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Discussion Starter #1
Hello all I am starting a diesel conversion. I would like to know if anyone has any advice or experience doing similar conversions. I am using a 6.2 chevy diesel now but when funds build again a 4bt will follow. I am slightly concerned with adapting the ecm and harness to a one wire engine. Any help is appreciated. :D
 

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I kinda have a soft spot for such an underdog diesel, but why go thru two diesel swaps and go thru the aggravation, cost and time. I'd say go for the 4BT and be done with it. If you already have the 6.2, I'd suggest selling it to help finance the purchase of a 4BT

It's possible to drop in a 6.2 diesel into a Dakota, but personally my choice would be for the 4BT, as the Cummins is a far more durable engine and has far more options available for it. The 6.2 was a very common diesel in it's time, and some parts may still be available, but there aren't very many performance options and the durability has been questionable.

The 6.2 has had some weaknesses. The injector pump isn't as dependable. It is also a glow plug engine. The controller can sometimes fail making cold weather starts next to impossible.

I wouldn't worry about running an ECM with a diesel. You'll also need to determine what transmission you will run with the engine. Some newer autos were computer controlled, some aren't. I'd go with a hydraulic controlled auto or manual. That way you can be computer free.

Ed
 

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Discussion Starter #3
All good points RXT. I am only going with the 6.2 because it runs strong and I need to convert the transmission to a Chevy bolt pattern. Currently the 4bt I plan install will use a Chevy normal pattern. In the swap I will be installing a 700r4 diesel transmission with an NP208 transfer case. My front axle requires a passenger drop t-case and the 700r4 is easier to adapt to the 4bt. I would stay dodge but I have already blown one 42rh and I don't like using an adapter to mate my NP208 to an NP241 Jeep tail housing.

Speaking of 4bts I am not sure I like E-Baying one. Does anyone know of a good source of small diesels that doesn't require Paypal.
 

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What I don't understand is why do you particularly want to convert to a Chevy bolt pattern? To eventually run a 700R4 with the 4BT later??

If you don't already have the 4BT, or a tranny to go with it, there are a world of transmissions you could use. You can run anything from a 700R4, (and a variety of other Chevy transmissions) or a Dodge 46RH. (Which is substantially better than a 42RH and certainly not recommended behind a Cummins) Theres even a few Ford autos that were found behind the 4BT. You could even mount a couple of different Allison models. The 6.2 should already be ready to mount a Chevy automatic. Many diesels are equipped with an adapter plate and the 6.2 is no exception. In the case of the Cummins, these engines were found in a wide variety of applications and in front of many different transmissions, so there are a variety of adapter plates. The 6.2 was also used in a limited number of applications, so there are fewer available adapter plates for other makes of transmissions. The only thing I'm thinking that you're trying to do is, buy one transmission that can be used behind both engines, so that you can start with a 6.2, but then swap later to a 4BT without having to swap transmissions. Although I'd be partial to using a Dodge transmission, it's understandable why you might consider a 700R4, but heres the thing. The 700R4 as commonly available as it is, and there are a few performance upgrades available for it, I still wouldn't discount the Dodge 46RH as an option. The aftermarket has thoroughly supported Dodge autos, especially those used behind 6BTs which have been significantly turned up. A 46RH can be built to live behind some serious power from a very healthy Cummins turbo diesel, levels impossible for the 6.2 to ever attain. The 700R4 is supported by the aftermarket too, but not necessarily for the diesel world. For that, they recommend going to the Allison 1000. (Which can also fit behind the Cummins 4BT/6BT)

So why would you need to use a Jeep NP241 tail housing???

Ed
 

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Discussion Starter #5
I have a passenger side drop t-case. The primary reason I am using the 700r4 is the overdrive and the ability to use the Chevy t-case. The 6.2 does not use an adapter but in fact is drilled to take any Chevy 90 degree bell housing. If I find a Chevy adapter plate 4bt it will directly replace the 6.2. The final point of the 6.2 is MPG, the 4bt will deliver about the same MPG stock as a 6.2. I expect 20-25 from the 6.2 and 22-27 from the 4bt. I plan to go the 4bt route but $3000 is more than pocket change to cough up. The first step is diesel the second is 4bt. The 700r4 tranny will render good MPG but is also well supported aftermarket wise. The 46RH is a great tranny but hard to find in the passenger drop configuration. In Nuevo Mexico we have to pinch pennies.
 

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My guess here is you already have a 6.2, 700R4 and a transfer case with passenger side drop. Because that would be the only way you could justify such a swap, only to do it again once you spend the money to have a 4BT available, because if you don't, you'll be spending a bunch of money to buy a 6.2 & 700R4, only to pay out an additional chunk of change to purchase a 4BT. It doesn't sound like the best way to pinch those pennies, hombre.

But it's your money and your truck....

Ok, going back to the original post. The advice I'd give, other than not to do it, is, you won't need the ECM. All you need to do is wire in the shut off solenoid into the ignition. The old 6.2's used to have a sending unit for the glow plug "wait" light. This shouldn't be difficult to wire in and you can use a simple LED for the wait light. The main difficulties will be fabricating engine mounts and an accessory drive for the power steering, alternator and a/c pump. You'll need the 6.2's hyro-boost pump to create the vacuum for the master cylinder which provides the power brakes. The transmission will need it's own mount and you shouldn't have a problem mounting the transfer case to the tail shaft, but you will need to fab up the linkages to the t-case shifter. You mention that you'll be using a transfer case with a passenger side drop. I'm also assuming that you'll be doing a solid axle swap too. You'll, of course, need a front axle with a passenger side pumpkin. If you weren't planning to swap out the front axle, the stock axle assembly won't be up to supporting the weight of either the 6.2 or the 4BT and it probably won't survive long behind the torque of the 4BT.

The factory front axle is a driver's side pumpkin. You won't be able to run the front driveshaft from a passenger side transfer case to a driver's side axle pumpkin. Further, the factory axle assembly is supported by a set of mounts which also doubles as engine mounts too. If you have to fabricate up a set of engine mounts to carry a 6.2, you'll have to fabricate the mounts which support the front axle assembly.

Finally, the swap may not be legal. In general, according to federal law, it is not legal to swap in an older engine into a newer vehicle. The 6.2 was produced between 1982 to 1993, so unless you happen to own an 87 to 93 Dakota, and the engine happens to be newer, the swap won't be legal. Now it's more than likely, no one is going to actually check, and there could be some exceptions in your state laws, but if your state requires passing smog tests, or pass state safety inspections, and some official has an opportunity to raise the hood of your truck, there is a chance of discovery and you may have some problems.

Ed
 

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Discussion Starter #7
All great points Ed. Let me start with pictures of my truck. The build is available at http://www.pirate4x4.com/forum/dodge/1033981-sas-dakota-2wd.html You can see that the SAS was completed about two years ago. The use of full size Chevy axles make a passenger side drop required. The front suspension was redesigned with the 454 duty leaf springs from the Chevy. I was collecting parts for a 4bt swap and found that the Chevy tranny costs just as much as a running low mileage 6.2 parts truck. I was going to save longer to buy the 4bt but then a blew the 3.9 v6 engine mounts, split a radiator, and cracked a cylinder head. Not to mention the SAS proved to much for my old 42rh which was dying anyway.

I figured roll with the 6.2 until the 4bt funding is there. The conversion to diesel is very involved. Changing to a 4bt from a 6.2 requires a few mount modifications. No big deal considering the trouble I have already been through. You are right though the ECM is really not necessary. I was planning on grounding pin 51 to hot wire the fuel pump and coil wires to the ignition. I modified the fuel pump to reduce the pressure for this duty. A TBI Chevy pump fits the Dodge canister but only produces 10-15 psi at the required GPM.

I am lucky in that Rio Rancho does not test emissions. I have a loop hole though because the Dakota is a 1993 and they really can't prove the engine is any older than 1982-1995. The 6.5 is mechanical in 1995.

I do find it interesting that most people hate the 6.2. The engine is mildly sensitive and requires a loving touch. It is by no means a Duramax, Powerstroke, or Cummins. But it gets better mpg than some Japanese four-bangers out there. I was inspired by the Australians to do the swap before I could afford the 4bt. They fight over 6.2s to put in Rovers and Cruisers. Cummins spoiled the USA I think LOL.
 

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It looks like you got it all figured out :)

I do find it interesting that most people hate the 6.2
The 6.2 will always be the redheaded stepchild of diesels. It has never been well liked and it certainly pales in comparison to the current crop of modern turbo diesels. I think that when it was introduced, GM was still reeling from the fiasco of it's first attempts to introduce a diesel back in the late 70s with the 5.7 diesel.

For those who aren't in the know, during the late 70s, GM decided to modify the Olds 350 to run on diesel, to take advantage of diesel's inherent fuel economy advantage. But there were problems. The engine couldn't keep head gaskets and there were numerous warranty claims against GM. In the end, GM would replace the diesel engines at great cost with gas engines. The reputation of all diesels would be affected and it would be quite some time before the public gave diesel another opportunity.

With that fiasco behind them, GM started with an entirely clean sheet of paper for it's next diesel attempt. At the time, Detroit Diesel was a division of GM. Detroit would design the 6.2 with an entirely new block, specifically for diesel use (It does not share components or design features with any other GM V8) This engine would be far more dependable. GM ended up producing most of the light diesels during the 80s, many going to Uncle Sam to power the M1008 and M1009 CUCV. In the civilian markets, they were introduced in Silverados, Blazers, Suburbans, and Vandura vans. The 6.2 would also power the earlier variants of the Humvee.

Although the 6.2 was a better engine design, the engine was considered underpowered for it's displacement. Many opted to buy or swap the proven Chevy 350 as it actually made more horsepower and torque than the 6.2 could. Gale Banks would make a fortune selling turbos for the 6.2 which really woke it up

GM eventually got some competition when Ford decided to enter the diesel market with it's own International built 6.9 I.D.I. To counter, GM increased the displacement of the 6.2 and made some design improvements when it introduced the 6.5, but it wasn't long that GM sold off Detroit Diesel to Damiler-Chrysler, while the 6.2/6.5 design was sold to a new manufacturer known as General Engine Manufacture (GEM, a division of Hummer) which continued to supply diesels to GM. But by then, GM lost the diesel market to Ford and Dodge, until it reentered with the Duramax.

My soft spot for the 6.2 isn't that it's a great engine. In fact by all accounts it's a rather mediocre engine. Other than adding a turbo which still won't get it to match any of the current modern diesels, there isn't much that the engine offers in the way of performance. The only good thing this engine was capable of was providing good fuel economy. I just like it because it's certainly different, it's old school, it's obsolete.

You got a good build on your Dakota and seeing the truck answers many of my questions regarding your swap. I'm getting ready to do a solid axle swap on my own Dakota. I already have the parts I need. In my case, I'm using a Dana 44 narrow track out of a Wagoneer, driver's side drop. I'm not doing the diesel swap at this time. I'm keeping the 5.2 Magnum currently in it. Later I'll look for a 4BT. I already did a Cummins swap to my 83 Ramcharger. In that case I used a 6BT and dropped in a Dana 60/70 and divorced 205. That project is on hold indefinately until I'm finished with my Dakota. I'm a regular at Ramchargercentral.com
You can see my Dakota build here at; http://ramchargercentral.com/mopar-trucks/dakota-club-cab-to-quad-cab/

I've seen your truck while I was researching my SAS. You seem to have a novel solution for the front springs. You mounted the shackles at the front just like Jeep did with the CJ series and the leaf sprung Wrangler. The front mounted shackles were believed to contribute to a rough ride. How does yours ride with that configuration?? I'm considering the idea myself

Sincerely Ed
 

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Discussion Starter #9 (Edited)
Hello Ed, spot on with the article. I understand most people have mixed emotions about the 6.2. I love the idea of a lifted truck getting over 20 mpg. Like I said the 6.2 swap is just until I save up for the 4bt. Maybe in the future that build will be here as well.

As for the bump steer ride. The shackle up front (in my opinion) is the only feasible way to go. The frame just dips to low in the rear were any respectable leaf would mount. I have a theory about jeeps handling poorly. The shackle in front does create strange handling but not unpleasant effects. Jeeps are just so dang light that the bumping jars the body. The Dakota has 454 duty leafs with a v6 weight and handles better than an IFS 3/4 ton Chevy. With the diesel it will smooth out more.

Crazy4x4rt did an SAS using rear shackle and I think that is just too much lift (it works well for him though). I simply don't need 12+ inches of lift. I wanted 8-10". Shackle front is the most logical way. My Dakota is a toy really so road manners mean little to me. Off road the shackle forward actually climbs and digs better. The design forces the axle into the obstacle instead of away from it. That's why old Jeeps did so well. I also tucked the shackles in behind the bumper for protection. The shackles are OEM ford 3/4 from Dorman and will take a good hit without damage.
 

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At the risk of going way off topic, I agree with you, definitely! The frame does has a significant dip and I was kind of concerned about how much I'd have to drop the hangers if I mounted them at the front with the shackle at the rear. I seen yours and I was thinking that, hmm, that solves the difference between the front and rear, but hows that thing gonna ride?

The general consensus about Jeeps with front shackles has been that they tend to ride rougher because of the location of the shackle being at the front of the spring. As it goes, a leaf spring with a bit of arch will lengthen as it's compressed. With the shackle mounted at the rear, the axle will move slightly towards the rear and "with" the direction of the impact. But with a front mounted shackle, the axle tends to move "against" the direction of impact, thus transmitting more of a jarring effect. But as you say, that is also on a lighter chassis. There might be another dynamic involved and one I was thinking about, and which might just apply in your case. If the spring isn't level, another-words, the spring eye at the front is higher from the ground than the spring eye at the rear is, then a front mounted shackle may be less likely to transmit much of the jarring effect into the chassis. The angle of the spring could potentially cancel the forward motion of the spring. This is because the angle of the spring would change the direction of axle movement, into a slightly forward and upward direction. I'd be curious to see if perhaps your springs are angled in relation to the ground.

Anyway, I was curious about your results. In my case, I'm running a Wagoneer axle. I also have the springs that came with the axle. The Wagoneer axle uses a spring-under-axle configuration. So in my case, if I keep the springs, I think I can afford the extra length needed to run a front hanger/rear shackle arrangement with that deep frame dip. I do want a bit of lift, enough to run 38s

Ed
 

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Discussion Starter #11
Ed you may be on to something but I can tell you 33" tires rub with the shackle setup I have. I would imagine 38"s would not fit well. A few more inches and probably. I recommend doing the lift that feels best for you. I like the look and function of the shackle forward. I would be interested in seeing your swap. Let me know if I can help with the details.
 

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Yeah, I'm kinda risking the possibility that my tires may rub on the springs when the swap is complete. The one thing no one can argue is that Dana axles do have some seriously tight turning knuckles on them. I'm not sure if every Dana axle has adjustable steering stops on them. I remember seeing them on my old F150 that I had over 20yrs ago, and the Dana 60 currently under my Ramcharger has them now. But I didn't notice them on the Waggy axle. I'm gonna guess that they are there. I'll probably adjust them out to prevent tire rub. I will lose some turning radius, but so long as it still has a reasonable turning radius and I'm not having to do three point-turns in intersections, I think it will be good enough and the front u-joints may feel a bit happier too. We will see.

As a matter of fact I do have a couple of questions... What did you do about brake lines? I'm wondering if I can still use the rubber lines to the calipers. I'm guessing the Wagoneer calipers are different enough that I may have to build custom lines to mount from the Dodge hard line to the Jeep caliper. ????
And what did you do for a pitman arm? My research suggests that the Grand Cherokee pitman arm will fit on the sector shaft of the Dakota's steering box. The Dak's pitman arm won't work.

Thought's??

Thanks sincerely Ed
 

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Discussion Starter #13
Good questions. As far as brake lines in my case the Chevy mounting was completely different than the Dakota. I went to a local hydraulic hose shop and had the make me some. Most cities have shops that fabricate brake lines. The idea is get a line for Dakota on top and Chevy on bottom. In either case you will find the IFS style lines are not any were near long enough. I had to get 18" lines compared to stock 6".

My truck started life as a 2wd. It was equipped with a rack and pinion. I found that the IFS Chevy gear box fit well and I grafted it to the frame. I am not much help with pitman arms. I would recommend measuring the Grand Cherokee arm compared to Dakota gear box shaft. If it is the same diameter with equivalent tooth count you are good.

Second note it would be wise to upgrade your axles before swapping them in. Dana 44s only live a short time when used with 38"s. If you never go off road they will last a few years before things turn evil. Off road it all depends on how hard you try. I have seen people wedge a rock and grenade 44s on command. Hardened shafts, upgraded ball joints, and possibly tube stiffeners will all help.
 

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Thanks for the tips, It's greatly appreciated. Yeah I will be rebuilding the Dana 44. I'm keeping the rear axle already in the Dakota. In fact I'm redoing both. The Wag axle has some pretty tall gears in them, and it doesn't match the rear. So I'll be swapping gears in both, putting in new diffs (Don't know yet what I want in the way of lockers or limited slips)

I live in Florida and we don't have a rock problem here. There simply aren't any. We tend to have to deal with mud and water. On a Dana 44, 38s aren't as much of a problem in mud as they could be on rocks. So long as you aren't spinning the tires and transitioning from a soft surface to a hard surface. It's also hard to say how well any axle will hold up. Years ago I used to break a Dana 44 regularly with just 33s on a 78 F150 I used to own. But another Dana 44 held up fine with 38s under a 77 Bronco, I also used to own. So we will see. Of course I haven't bought the tires yet, but if I get a great deal on a set of tires that aren't 38s, I may not pass them up. (My target size range is between 34s to 38s and I'm actually leaning towards a radial)

Once again thanks for the tips
Ed
 

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Discussion Starter #15
I have an update on the swap. The 3.9 is out and now the 6.2 is sitting in the engine compartment. The engine is not bolted in but ready for fabrication. Hopefully two more weekends and I will post a video of the truck running. The 6.2 is not nearly as big as I would have expected. It fits with room to spare in the engine compartment.
 

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Discussion Starter #17
Okay I have the mounts in and the engine now has a place to live. I hope to have the engine in place by tomorrow and connected to the tranny.
 

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So whats the word with your engine swap?? I have an update too. My truck will be going in soon for a front axle swap. I also found a V10 47RE with transfer case at the local junk yard. Already started pulling it, hopefully I'll have it in my possession soon. I'll be looking for a 4BT next.

Ed
 

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Discussion Starter #19
Wow a v10 is ambitious. Good luck wifh that. I have the motor in and bolted down. I only lack a few electrical conections and installing a new positive battery cable.
 

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Nah! I'm just getting the tranny and transfer case off the motor. The V10 and Cummins shares the same bell housing. After that, I will look for a 4BT Cummins and bolt it to the tranny/t-case.

Ed
 
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