86 chevy crew cab 12 valve swap

[84chevyguyid]

I been working on my project for a year, been collecting pieces for several years. Thought I would share what I have so far. I started out with an 86 chevy 2 wheel drive crew cab long box. It was a diesel but the engine and trans were gone when I bought it, which saved me some work disassembling it.
I got a bus with a p pumped 12 valve in it that provided me with a motor and lots of other little trinkets to use on the truck. I pulled the front clip and the bed then had to remove the 2 wheel drive front suspension and mount up front springs. I used 1/2 ton chevy rear springs on the front. On the back I got some 4x4 chevy spring brackets and remounted the stock rear springs. I picked up a pair of axles from a 1990 dodge one ton with the 3.54 gears and got them mounted to the chevy frame, then it was time for the first test fit. More to follow...

[84chevyguyid]

I pulled the cab last fall and rolled it into the shop so I could tinker through the winter. The bus motor I am using is set up with an air compressor and power steering and I decided to keep the setup instead of going with the pickup setup. I am going to have air bags front and rear so the factory air compressor will work nice for that, also nice to have air to blow up 4 wheeler tires, ect. I built my own frame brackets using the second gen motor mounts. I had to make a custom mount for the driver side as the power steering pump wouldnt clear the stock mount. The frame brackets are welded in but the crossmember tying them together unbolts. I was going to use a 4l80e trans behind the motor but ended up going with an allison 6 speedout of an 06 duramax instead. I bought my adapter stuff from Destroked. The oil pan on the cummins was a front sump and I was able to reuse it by turning it around and getting a new pickup tube for a rear sump application. After I got the engine and trans mounts finished I tore the engine down to the short block and replaced all the gaskets and seals on it so hopefully it wont leak oil. I took the head in and had it redone and added 60lb valve springs to it. I put 4000 governor springs in the pump and bumped the timing to 15 degrees and did the killer dowel pin fix while I had the front cover off. Then it got a new paint job after reassembly.

[legendman]

6 speed Allison nice!! Subbed

[84chevyguyid]

I have lots of pics but it says they are too big. Havent had that problem on other forums posting pics. Dont know how to resize them. I read the faq section on pics but I am still confused...

[gerfunken]

Originally Posted by 84chevyguyid

I have lots of pics but it says they are too big. Havent had that problem on other forums posting pics. Dont know how to resize them. I read the faq section on pics but I am still confused...

I load all of my pictures up on google (picasaweb.google.com), but there are lots of other sites like Flicker and others that you can use. Then I use the "Insert Images" button and just copy the links of the pictures.

[84chevyguyid]

Havent worked on the truck for awhile but here are some photos that I never got to download earlier. The frame is mostly ready for the cab. I got the heater system pulled and the wiring pulled, need to finish removing the steering column and the hydro booster then I can take it over to get blasted and undercoated then the cab should be ready to set back on the frame. One thing thats slowed my progress is I got my left knee replaced the first of oct then did the right one a week ago. Kinda takes the wind outta your sails for awhile. Still like to get the cab on before it snows and freezes up but I am living on borrowed time now.

[Dieselwrencher]

Nice truck you're building here! I wish you a speedy recovery with your knee replacements! What tcase did you go with behind the allison? Is it an older GM RH drop 241 with an inputshaft swap? I have a 5 speed 1000 series I'd like to put in something, but the $1800 controller Destroked sells is my stopping point.

[84chevyguyid]

Thanks for the encouragement! I did use a 241 with a swapped input to fit the ally. Yeah the 1800 dollar price tag sucks, building something like this is not cheap for sure. I have an excel spread sheet with all the parts and services on it with price estimates. After I buy and or accomplish each item, I move it across into the "finished" column and adjust the price to what it actually was. I am into this thing 10 grand so far with an estimated 8 grand left to go. This is with me doing as much work as I can myself. Scary!!

[Dieselwrencher]

Originally Posted by 84chevyguyid

Thanks for the encouragement! I did use a 241 with a swapped input to fit the ally. Yeah the 1800 dollar price tag sucks, building something like this is not cheap for sure. I have an excel spread sheet with all the parts and services on it with price estimates. After I buy and or accomplish each item, I move it across into the "finished" column and adjust the price to what it actually was. I am into this thing 10 grand so far with an estimated 8 grand left to go. This is with me doing as much work as I can myself. Scary!!

I hear ya on the cost man! Everyone who starts thinking about a swap thinks their cheap. You start adding prices up and look out. I thought about using a GM 241 in my Longhorn but wasn't sure how it'd hold up.

[84chevyguyid]

I had that discussion with my buddy that manages a transmission shop. We both decided that for what I am using it for, that it should work fine. The swapped input shaft for example is out of the newer transfer cases that came stock behind the duramax/allison setup and when you are running in 2 high or even 4 high, the torque is basically running through the input/output shaft anyway. If I were abusing it pulling, mudding, or something like that then a guy would want the newer box but for daily driving and a little towing I think it will work just fine. I would like to post my excel sheet on here but not sure how to do that. Would be interesting for people to see.

[arrover]

Cool build and I would love to see your cost break-down.

[Dieselwrencher]

On your list I saw where you got EFI Live. Are you going to try to tune the trans through your controller with EFI Live?

[84chevyguyid]

Actually I haven't decided which way I am going with a controller yet. There are a few guys that are using a GM trans module from an 06 avalanche with an 8.1 motor and the ally 6 speed, then they are reprogramming it to work with the cummins then tweaking it with efi live. Another route is using a medium duty application allison controller but with that route, you don't get the tow/haul or the tap a shift functions and I don't believe you can use efi live with the allison system. I still have some time before I have to make that decision, hoping stuff for the 6 speeds gets a little more refined when I get to that point. Its amazing how fast things add up though huh? When I started my project I figured ten grand would come close to puttin it together, boy was I wrong. When I first started, I just wanted to throw the motor in the truck with a 4l80e trans I had kicking around and drive it but its hard to tear something that far apart and not do a nice job putting it back together. I dont want a show truck for sure but I want it to look nice and be reliable. Its a case of "while I'm at it"....

[Dieselwrencher]

Originally Posted by 84chevyguyid

Actually I haven't decided which way I am going with a controller yet. There are a few guys that are using a GM trans module from an 06 avalanche with an 8.1 motor and the ally 6 speed, then they are reprogramming it to work with the cummins then tweaking it with efi live. Another route is using a medium duty application allison controller but with that route, you don't get the tow/haul or the tap a shift functions and I don't believe you can use efi live with the allison system. I still have some time before I have to make that decision, hoping stuff for the 6 speeds gets a little more refined when I get to that point. Its amazing how fast things add up though huh? When I started my project I figured ten grand would come close to puttin it together, boy was I wrong. When I first started, I just wanted to throw the motor in the truck with a 4l80e trans I had kicking around and drive it but its hard to tear something that far apart and not do a nice job putting it back together. I dont want a show truck for sure but I want it to look nice and be reliable. Its a case of "while I'm at it"....

I have an allison PCM and a partial harness I thought about using. Just unsure as of yet. Mine is only a 5 speed as well. I just don't like the idea of building a truck, using the a1000, and then hating it because I can't tune it without a trip to allison 20 times until it's right. Or, spend $1800 for Scott's controller. Too much money.

[Vintage Windmills]

Awesome build! I love the way that 86 is two toned. You don't see many like that and those colors look nice while retaining that retro look at the same time. Are you keeping that scheme?

The costs are adding up but it sure looks like you are doing it right and it will be a heck of a truck when its done!

[V3500KING]

Nice build!

[ryanroo]

keeping a tally! HECK no. besides, half my cost is in horse trading and i dont know how you put that in the list... eh Ryan? i would probably blow an o-ring if i had actually added up the amount i spent on mine. and then if i tried to factor in how much it would cost if i had to actually pay for some of the fabrication...

Love the truck, ive been building a crew cab square in my mind for years.

[ponjohn]

Subscribing

[84chevyguyid]

I have an allison PCM and a partial harness I thought about using. Just unsure as of yet. Mine is only a 5 speed as well. I just don't like the idea of building a truck, using the a1000, and then hating it because I can't tune it without a trip to allison 20 times until it's right. Or, spend $1800 for Scott's controller. Too much money.

Here is a thread on allison 5 and 6 speeds.

http://www.4btswaps.com/forum/showth...p-guide-thread

I have chatted with howard some over the past year about his system. Sounds like it works great! The down side to it is if a guy wants the tow/haul and tap a shift functions. They arent available with the allison system. The gm system seems to be very complex from what Howard tells me, derating fuel for shifts, locking and unlocking the converter in a variety of situations to help with emissions, shift harshness ect whereas the medium duty allison system is more basic in its function. Will the allison medium duty system work for me? yes it will. Would the tap a shift function be awesome to have? Yes it would. Now you can see my dilemma, which to choose?

[84chevyguyid]

Been learning about what all I need for the allison trans controller and wiring harness. I decided to go the GM route so I can have the tap shift feature and hopefully the tow/haul feature. Been collecting parts to put the harness together. I spent the evening the other night drawing all the components out and making a schematic of the wiring. Got the trans connector, the tcm connector, and the tps. Ordered the terminals for the tcm connector, an obd2 connector with terminals and a nice crimper, should be in a week. I found an 06 shifter handle with the tap shift and tow/haul switches, should be here monday. I am going to adapt it to my stock column, hopefully it wont look to weird when I get done. I still have to round up the wiring and then I should be able to start building the harness. I ordered a tapered reamer for the dodge steering arm so I can bore it out to fit my chevy drag link then I will have the box hooked to the axle. I still need to get the cab blasted and undercoated then I can set it back on the frame for the last time!
I dont know what the handle sticking out on the tcm connector is for, anybody know how this is supposed to work?

[hick]

Its late... I've been on this blasted forum for 12 hours so forgive me if I missed this... But you may want to check out "howards allison conversions"

Its been awhile since I looked into it (I have moved about from a cummins and gone to the dmax/alli combo) but the Allison should run it self with a OEM Allison controller. All it needs is a power, ground, tach annnnnnnnnd one or two other things I can not recall at the moment. Once you start driving it, the allison learns and programs it self.

Call Howard. Very good guy and he will explain it far better then me... Like I said, I have been pipe dreaming all day

[Dieselwrencher]

I'm pretty sure that handle is to lock the connector in place. I'll try to remember to look at mine and see if it has it.

[84chevyguyid]

Wanna see a sad pic? Here is how my poor vette has looked for a year. Spent all my free time last summer tinkering with this damn cummins swap addiction. I did put a battery in it last fall and start it and warm it up for a few minutes. Got to do some cruising in it this year, my buddy bought a viper last fall and he says WE are going for a drive or two this summer. I have to buy some new front tires first.

[gerfunken]

Originally Posted by 84chevyguyid

Wanna see a sad pic? Here is how my poor vette has looked for a year. Spent all my free time last summer tinkering with this damn cummins swap addiction. I did put a battery in it last fall and start it and warm it up for a few minutes. Got to do some cruising in it this year, my buddy bought a viper last fall and he says WE are going for a drive or two this summer. I have to buy some new front tires first.

Such a lonely sting ray... my cars are that way as well. If I spend to much time on my truck, the Model-A will get a little bit upset and do something to get my attention. I've had to make it a habit of taking the wife for Sunday morning coffee in the '29 so they both remember that I love 'em.

[COS399]

Did you install the steering box/frame reinforcement plate behind your steering box? I put it on mine but didn't mention it or take pictures. I thought about doing it later but I'm glad I did it while the front clip was off. Keep up the good work.