440 to diesel conversion: Pros & Cons?

Started by Firemansred, July 11, 2012, 10:03 PM

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Ok. I have been watching this forum for a while now. I am working on swapping an Isuzu 6bd1t in my winny! I bought the engine for 1000.00$ Tranny is going to cost me just because of the power and the way that a diesel makes power! Totally different from gas!
   There is where this swap shines! Not just from the increase in economy but also the fact that you have so much more pulling power! Remember diesel is a work horse of the internal combustion engines! They don't put them in trucks for no reason! Part of my reason is that I am tired of pulling hills at 25mph!

Have a friend that has a 30' winny with a cummins in it. Took it to Mopar's on the strip in Vegas from up in Idaho gvw was 28000 with 7 people and the car trailer! Averaged 14mpg high of 18mpg low of 12!!
   Friend on 4bt forum is helping with the tranny adapter says with 6bd1t should get 12-15mpg and pull the hills at 45mph!

This is what I have learned so far! Hope it helps!


Well after all these years of pushing a Winnie around 318-440 the best after all the talking/converting etc: etc: etc: the best anyone has done is 15 to 20 and I really think that was at midnight, down hil,l with a tail wind. The realistic figures I've heard is 8 to 10 at best but I think the real numbers are a little more around 5 to 10 averaging 8 under normal constant highway driving. If your look for the big numbers in mileage you might want to check out the link I just posted. That's just my take on it. Ok boys let the fur fly. :laugh:



Noticed today that the Travco converted to diesel in the link above is now up for sale.

Following up on the engine mounts, I also made contact with Michigandon. He did a Cummins conversion in a Travco as well. It can been seen on youtube and he confirmed that the 89-93 Dodge Ram engine mounts will bolt up to the factory 413-440 frame mounts on the Dodge chassis. The only change involves flipping the rubber isolators and the bolts line up. IMO this makes the swap much easier for Dodge powered rigs.


No dice on the stick shift Chieftain. A main floor support above the chassis is right where the shifter needs to come up. I won't be cutting through that so its back to a wife friendly automatic and the Gear Vendor overdrive behind the Cummins if this ever plays out.


I don't want to get to far ahead of myself but this is on my to do list. Starting to take measurements, make a few calls, and do a lot of studying. The plan is using the 1989 Dodge Cummins, 5 speed manual(been driving Cummins diesels for 15 years and never had, wanted, or trusted an automatic LOL), NP205 transfer case with a Gear Vendor overdrive mounted to it. It gives a real nice gearing setup with the 4.56's in the Dana 70HD and being able to split gears with the gears vendor is really nice in a big heavy rig like this. The transfer case is only being used because I have it and it makes the Gear Vendor install a snap. The added benefit is a 2:1 gear reduction which would be nice for creeping in and out of some campgrounds. I have got to get an intercooler in there, switch exhaust manifolds, maybe a turbo upgrade, and pipe it all together.  Lots of stuff to consider. I guess I better get the interior done first. D:oH!


Your welcome.  I do not have a clue about diesel stuff but knew there was a lot of good information in all those pics.   Even the 440 pics are useful for pointing out things.

Good Luck,



Thanks for posting that link Dave. I had seen it previously but not looked at it in some time. I have been thinking about this and would love to convert my Chieftain over to diesel and store the 440 away for safe keeping. I have a 1989 Dodge parts truck with a Cummins that would be an ideal donor.

I do want to mention the diesel in this swap is a P-pump 94-97 Dodge engine. The chassis changed in 1994 and shares nothing with the earlier trucks. I think using the earlier 89-93 Dodge version would be easier in some respects. I believe the motor mounts and frame are very similar between the truck and motorhome chassis. The 440 to diesel swap in a standard pickup is a bolt in deal. Some small shimming may be required and I am going to investigate the mounts further. The injection pump is also smaller on the 89-93 so the engine may not be quite as hard to position. My diesel is not intercooled so that would eliminate some problems also. I recall reading that the exhaust manifold from a Ford bus application is low mount to get that fitting better.

Lots to measure and think about but it would be a cool swap.


I know this subject occasionally comes up and ran across this pictorial of converting a M400 440 chassis in a 75 Travco to a diesel.  From the chassis perspective, M400 is a M400.  Lots of pictures and sort of puts things into perspective.




Sent: 4/29/2005 12:52 PM

Here is some info about Perkins engines used in Dodge trucks:



Aaron Arnold's W-300 Diesel (PW-300?)
Images submitted by Aaron Arnold.
Aaron Arnold of Boerne, Texas, owns this one of a kind Perkins Diesel powered W-300. The truck is the only Perkins Diesel powered W-300 known to exist and one of a rare few W-300 Crew Cab Trucks. Although originally equipped to haul horses, the truck now has a Utiline bed on the rear of the chassis (see photos below). This unique truck has the following specifications:

    * 354 ci Six Cylinder Perkins Diesel Engine, English built (Eng. # 8044081)
    * 146" wheelbase
    * NP 420 Transmission with special bell housing
    * NP 201 Twin-Stick Transfer Case
    * Dana 70 Front and Rear Differentials (4.88:1 gears)
    * Dual Rear Wheels
    * MU-2A Braden PTO Winch (10,000lb capacity)
    * Dual Batteries
    * Dash mounted Throttle Pull Handle
    * Mechanical Tachometer with hours meter
    * Medium Duty Truck Steering Wheel
    * Full Length Running Boards
    * Power Brakes with Vacuum Pump and reserve tank
    * Diesel Fender Emblems under Dodge Emblems (same script)
    * Cold Weather Start decal, pull knob and ether bottle on firewall
    * Pull to Stop Engine decal with knob
    * Use Diesel Fuel Only decal along with 20 gallon tank behind seat
    * Chrysler Perkins Industrial Diesel decal on valve cover
    * Bostrom Viking T-bar seats (possibly a dealer installed option)

    * Interesting Statistics: PW-300 Curb Weight: 6,860lbs
    * Gas Mileage: 17-18 at 65 mph
    * Engine Oil Capacity: 16.5 quarts


Sent: 4/29/2005 2:21 AM

I had an old rusted out diesel VW Rabbit pickup truck for years (back in the late 80s).  Back then diesel was CHEAPER than even regular gas in Connecticut, and that ugly little truck got 40 mpg!  It was damn ugly, smelly, and the engine was loud and clackity...but it had over 300,000 miles on it, ran like a top, started on even the coldest days, and like I said, got 40mpg.  I finally had to junk the poor thing when I went over some railroad tracks and the bed folded into the cab from the rust...lmao.

Kev and Patti Smith
Kev and Patti, the furry kids, our 1981 Ford F-100 Custom tow vehicle, and our 1995 Itasca Suncruiser Diesel Pusher.


Sent: 4/29/2005 12:17 AM

I have an old Dodge motor home I was planning to convert to diesel. While I was trying to decide whether to use one of the engines I have or wait for a good deal on a Cummins to turn up, I came across a '78 Elandan II 27 foot that had already been converted.  It has a Perkins 354 turbo, the original 727 tranny and a Gear Vendors overdrive. The present owner didn't do the conversion so I don't have a lot of information about how it was done or how hard it was. I'd welcome any comments on this combination (what kind of performance to expect, anything to watch out for, etc.)  If I do buy it, I'll try to keep the forum updated on how it works.


Sent: 4/15/2005 7:50 AM

Thanks for the info Denison! Strange that you seem to have had so many negative experiences with diesel engines, mine have all been far better than my experiences with gasoline engines.

I agree with ideas of your "fuel supply", I wasn't going to mention that, being that it is "not exactly legal" to run non-tax fuel on the highway.

The longest I have owned a diesel powered vehicle was during my 4 years in the Navy. It was a 1980 Volkswagen Rabbit diesel. I chose this vehicle because of the fuel mileage (45-50mpg consistently)  During our time out at sea, my car would sit on the base for months at a time. When I would return, It would always fire right up (using the glow plugs) and simply chug away as I used a small 12 volt air pump to re inflate the tires.

On my duty days, my buddies would always ask to borrow my car. Being that I didn't own anything at the time and did not fear a lawsuit, I would always let them use it. You can rest assured it was treated like a rental car while they were using it...lol
On the other hand, I wasn't very gentle with the car either. One of my favorite tricks was to pull up beside one of my buddies and rev the engine slightly and drop the clutch. The high torque diesel would burn the tires til they would smoke, while the engine belched black smoke out the exhaust pipe. My buddies always got a good laugh out of that. (Did I mention that in four years I put 2 clutch kits in as a result of this abuse!)

My buddies and I ran the crap out of the car for four years and I drove it from San Diego back to Ohio after I got out. When I got back home I had a car and a truck in storage that I owned before I joined the Navy, so something had to give. I made a mistake that I still regret. I sold the Volkswagen with it perfect condition southern CA body and rock solid diesel engine with 274,000 miles on it.

I have owned several diesel powered trucks, but I think that it would take at least a year of driving to give a fair evaluation. Each of these trucks were purchased at repo auctions and sold within several months after I purchased them. But I can say that Blue Book values for diesel powered trucks are always higher.

At my work, we have a John Deere diesel powered loader used to move coal. This engine has some of the worst operating conditions for a diesel engine(or any engine for that matter). It is started and run each shift for about 10 minutes at a time and is used 24/7 365 days a year. The engine has not been rebuilt and the only problem we have ever had was a lift pump going out. It starts first time, every time!

We have several gasoline forklifts that don't get used nearly as much or under the harsh conditions as the loader. After cranking and cranking and sometimes priming the carb, they will start.

On the other hand, remember all of the problems I had with the "mystery miss" on my 440 in my Apollo. What about the "little or no vacuum" thread here that was so similar to the problems I had. I have never spent weeks chasing a miss in a diesel engine.

I have a 1988 Dodge Dakota with a 3.9 V6. I purchased the truck 5 years ago with 79,000 miles on it. It now has 90,000. The list of things I have had to repair on this truck is unreal. On a good day, with the truck completely empty, I am lucky to get 15 mpg. It is a standard shift 4 speed with OD!

When a diesel engine stops running altogether, it is almost always due to a lack of fuel. (Usually a lift pump). It is possible to have injector problems and other issues, but this usually will only drop one cylinder or cause the cylinder to miss-fire.

One the other hand, If my gasoline engine in my motor home were to quit while going down the highway, it could be an ignition switch, coil, cap, rotor, points or electronic ignition, a loose wire, lack of fuel the list goes on and on....

All of the above is simply my opinion based upon my personal experience. Regardless if it is diesel, gasoline, or some type of hybrid, I would like to see our country focus on more fuel efficient vehicles.

Congratulations again on your retirement Dave!
   Isn't today the big day? 4-15-2005?


Sent: 4/14/2005 9:55 PM

I haven't seen any internet scuttlebutt about older diesel engine performance, like ones used in vehicles in the early 70s. That would be comparable to the V8 gasser in my Winnebago.
I worked with a guy who bought a new diesel Oldsmobile when they came out. Was that in 78? He was very happy with it, even after the crankshaft broke when he was driving back from his families vacation in Wisconsin, at about 49,500 miles on the 3 year old car. The warranty was for 50,000 miles or 5 years, so General Motors installed a new crankshaft for him, and paid for his rental car too.
He was getting 22-24 mpg on the highway, about 18-19 on his commute to work. He sold it before it had another 49k miles on the new crankshaft though.
I had a Mercedes Benz 180D for a while, I forget whether it was a 1956 or a 58. It had 180k miles on it, but its crankshaft had been replaced at 100k miles - after it snapped in the middle. The car was given to me after the dashboard caught fire, but I fixed what I needed to, including replacing the windshield and gasket.
It ran okay after I dismantled the injector pump and put in new "O" rings, (a tricky chore, but I wasnt going to pay for the cost of a rebuilt injector pump!!!) but it did not have much power; lots of shifting on hills in West Virginia and Western Maryland. I never felt inclined to use it for general transportation, and when my supply of overage home heating oil was about gone I gave it to a guy who had access to an 1100 gallon tank of agricultural diesel fuel on the farm where he worked. (like home heating oil - no taxes on it.)
My landlady bought a MB 300D when they first came out. That winter she was concerned about how long it took to start, when the temp. was in the single digits. I showed her that she could just repeat the cycle of "ign-on, let the glow plug tell tale go out, ign-off and ign-on again. etc". If she did that 3 or 4 times, it would start okay even at zero fahrenheit. She said it might be hard on the battery; so I opened the hood and showed her the size of the battery. She was reassured.


Sent: 4/14/2005 8:24 AM

Here is some more info that I found on diesel engines. In another gas to diesel conversion thread, I mentioned the diesel powered Jeep Liberty. I found a review of the 2005 Jeep Liberty on allpar.com. I was mistaken about the diesel engine used in the Jeep Liberty. I thought it was the Mercedes diesel like the ones used in the Sprinter chassis, this article states that it is a Detroit diesel.

Here is a quote from the article with some interesting info on diesel engines:

Diesels are available on every Jeep model sold in Europe, from Wrangler to Grand Cherokee, but in America cheap gas and cheap cars, combined with troublesome and smoke-belching 1970s Mercedes and GM diesels, made the efficient but more expensive engines fairly rare outside of one-ton pickup trucks.

Diesel engines are common in Europe because they offer higher gas mileage and greater longevity; in a continent where people tend to keep their cars longer, and where fuel is more expensive, these factors offset the higher initial price. So does their lower maintenance (oil changes every 12,500 miles, for example), and their terrific torque at low engine speeds, which is handy in city traffic. Their roughly-20% lower carbon dioxide emissions are handy, too.

As an added factor in their favor, diesels can run on "grown and distilled" fuel - that is, biodiesel, which is a fluid with diesel-like properties made by distilling almond oil, soy, or various garden wastes. Biodiesel is grown naturally, does not require lots of outside energy for distillation (as alcohol and hydrogen do), and, when spilled, is generally not toxic. People can actually grow their own biodiesel fuel; Chrysler uses a 5% bio fuel ("B5," see sidebar) for Libertys as they leave the factories, but research has shown that pure biodiesel can be run in Cummins turbodiesels (used in Ram trucks) with no harm, and we suspect Libertys can run it equally well. (Pure biodiesel is fairly rare at commercial filling stations, even in Europe, but common in Germany, where it qualifies for tax breaks. As the EU phases in renewable-fuel laws, the proportion of bio to petrodiesel will increase.) Thus, diesels can actually be the most environmentally and socially friendly engines: they can preserve open space by helping farmers to stay in business, divert revenues from terror-supporting nations and businesses, and, because the fuel can be produced locally with very little energy input, producing and distributing biodiesel requires less fuel (oil brought in from the Middle East must be shipped by boat and refined - both steps require quite a bit of fuel).

The Liberty isn't given 100% biodiesel at the factory because, Chrysler's Max Gates told us, the fuel is still uncommon and not standardized in the US. "We are working with standards writing groups to develop standards for B20 - 20 percent biodiesel - so that we can endorse use of that fuel...B100 [100% biodiesel] - while it may be used by a few selective individuals - is not really productive at this point, since there are not enough supplies of the fuel to provide for much of the nation's diesel fleet. Better to mix that fuel with conventional diesel and stretch its benefits across more of the country."

If you would like to read the entire review, click below: (the section on the diesel engine option is about half way down the page)



Sent: 4/13/2005 12:54 PM

I found some specific info on a diesel conversion at http://www.fostertruck.com/cummins/index.html

Here is the total cost of the conversion:

total cost

Engine, tranny, $ 1,500.00**

Exh brake, $ 800.00

Exhaust, $ 345.00

Rear axle Cover, $ 300.00

Cross members/mounts, $ 250.00

Drive line, $ 600.00

Radiator, $ 395.00

Fan/parts, $ 320.00

Intercooler, $ 400.00

Gauges, $ 171.37
Total: $ 5,081.37

**I got this engine and tranny from a wreck I bought at auction. I have attached the link for the auction company. I watched this site, signed up ($100) and made a few trips to the auctions. I watched a few wrecks go for all different prices depending on who wanted what and the condition of the vehicle. I finally got mine, it was a complete total, I mean really bad. The only thing left was the engine, tranny and rear axle. It was perfect for what I needed.   There are a lot of guys out there that buy Rams and rebuild the for sale, this drives the price up a little. It just takes patience and a little work to find what you want. Most wrecks go for around $3000-$5000. I was just there when a one came through that nobody wanted. The harder I work, the luckier I get!

Here is a fuel mileage chart for the conversion:

Acum Miles    Miles     Gallons   mpg/tank   Running average mpg
223.6     223.6  11.9   18.81           18.81
469.5     244.4   28.8    8.48           11.54
1097.8    628.3   50.3   12.48           12.06
1973.5    875.8   55.9   15.67           13.43
2735.5    762      43.1   17.7           14.4
3497.5    762      55.2   13.8           14.26
4197.5    700      50.5   13.87           14.2
4930.5    733      57           12.86           13.98

This spreadsheet is from my last trip to Cabo San Lucas from Seattle. Combined weight of 17,000+lbs. Pretty darn good I'd say!  Better than my old gaspot mileage of 7.6mpg for the same trip but only 13,000lbs.  Twice the mileage, 4,000lbs more, twice the horsepower, amazing but true! I love this engine!


Sent: 4/8/2005 12:32 PM

From a performance standpoint, the Hemi would be a better match against the Cummins than a 360 would be. From a fuel economy, towing, dependability, and resale value standpoint, it is clear to see which engine stands out from the rest.

It sounds like you have yourself a very nice truck, that you will be enjoying for a very long time!


Sent: 4/8/2005 11:40 AM

I don't think that the hemi will be a big  problem for the Cummings.  I drove a hemi powered ram and wasn't all that impressed, its fast but it has half the torque of the Cummins and it develops most of  it at 5,000 rpm's. Not good for towing. With 2, 30' trailers full of wood working equipment I need low end torque. 610ft/lbs @ 1400 rpm's should do.


Sent: 4/7/2005 9:03 PM

Great to hear some positive comments on a diesel engine!

A buddy of mine is the parts manager at a local Dodge dealership. About a year ago, there were two 2001 Dodge Ram, extended cab, (club cab) long beds,4x4s, on their lot. One had a 360 and the other a Cummins diesel (both engines stock). Knowing that I have owned and like diesels, and that the trucks were identical with exception to the engines and the color, he wanted me to test drive both trucks.
I took both trucks down the street a few blocks to the highway entrance ramp, starting with the 360 powered truck. At the top of the ramp, I floored the gas engine and merged onto the highway at a little over 65 mph. I then took the Cummins powered truck and did the same thing, only this time I lifted off the throttle and jumped on the brakes at 90 mph, near the bottom of the ramp, for fear of rear-ending a car while attempting to merge.  That truck would haul in more ways than one!

I have yet to drive a Hemi powered Ram, but my buddy said that they will give a Cummins a run for their money....


Sent: 4/7/2005 5:32 PM

I recently purchased a Dodge Ram 2500 with the Cummings 600 Diesel, I cant believe the gas mileage  ( I know a truck takes less to push than a motor home) but I can get almost 19 mpg highway and about 15-16.5 city according to the computer. This is a great improvement over my last truck an 02 Ram 2500 with a 360, I don't think I could get 14 highway going downhill with the wind to my back. It was a gas hog!!    Beside the fact that the Cummins has 325hp and 610Ft/lbs of torque as opposed to 245hp and 380ft/lbs with my 02 360. All that torque can make for some good burn outs! (only did that a few times, couldn't help it.)  And its the quietest diesel I've ever heard and its not just sound isolation, the motor is designed to run quieter. My brother had one in the early 90s and you couldn't  hear yourself think while in or around the truck.   I couldn't drive with an older diesel siting right next to me. That would be the biggest  problem for me.
Just commenting on how I like the Cummings motor,


Sent: 4/3/2005 2:17 PM

I was referring to doing a swap from the 727 to the A518 behind the factory gas engine.

MSN Member

Sent: 4/2/2005 4:58 PM

     If you were going to swap a 440 for a 5.9 Cummins you would have to use the A618, this is the correct application for the Diesel pick-up.  My Ram has this combo and it works very well.  I haven't (thank goodness) had any major problems with either the trans or the motor so I'm overall very pleased with this package.  The Duramax Diesel and the Allison 6 speed auto tranny offered by Chevy is also a great combo.  I just wish I could have gotten that Allison in my Dodge.
     I hate to say it again, but I still don't see anyone getting 14 mpg out of the 5.9 Cummins and A618 in a Winne.  A Winne has all of the aerodynamics of a sheet of plywood lashed on the front of a pick-up.  I only get about 13.5 to 14.4 mpg per tank local driving, and about 17 mpg on long trips not towing.  My truck is a 2002 Dodge Ram 2500 5.9 liter, 24 valve Cummins, 4x4, quad cab, short bed.  And diesel is $2.40 a gallon compared to $2.09 for gas here in PA right now.  It cost me $65 yesterday to fill my pick-up.


Sent: 3/31/2005 11:19 AM

My 727 is 33 years old, 96k miles, the original torque converter, tranny and engine.  never rebuilt, not worn out yet.  I don't plan to change a design that is so durable; So when mine wears out, I will rebuild and reinstall.

The 727 didn't come with an overdrive, though you could get an aux. transmission, which replaced the 727 tail-housing and output shaft. It also required changes to the drive shaft, and if your RV had the transmission mounted parking brake, I believe it left you without a parking brake.


Sent: 3/31/2005 10:55 AM

This thread was more for general interest, but switching to an overdrive transmission did catch my attention....

Torque converters, its 27 years old 45,000 miles, worth a swap???  do they make a 727 transmission with an overdrive???  thanks again for the input..


Sent: 3/30/2005 9:04 PM

And in response to the 12-14 MPG,

Time will tell, but I think I can get the 318 to at least 13mpg with the fuel injection and the proper cam timing, etc. It's a fun project....

I'm not quite sure when it will all be finished though, but happily I say it will be soon! (of course, the rest of the coach is screaming for stuff, too!)

Remembering My 72 D20RG Brave "Smurfbago" The old girl never let me down, and she's still on the road today. quick! get out the Camera... I spotted another junkyard full of Winnies...


Sent: 3/30/2005 6:51 PM

Whoa!  Correction to my first post!  The A518 will only bolt up to small block applications (318,360)

You can purchase an adapter, but they are expensive, so this would have to be considered in the overall cost. I checked the price of an adapter for a six bolt crank is $549 and $639 for an eight bolt crank. This info is from www.transmissioncenter.net

I also found this chart at www.dodgeram.org

Note the GCVW (Gross combined vehicle weight) rating of the A518 is 14,000lbs

I am neither for or against swapping to a different transmission, I just wanted to pass this info along so it would be available to those who may be considering it.

Automatic, 4-Speed Overdrive Gear Ratios
Transmission    42RH       46RH (A518)    47RH (A618)
1st Gear            2.74       2.45            2.45
2nd Gear            1.54       1.45            1.45
3rd Gear            1.00       1.00            1.00
4th Gear            0.69       0.69            0.69
R Gear            2.21       2.21            2.21
Torque Converter
Diameter    273 mm
(10.75 in.)    273 mm
(10.75 in.)    310 mm
(12.2 in.)
Input Torque
Rating (ft-lb)    NA             NA            450
GCVW (lb)            7,800    14,000    19,000
Application    V6 2WD   

V6 4WD, V8
V10, Diesel