Hi,

I am currently exploring the possibility of swapping a GM 6.2L diesel into my 1988 Dodge Dakota.

The information I have gathered is as follows:

• 6.2L Diesel Swap Simplicity
  • No engine computer; minimal electrical work required.
  • Existing Dakota fuel system is easily adaptable.
  • Transmission adapters for Chevrolet small block/big block/diesel engines exist to adapt 6.2L diesel to Chrysler transmissions.
    • Original transmission will have to be swapped to handle the torque of the 6.2L.
• Engine & Transmission Mounts
  • Physically mounting the engine to the Dakota is where information is lacking.
    • As seen in the video below, the original Chrysler LA mounts could be adapted to fit a 5.3L LS, but the LS mounts are different than the Chevrolet small block/big block/diesel engine mounts, yet very similar. An adapter plate from the older mounts to the LS mounts can be seen in the second video below.
  • I'd prefer to stick to Chrysler transmissions as they'll bolt directly to the stock mount configuration. GM transmissions would require additional modification.
• Engine Size
  • Radiator/fan clearance concerns.
    • The 6.2L is roughly the same size as a 360 or 318, so fitting it into the engine bay shouldn't be an issue, but the cooling system may need to be modified. An electric fan should be a viable solution if a belt-driven fan fails to work as this is a common solution for cooling systems in Dakotas with a 318 or 360 swap.
• Fuel Economy Improvement
  • It's no powerhouse, but considering the truck will be my daily driver, I am interested in the improved fuel economy offered by the 6.2L.
• Price
  • I am aware the 6.2L isn't the best diesel engine out there, but it is significantly cheaper than any alternative.

A 6.2L diesel conversion has been completed and proven to work as seen in the third video below.

So far, it appears the 6.2L diesel is the cheapest and simplest solution to swap a diesel engine into a Dakota. What are your thoughts? I'm not 100% sold on a 6.2L, and I still have plenty of other options to consider, but I wanted to throw out this idea first.


Thank you in advance!

5.3 LS Dakota Engine Swap

 

Not meaning to throw water on your plans, but here are a few suggestions and questions.....
1. the 87-90 front end is about 3.5 in. shorter then the 91-96
2. The motor mounts on a 87-91 3.9 are actually the same as the magnum.
3. IMO using the transmission that came behind the diesel is going to be much easier then adapting a chry. trans. to a gm motor. Not to mention the tq requirement ......
4. Is this 2wd or 4?
5. How do you plan to support the additonal weight?
6. IMO pretty much everything behind a 6.2 diesel needs to be 3/4-1 ton capacity. IE, trans, rear end, frame, suspension.
7. IMO it would probably be easier to take a chevy truck and cut it down to mount your dakota body and bed to that.
8. To make this into a daily driver is going to be expensive and labor intensive!
Good luck if you try it.

 

Not to mention the 6.2 is a BIG motor..... will it even FIT in the Dakota engine bay???

 

You're definitely not throwing water on my plans, I appreciate the input.

• My Dakota is 2WD.
• I haven't looked very closely into the weight situation yet, but I'm sure there's a solution. On another forum, someone suggested using a lift kit to compensate for suspension sag, but even so, I'd think the additional weight of a much heavier engine on the stock suspension would wear the suspension out.
• 6.2L diesels can be found in 1/2 ton and larger GM trucks starting from the 1982 model year, therefore 3/4 or 1 ton components should not be required.
  • If a Cummins 4BTA, a more common diesel engine swapped into Dakotas, was installed, 170HP/420lb-ft would require 3/4 or 1 ton components, but the 6.2L is nowhere close to those numbers.
  • 6.2L diesels are not overly powerful engines. A naturally aspirated 6.2L diesel makes 130HP/240lb-ft at the lowest end, only 5HP/45lb-ft more over the original 3.9L LA. When compared to a 3.9L Magnum (175HP/225lb-ft), the 6.2L diesel leads by 15lb-ft, but falls behind by 45HP, and when compared to a 5.2L Magnum (220HP/295lb-ft), the 6.2L falls behind in both horsepower and torque by 90HP/55lb-ft.
    • If Magnum swaps have been done without significant changes despite being much more powerful engines, I'd imagine a 6.2L could be done.

The third video in my original post shows that it will fit in 1991 and later models, with the only difference between those models and pre-1991 models being the length of the engine bay with height and width being identical. According to my service manual for 1988 Dakotas, the length of the engine bay from the firewall to the grille is 37.59" and the length of the 6.2L is 29.5" according to Diesel Hub. I'd imagine there should be enough room. Making sure the cooling system will fit is the next challenge, but an electric fan should provide enough clearance, similar to if a 318/360 swap was being done.


1988 Dodge Dakota Service Manual - 1988 Dodge Dakota Dimensions

1988 Dodge Dakota Service Manual - 1988 Dodge Dakota Dimensions

 

Well it looks like you have done quite a bit of research.......
Is there a reason you want to put the 6.2 in there?
I remember those motors, and they were dogs, as well as not being fuel efficient....
If your doing it to be different, hey I love to see it. after all, that is what hot rodding is all about.
But if its for being practicable, I dont see how it will be. Its going to be lots of work and expense.

I still think it would be easier and better to purchase a complete truck, modify as needed, and move your body and bed over to that frame.....

Look forward to seeing how it goes!!

 

Yeah, the normally aspirated 6.2 was not exactly a powerhouse..... could push the house off it's foundation, or pull a train uphill, but, there certainly wasn't anything even remotely resembling 'quick acceleration'..... In a truck that weighs a 1000 lbs (or more...) less, it might be adequate.

 

The primary reasons as to why I am considering a 6.2L are as follows:

• Affordability
  • 6.2L/6.5L diesels can be purchased for less than $800.
    • In comparison, a stock Cummins 3.9L 4BT may currently be purchased for $4,000+ on Truck Paper. The newer, more powerful variant of the 4BT, the 4BTA, is even more expensive.
    • A quick eBay search shows 4BT engines running in the multi-thousand dollar range.
  • 6.2L/6.5L diesels from HMMWVs can occasionally be purchased at government auctions for a relatively low price.
  • Considering the original Chrysler 3.9L LA V6 has 68,488 original miles, I could recoup some of the cost by selling the engine.
  • Price to Performance Ratio - N/A 6.2L:3.9L 4BT (Stock)
    • $800 6.2L: 130HP/240lb-ft = $6.15/1HP, $3.33/1lb-ft
    • $4,000 3.9L 4BT: 105HP/265lb-ft = $38.10/1HP, $15.09/1lb-ft
    • With modifications such as a turbo, the 6.2L will achieve reasonable power while already being significantly cheaper than the 4BT.
• Simplicity
  • Minimal electrical work required as the 6.2L does not require an engine computer and is fully mechanical.
  • Chevrolet small block/big block engine mounts are directly compatible with the 6.2L.
    • The existing Chrysler mounts should be able to be modified to accept the 6.2L, but I am not 100% sure. This is where some fabrication may be needed.
  • Chrysler transmissions may be paired with the 6.2L through an adapter, therefore potentially eliminating the need to adapt a GM transmission.
  • Variety of compatible GM of transmissions to choose from if needed.
  • Existing fuel system may be adapted and reused.
• Size
  • A 6.2L has a length of about 29.5". To make sure a larger diesel radiator and radiator fan fit in the smaller engine compartment of the 1987 - 1990 Dakota, every fraction of an inch counts.
  • Measuring from the firewall to the fan shroud, the length is about 29"; an alternative engine such as a 4BT (30.6" in length) would be a very tight fit if not dimensionally impossible.
    • In stock form, the 6.2L V8 makes slightly more power than the 3.9L 4BT I4 while fitting in the Dakota's engine compartment.
• Dakota Factors
  • 2WD Rack & Pinion Steering
    • 4WD models used heavier parallelogram steering.
    • Best in class handling, superior handling to larger, Dodge, GM, Ford trucks.
  • According to Allpar, the 1st Generation Dodge Dakota has the 'highest percentage of corrosion protection material ever used on a Dodge vehicle'.
    • This is important as I plan on keeping my Dakota long into the future.
  • At the time of purchase, my Dakota did not run, but that allowed me to get it at a very reasonable price and it has very low mileage with 68,488 miles on the odometer.
    • The truck is in excellent shape and runs well with its original engine. The original paint is intact with the exception of minor fading on the hood and roof.
  • As you said, this project would also be an attempt to try something unconventional.

There's a variety of diesel engines out there, so if I come across something else that may be suitable and as cost-effective, I might go with that instead. I haven't made a commitment to one specific engine just yet.

The largest foreseeable drawback of the 6.2L is its weight.

It's definitely not a powerhouse, that's for sure, but I'm more interested in its fuel efficiency rather than its power. As 93 ragtop said, it's not the best in terms of efficiency, but it should provide a decent bump in torque output and a relative increase in efficiency over my truck's original 3.9L LA V6.

 

Looking at the 6.2 diesel, it's small block chevy size. If the picture I am looking at is correct, the oil filter is where the chrysler starter is. Transmission would never work. Would need to go gm transmission.

Length is a concern on the 87-90, its tight. My 6.1 hemi fits and it's a huge engine.

It's an interesting swap, you better be able to fabricate and solve packaging problems.

 

when I had my 93 club cab it came to me with a 318 and dead trans. I converted it to an NV3500 and it became an easy 20+ MPG machine. if I drove it "hard" Id still get better MPG than my current 99 club cab with its wheezy 3.9....... and it went like a bat out of He11 when needed, as well. I didn't do the swap for MPG, but because it was what I had available/ and stick shift is much more "fun" to drive. I miss that truck...
I got 72k good dependable miles from that truck, drove it all over the place, pulled my camper with it too.... I miss that truck. it was in a very bad wreck, bent the frame enough to puncture the oil filter and the bed wound up offset 8" to the driver side at the front of the bed/back of the cab...... so it was definitely not fixable.

 

Quote:

Originally Posted by Glen440

Looking at the 6.2 diesel, it's small block chevy size. If the picture I am looking at is correct, the oil filter is where the chrysler starter is. Transmission would never work. Would need to go gm transmission.

Length is a concern on the 87-90, its tight. My 6.1 hemi fits and it's a huge engine.

It's an interesting swap, you better be able to fabricate and solve packaging problems.

Glen, I wonder if the picture you were looking at was the even older 5.7 diesel, which was based on a 350 Oldsmobile block......
The 6.2 is made by Detroit Diesel..... and it is wide
Attached is a ebay listing showing pictures of the 6.2. https://www.ebay.com/itm/1991-GM-LMM...4AAOSwZH1fJHE9

As far as transmissions go, it came with a turbo 400 or the 700r4.... I agree, he needs to use the GM transmission and then hopefully just make a new rear mount.
I believe you are 100% correct, that this is going to require fab skills and equipment to make it happen.
The third film showing the 6.2 in a dakota, has some things that are going to be different then the 2wd version. Starting with he put a solid axle , with leaf springs.
I suspect oil pan clearance will be an issue. Heck, even on the 5.2 the pan was redesigned for clearance compared to the ram pan.