but....? Maybe get a 4 core soldered up?

Also I've got a 30 gallon poly saddle tank out of a '78 D200 I'm thinking of using. Any reason not to? I've read some about stock gasoline tank mods for diesel use, but thought I should ask. I can fab up a steel tank in the original location between frame rails in the rear, if I have time before the seasons change. Thanks.

[CGarbee]

I suspect that your radiator will be fine... Asside from the fact that the Cummins likes to run at 180-200F for optimum economy/performance (stock thermostat is 180F in the bread van engines), diesels as a general rule tend to run cooler than a similar displacement gasser and you are only talking 251 cu inches with the 3.9L (if my math is correct). The bread vans use the same radiator for the Cummins 4Bt and Chevy 350 powered trucks and I suspect the cooling requirements of a 350 and 360 are about the same...

Anyway, I am running a bone stock radiator in my M37 and have a radiator blanket on the truck and rarely turn on the electric cooling fan in the summer unless I'm in stop and roll traffic or sitting at idle somewhere, running the winch, etc... The bread vans use the same radiator for the Cummins 4Bt and Chevy 350 powered trucks...

As far as your tank, I think your fine with that as well. Only thing is that you will need to clean it out well (don't want either the residual gas or dirt in the system when you switch over) and add a fitting for your return fuel line (drill a hole near the current sender or fuel pickup location and use a brass elbow with a lock nut from the brake line fitting section of your local auto parts store and install it when you have the main pickup or sender out so that you can reach into the tank to hold the nut...). Plumb your return line using the same steel lines that you would use for your supply and you are all set...

Sounds like you are in good shape all around...

[Gordon Maney]

Mr. Garbee, this may seem odd, but have you ever looked at the availability of existing Cummins-fitted bracketry and compressors to allow air conditioning on your truck? Lots of street rods have air conditioning.

As I consider building such a truck for my main driver, since I have gotten soft in my old age, I like my air....

As part of such a conversion, I still think about lengthening the cab just a bit, to get more leg room.

How do you like that ZF transmission? How is the shift quality?

[JimmieD]

Thanks VERY much, CG, this is really beginning to sound good! It sounds as if it will actually be easier to swap in the 4BT than to do the mods/upgrades I was planning with a 360/A-518. Not only that, but the A-518 should live a lot longer behind the 4BT as they apparently did just fine behind 1st gen. 6BT's. I'm counting days in sweet anticipation!

Interesting idea of stretching the cab, Gordon! I assume you're speaking of punching out the firewal a bit forward; or are you looking at Club-cabbing it too? Looks like you're going to have to stretch the forum, too: Cabell, BobbyMike, Gordon, JimmieD and the rest of the 4BT guys will need a chit-chat spot?

Thanks for the help y'all....
JimmieD

[Gordon Maney]

Thanks VERY much, CG, this is really beginning to sound good! It sounds as if it will actually be easier to swap in the 4BT than to do the mods/upgrades I was planning with a 360/A-518. Not only that, but the A-518 should live a lot longer behind the 4BT as they apparently did just fine behind 1st gen. 6BT's. I'm counting days in sweet anticipation!

Interesting idea of stretching the cab, Gordon! I assume you're speaking of punching out the firewal a bit forward; or are you looking at Club-cabbing it too? Looks like you're going to have to stretch the forum, too: Cabell, BobbyMike, Gordon, JimmieD and the rest of the 4BT guys will need a chit-chat spot?

Thanks for the help y'all....
JimmieD

In simple terms, I mean increasing the dimension between the dash board and the back of the cab. Even just six or eight inches would be sufficient, allowing the seat to move farther back.

Early in the existence of these forums, I had a diesel forum. It really did not take off. I can easily add forums, but I don't want to add one if it draws only a small amount of traffic. This conversions forum works well for diesel conversions, and the 72-93 forum is suitable for those guys with original Cummins trucks. Thanks for the thought, however.

I would like to see more activity here regarding the Cummins conversions. I think the whole Frito truck frenzy that has emerged will really give this conversion approach some real energy. Although it might look a little funny, I think a person could buy one of those trucks and even drive it a while before you removed the engine.

[BobbyMike]

Thanks VERY much, CG, this is really beginning to sound good! It sounds as if it will actually be easier to swap in the 4BT than to do the mods/upgrades I was planning with a 360/A-518. Not only that, but the A-518 should live a lot longer behind the 4BT as they apparently did just fine behind 1st gen. 6BT's. I'm counting days in sweet anticipation!

Interesting idea of stretching the cab, Gordon! I assume you're speaking of punching out the firewal a bit forward; or are you looking at Club-cabbing it too? Looks like you're going to have to stretch the forum, too: Cabell, BobbyMike, Gordon, JimmieD and the rest of the 4BT guys will need a chit-chat spot?

Thanks for the help y'all....
JimmieD

Segregation? No, I like the melting pot effect! Part of my fun is reading all the threads, you never know when a bit of wisdom will pop up.

I'm going to probably buy a second truck so I can afford to take "Old Yeller" off the road for the operation. Problem is I recently spotted an old PW sitting in a farmer's field. Looks complete, don't know if it runs or not, but I'm really missing my '49 PW that I had to sell when we sold our farm.

I don't think my wife is ready for 3 trucks yet. ;(


AC in a PW, Gordon? That's a great idea, but since I'm still working on heat for my M37 I'll let you go first.

It's kinda like that old joke- When it was winter it was too cold to work on my truck and install the heater. Now that the weather's great I don't need it....

[JimmieD]

That sounds really neat to pop out the cab, Gordon! I've had more than one truck that needed it.

That was sorta tongue-in-cheek on the forums change. I'm with BobbyMike, I LOVE IT just the way it is! :~ )

[BobbyMike]

That sounds really neat to pop out the cab, Gordon! I've had more than one truck that needed it.

That was sorta tongue-in-cheek on the forums change. I'm with BobbyMike, I LOVE IT just the way it is! :~ )

I figured you were....

At 5'7" I never been cramped in any vehicle I've driven. In fact I once passed on a Mustang Mach 1 because I figured I'd need a stack of phone books to see over the hood. ;)

[JimmieD]

One of the dealerships I worked for also sold Datsuns, right at the time they changed from the Bluebird trucks to the 'later' 1600 designs. They caught on because of incredible mileage, excellent power and great handling and brakes. Problem was we had a lot of new trucks getting returned for a throttle pedal failure. The Japanese engineers, at an average height of 5' or so hadn't calculated in American numerical units. 6' 2" construction worker jumps in his Datsun after a few Colorado Koolaids after work and wants to get home to momma. The guys were punching the throttle pedals clear through the floor, leaving a gaping hole, 'cause of the short cabs and lightweight design!

There's not that much of me, BobbyMike, but I've tried to make it count sort of similar to your most excellent post in the 'Backroom' forum. Haven't replied there because you floored me with one punch.......!

JimmieD

[BobbyMike]

One of the dealerships I worked for also sold Datsuns, right at the time they changed from the Bluebird trucks to the 'later' 1600 designs. They caught on because of incredible mileage, excellent power and great handling and brakes. Problem was we had a lot of new trucks getting returned for a throttle pedal failure. The Japanese engineers, at an average height of 5' or so hadn't calculated in American numerical units. 6' 2" construction worker jumps in his Datsun after a few Colorado Koolaids after work and wants to get home to momma. The guys were punching the throttle pedals clear through the floor, leaving a gaping hole, 'cause of the short cabs and lightweight design!

There's not that much of me, BobbyMike, but I've tried to make it count sort of similar to your most excellent post in the 'Backroom' forum. Haven't replied there because you floored me with one punch.......!

JimmieD

Aw shucks!
Thanks for the kind words.