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Discussion Starter · #1 ·
I've just found the forum and really glad to have done so. I am considering installing a diesel engine in a full size Dodge van. I have access to both a 4BT, and a 6BT engine. It looks like the 6 might be a bit too large, but the 4 would work out ok in the space available. Anybody done this conversion? Any advice appreciated.
 

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Welcome olddaddy! I didn't do exactly that, but did shove a 4BT in a '67 Dodge D-100 fullsize Town Wagon truck chassis. VERY HAPPY with the results for power and mileage! Not a tire-scorching power monster, but I haven't tweaked it up yet and it still has plenty for normal driving, plus GREAT MILEAGE!

The 6BT would be really tough on front suspension as they're much heavier. Even a 4BT weighs a bit more than a 440 at about 775lbs! Had to have new front springs made with 250 lbs more lift per side, and 350 might be better. Stockers were 1,250 perside, and new ones are 1,500 per side. Personally, after driving mine for a couple of thou, I wouldn't want a 6BT, the 4BT is fine for my use in 5,500 lbs truck, mountain driving.

Your stock Dodge cooling system should be fine if it was V8 powered, and most stepvans come with a thermostatically controlled electric cooling fan. You can install a manual override switch [with lighted 'ON' indicator].

Chrysler Corp Engineering warns to never weld on a Mopar frame, except for the very end sections like a foot or so from bumpers. Heat treated steel and welding jeopardizes the metallurgy. So I fabbed up 1/2" plate steel boxes that fit inside frame channel with a longer lip at bottom that motor mounts fit on. I used stock 440 mounts and they're okay, but not great. Some vibration but mine were old tired used things, might as well have been steel biscuits. Boxes beef up frame and distribute loads.

The clearance for exhaust, the curved section called the 'down pipe' coming out of turbo, can be tight and you will undoubtedly have to fab up an exhaust. You can re-use what comes in a stepvan and weld it up to fit if you get a couple of aftermarket bends. Frame crossmembers will probably have to be moved or fabricated, again without welding/cutting on frame rails, but not a huge problem. I'd suggest a Dana 60 rear instead of the Mopar 8 3/4", but the latter would do the job in light duty. You may want to think about an exhaust brake especially with an automatic in the mountains. Also power steering & power brakes. Some issues there but they can be solved.

Post questions as needed as lots of guys with great advice around here!
 

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Discussion Starter · #3 ·
JimmieD, thanks for the reply. I talked to a local shop that does a lot of 6BT work and they werer pretty enthusiastic about the 4BT. I've got some measuring to do, but I'm hopeful. I found an engine locally and if the seller is at all reasonable I'll buy it. The company I work for is going into full biodiesel production for our 30 truck fleet and fuel will be available to me for free!!!! I currently spend $500 a month just getting to and from work! It's a diesel world for me from here on out.
 

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JimmieD, thanks for the reply. I talked to a local shop that does a lot of 6BT work and they werer pretty enthusiastic about the 4BT. I've got some measuring to do, but I'm hopeful. I found an engine locally and if the seller is at all reasonable I'll buy it. The company I work for is going into full biodiesel production for our 30 truck fleet and fuel will be available to me for free!!!! I currently spend $500 a month just getting to and from work! It's a diesel world for me from here on out.
Man, that is flat incredible! Somebody up there likes you :)
 

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Welcome olddaddy! I didn't do exactly that, but did shove a 4BT in a '67 Dodge D-100 fullsize Town Wagon truck chassis. VERY HAPPY with the results for power and mileage! Not a tire-scorching power monster, but I haven't tweaked it up yet and it still has plenty for normal driving, plus GREAT MILEAGE!

The 6BT would be really tough on front suspension as they're much heavier. Even a 4BT weighs a bit more than a 440 at about 775lbs! Had to have new front springs made with 250 lbs more lift per side, and 350 might be better. Stockers were 1,250 perside, and new ones are 1,500 per side. Personally, after driving mine for a couple of thou, I wouldn't want a 6BT, the 4BT is fine for my use in 5,500 lbs truck, mountain driving.

Your stock Dodge cooling system should be fine if it was V8 powered, and most stepvans come with a thermostatically controlled electric cooling fan. You can install a manual override switch [with lighted 'ON' indicator].

Chrysler Corp Engineering warns to never weld on a Mopar frame, except for the very end sections like a foot or so from bumpers. Heat treated steel and welding jeopardizes the metallurgy. So I fabbed up 1/2" plate steel boxes that fit inside frame channel with a longer lip at bottom that motor mounts fit on. I used stock 440 mounts and they're okay, but not great. Some vibration but mine were old tired used things, might as well have been steel biscuits. Boxes beef up frame and distribute loads.

The clearance for exhaust, the curved section called the 'down pipe' coming out of turbo, can be tight and you will undoubtedly have to fab up an exhaust. You can re-use what comes in a stepvan and weld it up to fit if you get a couple of aftermarket bends. Frame crossmembers will probably have to be moved or fabricated, again without welding/cutting on frame rails, but not a huge problem. I'd suggest a Dana 60 rear instead of the Mopar 8 3/4", but the latter would do the job in light duty. You may want to think about an exhaust brake especially with an automatic in the mountains. Also power steering & power brakes. Some issues there but they can be solved.

Post questions as needed as lots of guys with great advice around here!
FWIW, the 89' Dodge D250 with a 6BT had 1915 lb. springs...
 

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FWIW, the 89' Dodge D250 with a 6BT had 1915 lb. springs...
Thanks, good info Dakota. My 1,500's are j-u-s-t enough but a smidge more sure wouldn't hurt even with a 4BT.

There's some pics of my truck at the link, pics #38-42 inclusive, and 58-66 inclusive:

http://imageevent.com/moparnorm/townpanelswagons;jsessionid=20rtzht6u1.tiger_s

Mopar Norm is a good friend and I believe his site there is the largest gallery of vintage Dodge civilian, military, 4WD truck etc photos on the entire net, or maybe anywhere in existence!
 

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Another Van Conversion Prospect

I've been researching converting my van to a 4bta power plant.
The prospect is a 94 B350, 4k front axle, Dana 60/6k rear axle, Maxi-wagon.
Present mill is the 5.9l V-8 w. OD automatic. 87k miles on the clock. 9mpg.

The 4bta with the Dodge 6bt automatic seem like a natural. Certainly, the 4bt would be a better fit than the 6. Plenty of torque, too. This is a work truck. The extra weight of the 6 isn't needed. Besides, why go overboard on torque? I want to drive this truck. Not replace twisted drivetrain components as a hobby.

I also plan to do a Ramcharger AW150 or A150.
 

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I'm on the fence right now as to what I will swap into my '87 E350 4x4. A 4BT is at the top of the list though. A 6.9/7.3 would be a bolt-in as they were available OEM in it. I like them as basic reliable engines but they can't return the fuel economy that the Cummins does. If I go to the trouble of swapping on a van I want to make sure I get the most for my time/effort, and I'm not talking about power. My performance interests these days are of economy not power. I suppose I'm acting older than I am...

Ken
 

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Hi New user here,
I have a 91 dodge b350 Xplorer camper van with the 5.9 gas engine, and electric overdrive transmission. I am curious about a 4BT cummins engine swap, I am currently averaging 9.5 mpg city and 11-12 mpg highway. I would be real happy with high teens or higher with diesel power. My last camper a 92 27' safari trek got 14mpg highway on the 3.9 Isuzu diesel 4 cylinder. but was too large for my needs. Any ideas on possible mileage with the 4BT my van weighs around 6800bs loaded.

91dodgeb350
 

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Welcome to the forum!

My 2WD Dodge truck I mentioned above is probably 6,800 lbs also. I used NV4500 5 speed & 4.1 gears with a 4BT. I've changed the compressor side of turbo to about HX35, and added a 3,200 governor spring. Truck isn't tweaked, basically stock engine except as mentioned.

On one long trip, unbelievable to most folks, I averaged 32 mpg. Some felt there was some kind of error factor, I don't. However even assuming an error it would be small as speedo accuracy was checked by CHP on radar, and I filled up at the same pump the next day, so knocking off a couple of mpg still leaves 30 miles per gallon.
 

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...speedo accuracy was checked by CHP on radar...
Hey Jimmie, speedometer accuracy is separate from odometer accuracy. I don't know the why but it is so. It's unusual to have both the speedo and odo be accurate to the same degree. If one is accurate the other is off. Thus if you have a very accurate speedometer, you likely have some inaccuracy in your odometer. Perhaps the TW got even better mpg than you think.

My '87 E350's speedo is accurate to within 1 mph at 45 mph but is ~10% off in the odometer. It used to be the opposite with the factory size tires: 235-85R16 OEM, now 255-85R16.

My wife's '01 Yukon XL is very accurate on the odometer but is off by 2-3 mph on the speedo with OEM tires.

Ken
 

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Thanks, that can be useful information. That is if the average guy can have his odometer easily tested for free to determine the accuracy. Unfortunately that can't be done.

So, that leaves us to use the best we have and make the best measurements we're able to and go from there. In many routes of travel it's virtually impossible to accurately determine the exact & corect miles covered, so all we have is that little odo, humble as it is, with its error factor. We might add map mileage info and get closer to correct.

One thing that's surely inaccurate is highway mileage signs, like 'Chicago 3 miles'.
 

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JimmieD So are you saying I could possibly get around 30 MPG with a 4 BT? I am new, real new at this.
91dodgeb350
I think you'll find that most people get mid to low 20's in full size trucks. Some get more than that, some get less.
 

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I would say yes, except for the trans. Even an o'd automatic trans has losses in it that simply cannot be overcome with current technology & available parts.

In addition the answer depends on many other variables, such as exact type of axles, axle ratios, exact type & size of tires, general mechanical condition, related mechanical adjustments, type of brakes & adjustment, state of tune of the engine, specific types of lubricants used etc.

In Mopars the two best 2WD rear axles for economy are the 8.75" [8-3/4"] or the Dana 60HD, as these have the least parasytic loss from bearings etc. followed by the 9.25". The D60HD is far tougher than the 8-3/4 or 9-1/4 and has full-floating axles.

Overdrive manual trans is going to give better mileage than o'drive automatic. Synthetic lubricants can and usually do have greater lubricity. Wheel bearing & brake drag can rob you, and soft toothy tires require more energy to spin.

If a guy goes out of his way to do the homework & educate himself and gathers the correct pile of parts and assembles it fastidiously, yes, 30mpg is very possible. The auto trans can cost you 2-4mpg on average.
 

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Converting a Dodge Van Charger 4x4 to Diesel power in the Ventura county

Good Morning,
I have a 84 Dodge Van Charger 4x4 that is running on a 360 and is doing ok at this time. Gives me time to fiqure out the best swap for my van.
I would like to know more of the ca. rules on engine swaps, so when complete you just register at the DMV and done. That's hard to do in ca.
Power and performance comparing to a 360 gas engine leads me to the 6, but weight and overall size in a van may not fit. Anybody try shoe horning
a Cummins 6 in a van? Have No experiance with the 4, Would the 4 be a reasonable choice for a 1 ton van?
I would really like to connect with a shop in VTA that could point out some of the issues that need to addressed, any info apprieciated.
 

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My Dodge truck, a '67 Town Wagon, weighs about the same as your 84 van, mine probably has a little better aerodynamics. I removed a stongly built 360 with the right heads for performance plus a cam, headers, fairly open dual exhaust, Edelbrock intake & 4bbl & other goodies. My Cummins 4BT gave virtually the same performance, but with more pulling torque off idle. After some pump tweaks, 3,200 rpm governor spring, turbo swap to about an HX35, open exhaust it has more power than the 360. However mine has an NV4500 5 speed manual, which delivers more engine power and better mileage than an automatic.

The CA SMOG regs require the emissions equipment to match the year of vehicle, everything that would be required, and the year of engine as well. Because you'd upgrade to a diesel then engine would be required to have all the diesel SMOG equipment: which is none. Most of the Cummins engines out there now are 1990 Cummins Remanufactured and for '90 no SMOG stuff was required. No SMOG stuff for your 360 gasser engine is required because you're removing it.
If you got a later Cummins that might have some SMOG items you'd have to have those in your build. You'll have to check & see if a catalytic converter is required for your year model and if so you'd have to install one, long enough to pass SMOG testing.

You might drop by a local SMOG test garage and double check with them, but far as I know this is correct info. I'm in CA.
 

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Just to clarify a few things from my posts above: my truck was around 5,500-5,800 lbs pre-Cummins, now it's about 7,200-7,500 or so with diesel, NV4500, heavier rear axle etc. I originally purchased brand new Eaton Detroit Springs for the front, which they rated as 250 lbs overload per side, so 500lbs overload factor. They cost me a chunk, especially shipping. The 360 I pulled out weighed about 700 and trans 100, Cummins about 900 and trans 200, so I should have been fine.

Within 3 months the brand new Eaton Detroit Springs were flat and by 5 months the front spring shackles were resting against the frame. Eaton wouldn't work with me and would only allow that if I shipped them back they'd 'Inspect' them. If they decided there was a problem they'd credit me, if not, my problem, plus I'd have to pay shipping back to them and again on any replacement springs, so 3 times the original shipping. They cost of the shipping to do all that was more than a set of springs.

I ended up yanking them except for first leaf with eyelets, got the rear spring leaves off a '49 Chevy 3/4 ton and installed them with the primary leaf. Far better and still hanging on a few years later in 2013!

RE: mileage, I've gotten 32mpg out of mine on longer trips, much less in the mountains on short trips. Running 4.10 gears and 235/75-16's. Changed tire size to about 2" taller, wider & softer with traction tread and super mileage went to hell!

It's all about gears, Gears, GEARS!
 
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