Project 1tonfun

[BWJensen]

Hi Everyone!

I tried this thread in the conversion forum and 4 days and 100 views later, 0 replies. Brought it here hoping for better results.

I've started a new project and am seriously considering a diesel conversion.

Here's what I've got, so far. A 1979 Dodge W200, 440, TF727, NP203, DANA 60's. The truck has been completely disassembled to the frame.

I'm now starting to do research on a Cummins diesel conversion. What I want for a conversion is a GEN 1 Cummins, auto, a transfer case with the lower gearing , and A/C.

So, what I'm looking for is input on what I should look for in a donor truck and why.

Thanks for any input.

Maddog

 

[1stgen4evr]

You really have not said where you want to wind up other than one ton fun. Lot of territory there. A w200 is a 3/4 ton fwd so I guess you are looking for a dually with a Cummins to bring the project to 'one ton'. If it is going to be something of a trail ride, you will be changing the ratios from what would be standard so look for something with a Cummins and go from there. Nothing special about the Dana 70 rear. You can sub anything you want as to ratio and manufacturer. The Cummins powered trucks have a heavier 60 than what you truck came with so you will need a Cummins rated Dana 60. If a make it or break it trail ride is what you are into, contact Michael Miller. He may not be the resident expert but he knows his stuff on the Dodge trail truck.



James

 

[MMiller]

Uh oh, James is refering to me again... ... . thats bound to get me into trouble.



I'm a little confused in what you are wanting. I see you want a first gen with auto and transfer case with lower gearing. Are you refering to wanting a t-case with a lower then 1. 9:1 ratio in the stock 205? If you find a first gen 4x4/auto, I'd look for one 91. 5 and newer as they came with an auto with OD. All first gen 4x4 came with 205. Now, your front dana 60 is the same as the front 60's that came in the diesel trucks. Nothing differnt there, but you are going to have to use a transfer case with a passenger side drop. Anything with new t-cases with lower low side, are all drivers side drop. Now, there is available for 205 cases, a new low gear set, if thats what you are after.



What are you planning on doing with the truck? Daily driver, offroader, truck pulling? This will guide us in drivetrain selection. The dana 60 rear will hold up if you don't use the torque of the cummins(ie no heavy towing, NO truck pulling, NO offroading), a dana 70 is a good choice(thats what dodge used in the first gens), and if your going to be turning lots of power, and truck pulling, then a dana 80 is recommended.



I'm in the process of setting a 90 CTD for offroad duty. Going with 4. 10s, detroit lockers, 38" tires. For now I'm going to run the factory 727/205. I'm going to wheel it a while, and then decide what next. I'm thinking a 518 and a 203/205 doubler setup. That way I'd have od for the highway, and then 1. 9 low for mud and mild trails, and almost a 4:1 ratio in the t-cases for rocks/technical trail sections.



Let us know, is it going to be a pavement pounder, racer, offroader, puller, etc, and I'll help more.



Michael

 

[BWJensen]

Thanks for the replies,

Okay, first a little geography. I live on the northern edge of the Black Hills of South Dakota. Where the HELL is that you ask? Good question. Maybe you've heard of a little motorcycle gathering called the Sturgis Motorcycle Rally. Well I live 20 miles from Sturgis. If you haven't heard of it, maybe you need to get that rock off your head. I'm sorry, seriously though, how about the Wyoming/South Dakota border. That's close enough.

As far as terrain. Outside my front door are 5000 acres of the Black Hills National Forest. You know Mt. Rushmore, Wind Cave, that place? Anyway, out my back door are the Great Plains of South Dakota. So terrain varies greatly, and changes with the seasons.

Time is not an issue with this build. When it's done, it's done. I'd rather take my time and do it right, than cobble it together like some rigs I've seen. Where I'm going to go with this thing AAA won't. It's gotta get me there and back.

As far as the build, let's call it a trail rig with an attitude for know, but that may change. Because the truck will also need the capacity to pull a 28' camper and 18' boat to whatever playground I'm heading to. I'm also an avid sportsman so any creature that crawls, slithers, swims or flies--it's got to get me to that place and back!

The mechanical side of it:

Motor-I'm looking a the Cummins for several reasons: Better fuel economy, more reliability, and better torque performance (not in that order).

727 trans-either rebuild with a RV shift kit and torque converter to handle the motor or I sure like the idea of a 4 speed auto for those 700 mi. round trips to pheasant or goose camp!

203 TC- the 2. 01:1 gearing blows! how about a Trey conversion from WMS? 3:1 low but not sooo low. I like the full time capabilities on an icy road.

Axles- rebuild with selectable lockers, regear for some bigger treads. What about a rear truss and torsion bars to handle the motor and lockers? Upgrade the drive flanges to 35 spline, perhaps Polyperformance? The rear is a 60HD which will have the axle shafts upgraded.

Suspension-A little lift, greasable shackle flip, some more flex.

Basically this is going to call for a frame off build. So here's where I started. Complete disassembly to see what I had to work with. And then start from there.

First thing all the sheetmetal has to go. Next, I'm going to start strengthening the frame.

I haven't been a member for long, but have really learned a lot from those of you willing to share lessons learned during your project builds and those that are willing to share their expertise. I'd really like to hear your thoughts as I work on this project.

MADDOG

 

[csutton7]

depending on what HP gains you're lookin' at a simple transmission kit won't get you far either---so it would be smart to look into viable upgrades from one of the transmission companies that are known on this site---



going to 35 spline axles is a good idea, but what about the ring and pinion set up--can they take the torque abuse and ujoints---I don't know how the 60HD stacks up against the 70, so maybe I'm being skeptical here, but I agree with MMiller that it would be wise to get a 70 or 80---especially if you up the HP/torque



ARB in the front is what I have and it's great--I'll be putting one in the rear here shortly--although with my old 70 rear I had a detroit in it and didn't find it to bad, but as you know they can get a little tricky in slickery conditions, so going selectable front and rear is a good idea in my book---I ran the ARB in the 60 front for 4 yrs before I broke a small part in it--that numerous sled pulls that it endured, so I'm sold on it--



sounds like a fun project and if you could find a donor diesel truck it would make life simpler---good luck---chris

 

[MMiller]

The dana 60 rear 35 spline axles will hold the torque of the cummins in your application, but I fear the smaller r&p will not like it. I think in the rear you would be money ahead to run a dana 70 rear. For what you are doing, that will live, and you can run your 35 spline axles.



If I were doing what you are wanting, I would step up to an OD auto, even consider going to a 47hr, which will give you OD and a lockup convertor. If your planning on running miles, tow, I'd do it. It'll be some $$$ now, but it would be worth it. Even with say 3. 55 gears, and 35 inch tires, your 727 will be fine with a good convertor, but the cummins will be begging for an OD. You might even consider getting an exhaust brake for towing where you live, then you will HAVE to have a lockup convertor transmission. Remember when dodge put the cummins hooked to a 727, you only got 3. 07 gears, so the truck could run down the highway alright.



Choose your transmission, then choose the rear gears. *I* prefer the 3. 55's and I run a 305/70R16 mud tire, and tow heavy. I'd probably rething gears, if I was running taller tires.



I suppose the 203 will be OK, if you really want full time 4x4. You need to think about cornering with a much heavier engine up front. My dads old 77(400) and my 75(440) would scrub and bind when cornering, the 77 is long since gone, and my 75 is running a part time kit, and lock out hubs. To each his own there. I've never complained about locking my 93 in, with a tight LS on the ice. It's easier for me to keep driveline vibrations down, when not all of its turning all the time.



Just my $. 02. Take it or leave it. It sounds like you have a heck of a project going on there. Maybe sometime I'll have to load up my offroader and come up and see where you live. Sounds like some beautiful country, I've never been up there. Seen lots of pictures of Sturgis though!



Michael

 

[MMiller]

The other thing to remember, the cummins will take differnt gears in the t-case, then a small block or big block. What may be too tall for a gasser, the cummins will just grunt through. I used to take my 93 off road, and I'd let it idle up to obsticles, and it would either crawl over, or spin all four tires... ... . at idle... ..... with no throttle input. My 440 won't do it at idle, but it will off idle. The 440 has 410s and the my 93 has 355s.



I'll shut up for now, probably overloading you with my opinions. Only you really know what you want to end up with, good luck.



Michael

 

[BWJensen]

Project: 1tonfun

Thanks guys,

The axles have 4. 88 DANA gears in them with ARB lockers. And 37" MTR's. This was my initial setup when I was looking to rebuild the 440.

THEN, one day I came across this site and started reading about gas to diesel conversions! Well, to say the least that threw a monkeywrench into the mix.

So back to the question. To find the motor/ od auto transmission / 205 transfer case (a doubler isn't out of the question!) What do I want to look for in a donor truck?

MADOOG



PS, Michael there is always a cold keg in the doghouse fridge! And until you've been to Sturgis, you ain't seen nothing! :--)

 

[1stgen4evr]

Rode through Sturgis and Hill. I saw it all. Including a lizard with NOTHING but chaps. Jeepers creepers.



James



Oh and about the trucks- - - figured some of the guys would jump in on the questions.



Edit: Heck of a note to have the 1001st post about Sturgis and not trucks. But for sure, if you have been there, you don't forget.

 

[MMiller]

I'd look for a first gen 4x4, myself would look for a 91. 5-93. These trucks came with factory intercooler, and OD automatic transmission. When you find a complete truck, then you will end up with dana 60 front/ 70 rear already, with either a 3. 55 or 4. 10 ratio. Unless you pile up OD units, or run enormus tires, the 4. 88's are going to be very steep.



Then you will have a big block, 727/203, and one ton 4. 88 gears to stuff in a ramcharger, shortbed truck, or even a jeep or scout. Then you'll have a dedicated offroad truck!



Shucks, now I'm going to get you worried about your 'next' project. :-laf



Michael

 

[BWJensen]

Project: 1tonfun

Short of buying a FSM for a 91. 5-93. What is this od transmission called, and where can I find the gearing raios ? Sorry for the dumbass newbie questions, I can talk big block gas all day long.

Maddog

 

[R C Cola]

Conversion ?

How tough do you want? I have an acquaintance in Ca who bought an older dodge PowerWagon went thru it, made like new and put a 93 Cummins

w/intercooler and backed it up with HD Alison transmission w/overdrive for the hiway. He drives from Ca to Idaho at freeway speed to camp, then has the best gruntin and huntin 4x in the area. R C

 

[MMiller]

First gens came with 518's which are just a 727 with an OD unit on the back. They are good units, especially after spending some coin on a good, tight convertor.



A good upgrade would be a 47rh, which is a 518 with a lockup convertor, and its hydralically controlled, meaning no computer controls, just have to wire up a switch to control convertor lockup. A few fellows here have done this upgrade on a first genner and they can step in.



Are you wanting the ratios of the transmission. They are the same as a 727, I don't know the OD ratio.



Michael

 

[BushWakr - RIP]

I believe that DC "beefed up" the 727 a bit when they went with the Cummins engine. .

The OD is the weak link in this chain... . you should consider (as mentioned) having the/A transmission worked over to take the abuse you're going to put it thru. Once you've done that I wouldn't take any other transfer case than the NP205... is all iron as you probably know, it's all gear drive again as you likely know and they are worth the cost to have one re&re'd if needed.

The axle upgrade to 35 spline is an excellent suggestion... (I think ours are what... 32 spline) stock.

We have/do have some guys pushing over 500 RWHP thru the stock diff's and they are holding to gether but they don't go off road with weight in them... . just lunatic dyno and road applications.....



Also, as mentioned get a 91. 5 - 93 model year... they have the intercooler and even if you have to replace it, you won't have to fiddle with making one fit into an earlier truck. As well, the earlier engines were more prone to head cracking when "worked" very hard. They have larger injector bodies and there was not quite enough 'meat' betwee the valve seats and injector bores... . they get real hot and they end up cracking more often than the later model 1st Gen's do.



Good luck with the project... . I KNOW the guy's in here will help all they can... .



pb... .

 

[BWJensen]

Project: 1tonfun

OK, after a few days of research I think I have brain damage, no wait, MORE brain damage.

First question , I've found a site where they give you the tech to covert a TF727 to a 518. http://www.transmissioncenter.net/alto_3.htm, is this a viable option or no? If it is, can a nonlockup converter be upgraded to a lockup converter?

Then, I'm having trouble with this axle ratio gearing. All the info. and conversion charts I have found all give me the same answer. To run 37" tires the axle should be geared at 4. 88. What am I missing?

Check this out:

Sample truck: https://www.turbodieselregister.com/forums/showthread.php?t=150364. Observe the specs in the signature. Convert the tire size, feed it into the MPH to RPM calculator, don't forget to multiply the gear ratio by . 69 (this is the OD ratio of a 518, someone correct this if I'm wrong) and tell me if this is acceptable.

Calculators: http://thedieselgarage.com/projects/tirecalc/tirecalc.htm

I have to go get a beer and mumble to myself for awhile.



as always , thanks

MADDOG

 

[TKingsbury]

Hey Maddog, this is the guy you called from Pirate about the door panels. Small world huh? I checked your gearing on the calculator, and 4. 88 would put you pretty much back to stock gearing. That would give you 65mph @ 2,000 rpm. That is assuming you have true 37" tires, not just 37 on the sidewall. Find the tires you want and find out their true diameter before you commit to a gear. You may find that 4. 10s will work if the tire is actually a bit shorter.

As far as what truck to buy for a donor, I'm with MMiller. Find a 91. 5-93 4x4 auto and swap the whole mess in there, rear axle and all. I wouldn't worry about a lock-up converter either, lots of guys doing just fine without it. Just get a good converter and call her good.

Travis. .

 

[BWJensen]

Project: 1tonfun

Hey Travis,

Small world! Glad to here from you.

I remeasured the tires and they are 36. 8" an the button. So, unless someone else has some insight 4. 88 this is what I'm going with.

I also rechecked the specs on a DANA 60HD verses a DANA 70 and the only difference I've found is the ring gear diameter difference.

And now to find a 91. 5-93 CTD, AT, 4X4 for a donor. Anybody have one?

And what telltale signs of misuse and abuse should I be looking out for?

MADDOG

 

[csutton7]

low gears are needed in gassers due to their lack of torque---with the cummins there's so much torque you don't have to think along the line of gasser gears--chris

 

[BWJensen]

PROJECT: 1tonfun

The calculator I used is on a diesel website. Check post#15.

Maddog

 

[BWJensen]

Let's say I was toying with the idea of a manual transmission. What are my options? And pros & cons ? :-{}

MADDOG