4BT in a Dakota!

[Scollins]

I was cruising through the Alt. autos. dodge. trucks newsgroup, and a member there posted that his Dakota conversion in now complete. Not a whole lot of details, but he did indicate that he dropped in a 4BT. I replied to his post and told him about this forum, and that he should check it out. We'll see, sounds like a way cool conversion... .....

 

[Ray Torresdal]

Ask him to post details and pictures!!!

I have someone locally who wants to do the same conversion. If you can plead with this fellow to provide information, I'd much appreciate it! Ray

 

[redneckdr]

4BT

i just asked some questions on another thread about this very thing. sure would like to see a little 4 banger in my '89 dakota 4X4 convertible. hope we get some details and pix.

 

[Thierry]

Found info on 4bt in Dakota (long)

Found this while searching including photos

Hope every likes it.



As I reported a few weeks ago, the long time coming Dodge Cummins Dakota

project is on the road. I now have some pics loaded up on the web, sorry no

thumbnails or anything fancy. There are 4 as follows:



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The only thing missing is the hood and the A/C hoses.



Just a little background. We bought the truck new in 91 for a business

truck. Within a week after buying it I had the rear springs out and had

another leaf added. Seems to be a common problem, I had to do the same thing

to my Toyota in 82, they must spring these things for people that don’t ever

haul anything. The electronic ignition died the first year. Then about

three years ago the rear axle started making all kinds of strange noises.

The garage that my partner takes it to (I was not driving the truck at this

time) said that the axle was falling apart and that they could not fix it, go

to the dealer. Screw that, having done many Dana’s from 23’s to 70’s, I took

the thing apart and reset the carrier bearing adjusters as they had loosened

up.



About 2 years ago or less I was roaming around a heavy/medium truck yard and

saw a pile of 4BT Cummins engines with THM-400 trannys attached. A friend of

mine who is well seasoned in Diesel conversions looked at me and said "you

know", and I said "yea" (must have been Diesel telepathy). At that time the

Dakota was approaching 150k miles and the mileage was a pathetic 16 and I was

now driving it whilst the partner got a new vehicle. The guy at the yard

gave me the keys to a potato chip truck and told me to take it for a drive,

which we did. This particular truck had 70k miles on it. I gave him around

$2k and he pulled the pack out of the truck and junked the rest for the

aluminum, that’s where all the other 4Bt’s were coming from, potato chip

delivery trucks. I got the engine/transmission and all the parts I wanted related

to that such as shifter, drive shaft, air cleaner, etc.



We got the thing back to the shop and started working on mounts for A/C and

vacuum pump and moved the alternator and such. Also decided to add a Morse

cable transmission modulator as they came with a fixed one, it shifted at X rpm no

matter what. The engine used an 8 groove serpentine belt and so I added an 8

groove small GM alternator (105A) and a 10 groove Sanden A/C compressor and a

flat pulley (running off the back side of the belt) Ford vacuum pump. I

wanted the alternator and A/C up high and I wanted the A/C where the

alternator was for plumbing reasons so the alternator had to go on the other

side and due to hood height problems it had to be on the small side. The

alternator on my suburban became a sample and it fit OK, so just got another

of the same thing. I also machined the grooves off the fan idler (the thing

that one might think is a water pump but it’s not) so as to drive it

backwards. Had to do some major rework of the intake manifold cover plate

and the tube connecting the turbo’s compressor discharge to the intake cover

for hood clearance reasons. Also added a flame primer from a Perkins Diesel,

all of $20, rather than pay $600 plus for the Cummins electric heater unit.

The first test run of the new belt/pulley system broke the alternator case

and prior to that the belt kept running off the crank pulley to the inside.

Added another brace for the alternator and the pulley problem was caused by

Cummins not having a skirt on the back side of the crank pulley, so I made a

new one with a skirt. Second test run (on a skid) was perfect.



While this was going on the rear axle fell apart again. I had picked up a

Ford 9" from a Bronco to re-work for the Dakota primarily because I needed

the 2. 5 gear ratio to run the supplied THM-400 with no overdrive, and it also

was a much stronger axle that that 7-1/4" thing. Which in my opinion is the

correct way to design a truck, pick the axle ratio for your 1:1 high gear,

screw the overdrive, they are nothing buy marketing gimmicks. Anyway, I

decided to put the Ford axle under the truck with 3. 5 gears while still

running the V6 which turned out to be a smart move, that was one less

"project" to figure out later. Switching the gears back to 2. 5 later was a

breeze. Also the 11" brakes on the Bronco axle are MUCH better matched to the

Dakota’s front disks, my braking effort increased dramatically and yet I

still cannot lock up front or back easily on their own. I also put in a

"True-Trac" which I just love.



So then about 2 months ago it was just one of those days, the engine/transmission

had been sitting on a skid for 6 months or more and the position of the moon

and the phase of Jupiter, I had some people over at the shop and we just,

with little discussion, decided that this was that day and we pulled out the

V6 now with 202k miles on it and stuck the 4BT in there and began the long

installation process. I added a new cross member (removable) ahead of the

main one under the engine. The front engine mounts sit flat on that new

cross member. The Cummins engineering book makes a big deal about not

mounting a 4 cylinder Diesel to rigidly. So I did some tests on some

different mounts and it turns out that the mounts from the original V-6 were

soft enough and so I used them. The motor does vibrate a bit at idle but I

can imagine it would shake the truck worse if the mounts were stiffer. Then

came the oil pan. I ended up using the flange and the first 1-1/2 inches of

the pan, the rest was fabricated from scratch to fit the space exactly. I

decided to do this with the pan rather than touch the cross member which the

front suspension and the steering rack were all tied to. Ended up going wide

and deep to maintain the 3 gallon capacity, also ran tubes through the pan in

5 places and used long studs so the pan is actually held from underneath. I

figured with the idle vibration and the added weight of my additions I’d

rather have it held from below that to hang totally from the flange. Also due

to tight clearances between the front of the pan sump and the cross member I

added a strut from the back of the transmission going back to the center bearing

cross member to keep the entire assembly from moving forward during braking.



Other little items were mounting the Morse floor shifter in the old hole left

by the 5 speed and gutting the wiring leaving only what I needed. Radiator

is from a V8 of the same year. In the pictures the A/C hoses are not

installed yet, it seems that Parker is having delivery problems and I just

this week got the fittings I had been waiting 6+ weeks for.



As I reported earlier I am now consistently getting 26 mpg around town. So

far I’ve put 2k miles on but I have not yet tried a long highway run nor have

I tried towing anything yet.



Only remaining issue now that A/C hoses are on is getting the front to sit at

the right height. It dropped 1-1/2" and an alleged 2" lift kit from Rough

Country raised it 4-1/2", so need to remove the spacer and cut in half, that

should put me right were I want to be.



Lot’s of other little details, if anyone has any questions I’d love to chat

about it.





That is all,



je

-- email address removed --

 

[Jeepthing]

Good job and looks awsome Mybe I'll find a project vehicile to stuff a Cummins in Great Truck.

 

[BFaoro]

WOW

WOW I have a 96 Dakota , same color , but it is a 4x4, and a v8(318). I know I would be a single man if I tried this with my little Dodge. After I rebuilt my 40 International H I figured I would be sleeping under it

That is awesome I love it . Putting that in a 4x4 would be nice Please keep us posted on what you are doing and lots of pictures !!

 

[Crash_AF]

Found the old Dakota thread and sending it TTT... Oo.



Joe

 

[B. Gill]

sounds nice

just one question, how did you get around the smog requirements for a 91 truck, i mean when youget registered at DMV how will you get a smog certificate with a non factory diesel instead of a gassoline engine?

if there is a way please let us know'thanks

 

[GOTSOOT]

6bt in a dakota

:--) Jeff Garmon @ southern truck parts has a 6bt in his dakota. talk about hauling the mail. That`s right no misprint 6-ina row --the only way to go

 

[Crash_AF]

ttt Oo.