89 GMC Cummins conversion

[COS399]

Originally Posted by brimc

That's great. Got any video of the first start?

Brian, Sorry but no video of the first start up.

[COS399]

Originally Posted by 6BT 56

Yep that is a great job you are doing. Im looking forward to hearing more abt the 4l80 and how the controller works . I have a 2002 burb that i was thinking abt a cummins swap . I would need the same trans controller I guess. Oil pan is a issue on these IFS trucks I hear as well. I have had my eyes open for a truck like yours for some time now to do just as you are doing . Keep up the good work .

Thanks. I have been wanting to do one of these for a few years. I bought the 2000 Dodge donor truck over 2 years ago. When I finally decided to look for the crew cab to put the motor in, I found a guy with a '78 GMC K35 that was willing to trade me for a Honda 300EX. We met in Great Falls to do the trade and afterwards I stopped at a store and some gentleman asked me about the truck on my trailer and informed me that he knew a guy selling a similar style truck. I took down the information and a few days later I was once again hooked up to the trailer to look at the truck for sale. Of course I told my kid that he could have the '78 and I decided to make the '89 my project truck.

Ken, at Autoworld conversions, has done a conversion similar to yours and it looked to me like it came from the factory with the 6BT.

[COS399]

Well, a call to Ken and Jeremy and I had the answers I needed to solve my firm steering issue. The steering pump had air in the lines and by jacking up the front differential and turning the wheel left and right without the engine running removed the air pockets. Afterwards, I fabricated a stainless steel bracket to mount the coolant reservoir to the fan shroud. I then took it out for its first shake down run. I will describe it as "Awesome." I know it wasn't pulling a trailer or anything but it ran great and as for the 4L80E, it shifted so smooth that I was worried it wasn't shifting but the engine wasn't revved up. It seemed like an ATV with a CVT transmission.

Here are some pictures of the coolant reservoir, hole for the transfer case shifter and the Lokar transmission dipstick that I needed due to its flexibility.

[ryanroo]

this is a sweet truck. well executed work!

Ryan

[6BT 56]

Glad to hear it is under its own power now . A sweet truck for sure . The 24 V engine uses a ecm to run the eng correct ? What was the harness like to adapt to the chevy ?

I remember when I put the 92 eng in my 56 . The hook up and pluming was almost too easy . The 2 Ryan's help a lot . Other wise it would have just been easy . They get credit for the "too." Lol.

[Dieselwrencher]

Those Lokar dipsticks have sure went up. I'm going to wait to see how a manipulated stock one fits my truck before biting the bullet and buying one. I hate filling the trans in my Vette that has one. Such a small dang fill hole.

6bt56, yes sir. The 24v ISB's use an ECM to run the engine. Mainly to control the injection pump etc. You basically use 7 or 8 wires from the dodge harness plus some for the OBDII connector and you can get them to run. It is a lot of wires to get rid of for sure. You pick out which wires go to the OEM cluster and use the stock GM fittings and adapt thread sizes if needed to get the stock gauges to work. Definitely not as simple as a 12v.

[COS399]

Originally Posted by ryanroo

this is a sweet truck. well executed work!

Ryan

Ryan, Thanks. I have looked at your build as well and I am impressed with your handy work.

Originally Posted by 6BT 56

Glad to hear it is under its own power now . A sweet truck for sure . The 24 V engine uses a ecm to run the eng correct ? What was the harness like to adapt to the chevy ?

I remember when I put the 92 eng in my 56 . The hook up and pluming was almost too easy . The 2 Ryan's help a lot . Other wise it would have just been easy . They get credit for the "too." Lol.

Yes, the 24 valve has it's own ECM. It is mounted to the left side of the block behind the fuel filter. As for the wiring it was pretty easy since you technically only have to hook up a fuse, relay and a switch to make this thing run. As for the transmission computer I had to tap into the TPS, connect two plugs into the transmission, tap into the brake pedal, hook into a 12 volt power and then a ground. Wiring the Intake heater relay was pretty easy and then I added the 6.2 water temperature and oil pressure switch to make the factory gauges work. Hooking up the "Glow Plug" indicator light was fairly simple as well. Of course some of these things you don't need and with the PCS transmission controller you can do some additional really cool things such as using factory switches/buttons to manually shift the transmission.

[COS399]

Originally Posted by v-man

Nice truck! Gotta love those 89 Jimmy's. The dieselwrencher is right. My tranny was heating up with similar cooler placement and it was apparent my skid plate was restricting air flow so I added a fan on a toggle switch which helped. But when towing heavy my tranny temps where still on the hot side so I squeezed another cooler between the grill and the innercooler and hooked them together in a series loop. Now my tranny temps are awesome and I rarely use the fan. Keep up the nice work.

V-man, Thanks for the compliment and sharing the information on the trans cooler. I have mine on a thermostat and I will definitely keep an eye on the temperature gauge. I'm not sure if my 5th wheel toy hauler will fit on it anymore now that it is lifted. If it doesn't fit then I may just have to use my '88 CC DRW R30 12valve Getrag tow vehicle.

[COS399]

So here what has happened in the last week: installed new exterior mirrors, painted and installed the grill and headlight doors, mounted front bumper, installed and hooked up new fuel lines down the left frame rail, installed hood, and got lucky and found a red GMC tailgate that was in really good shape. I also attached a picture of the bump stop extension. Sorry about the dirty vehicle but I haven't cleaned it up yet.

[Hankster]

Good lookin truck. Thats funny about that grill.. I bought one just like it and its painted black too.

[Dieselwrencher]

It looks really nice. Nice score on the tail gate!

[COS399]

Originally Posted by Hankster

Good lookin truck. Thats funny about that grill.. I bought one just like it and its painted black too.

Originally Posted by Dieselwrencher

It looks really nice. Nice score on the tail gate!

Thanks guys. I am still trying to narrow down the tire/wheel size and style. It's narrowed down to 34 or 35s, 17 or 18s, and classic aluminum M/T or something with some black and machined.

[72MARIO]

The DC2 DICK CEPEKS would loook great on it

[COS399]

Over the last couple of days I extended the rear load level braking assembly. This had to be extended after installing the lift kit. I found a winter grille cover behind the rear seat. This will come in handy living in MT. I am still working on cleaning up and securing all the wires. Lastly, I didn't like the way the coolant overflow hose looked so I drilled a hole in the top of the tank and ran the line through the new opening. In hindsight I should have just left the factory overflow tank mount on the fan shroud.

[COS399]

Here is the latest: welded in the piece of metal that I had previously cut to move the transfer case lever over, scored me another GMC tailgate in really good shape, mounted and hooked up the transmission temperature gauge, and wire loomed the wiring under the hood. Getting closer to having it on the road. I still need my tire and wheels as well as having the exhaust finished.

[COS399]

a few more under hood pics.

[Dieselwrencher]

It looks very nice and neatly done. Great work!

[COS399]

Originally Posted by Dieselwrencher

It looks very nice and neatly done. Great work!

Thanks Ryan. Well we took it out in the snow last night and had a little fun with it. I am still impressed with how it handles and runs. The heater works good in sub zero temperatures.

I didn't mention it previously but I was worried about fan to radiator clearance and so I used the 1st generation fan clutch and fan hub. The fan itself is out of the 24valve and I raised the shroud just a bit and of course had to shift it over about 1". It seems to work but only time will tell.

[6BT 56]

Nicely done . It truely looks like it came that way. I can only imagine what would have happined if GM had made a deal with cummins in the good old days , instead of dodge

Looing forward to seeing it with new sneakers .

[COS399]

Originally Posted by 72MARIO

The DC2 DICK CEPEKS would loook great on it

72 Mario - thanks for the input. It has been a tough decision but I ordered up my tires and wheels today. Wheels will be 18" x 9" and the tires will be Toyo A/Ts 35" by 11.5"

[COS399]

Originally Posted by 6BT 56

Nicely done . It truely looks like it came that way. I can only imagine what would have happined if GM had made a deal with cummins in the good old days , instead of dodge

Looing forward to seeing it with new sneakers .

6BT 56 - Thanks for compliment. I was shooting for a clean and somewhat factory look. Being able to see what members are doing on this forum and being close to Ken (Autoworld conversions) helped greatly. I want to run it "as is" a while and then go back and remove any wiring under the hood that is not hooked up to anything. My plans are to clean up the wiring under the hood of my '88 Chevy CC 12 valve conversion this summer, after a break of course.

[6BT 56]

I think its the red rockercover , it just makes everything else blend into the red firewall.

Got any pics of the other converted truck ? Keep up the good work

[COS399]

This is the only one that I have available right now. I was going to take a picture of my 88 next to my 89 and then again after the new sneakers get put on it.

[Dieselwrencher]

That's a great looking truck too. Those wheels are really nice. It should look big pimpin.

[6BT 56]

Thats a good looken bed on that truck . All the cool square trucks rotted to death around here long ago. I go for a trip to the sunny south and Im amaised . Im having conversations in the 7/11 parking lot with guys with 20 year old trucks and complementing them . They look at me like im from the moon . Lol, Just a truck to them .
You said that truck has a 1st gen 5.9 and getrag? Thats the same combo I put in my 56 . Sure was straight froward .