Ready to get serious with crew cab

[M'staedt]

I've finally got all the major pieces for my crew cab conversion project. They are as follows:



- 1981 crew cab, short box, 2WD truck

- 1995 160hp engine, complete w/ A/C comp. , alternator, fan, etc.

- NV4500 w/ bellhousing, flywheel, clutch hydraulics

- Dana 80 w/ 3. 54 open rear from 2500 (SRW)

- complete wiring harness from 1993 CTD truck

- clutch linkage from 1993 CTD truck

- motor mounts from 1st gen CTD

- Rad, shroud, and CAC from 2nd gen.



My goal is to get all this together and running first, then BOMB the engine to somewhere around 300hp, 750 lb. ft. at the rear wheels.



My immediate concern and my question to those of you that have done this conversion is: Can this frame take that kind of abuse without the cab and box banging into each other or otherwise breaking something? Is there any good way to beef it up? I don't intend to do any serious towing (maybe 6 or 7000 lbs. MAX), but I don't want to have to baby this thing to keep from twisting it like a Twizzler.



Any insight I can get from the experience of those that have been down this path will certainly be appreciated.

 

[Hutchew]

I haven't had any problems with the frame..............

on my '85, and it's a 4x4. I did fishplate from behind the shock mounts to in front of the engine crossmember on mine, though. I compared a 93 frame to mine, and it looked a couple of inches taller. You might think about replacing your 81 crossmember with one from a later model ctd truck, as they changed the height of it for the Cummins, using a spacer to raise the gasser motors back to the original height. I didn't know that when I built mine, and had to use a 1" body lift to clear the bellhousing/firewall. Some others here have had no problems with this, however. YMMV.

What are you going to use for a fuel tank?

 

[M'staedt]

RE: the fuel tank...

It's my understanding that a fuel tank from a shortbox, fuel injected gasser will work. I guess there is a "well" in the bottom of that tank similar to those on diesels.



I haven't quite figured out yet what I need in the way of a pick-up / sender. I think gas trucks have a pump at the bottom of the pick-up. I assume this is not required for a diesel.



I have heard plenty of conflicting reports regarding the placement of the engine in diesel vs. old gassers. If the engine really does sit an inch lower using the diesel crossmember, it looks to me like it would be easier to modify (or create new) the steel engine mounting brackets than to change crossmembers.

 

[CrewCabDiesel]

Are you staying with a 4X2 ? or converting to 4X4 ? As for the frame, I was running a 4X4 crew cab with a 8' foot box, and never had any problems. I also was not stock, dyno was at 220 hp at the wheels and over 800 lbs feet of torque at the wheels pulling a 8000lb 5th wheel and a 16' boat in tandem. I would do as suggested ,and reinforce the engine cradle if you are going 4X4, with a 4X2 there is more support for the engine cradle because it also contains the complete front suspension. I used OEM Cummins engine mounts for a 89 to 93, and the Cummins drops right in after you leighten the drivers side engine mount hole. I would highly recommend that you have the cab off so the you can drop the Cummins in and also line up the transmission cross member and drill the holes correctly. While you have the front clip off, fix the A pillars I will bet money they are both cracked and leaking water into the cab. As for converting the truck to stick, remove the entire dash and windshield if you can, it will make the rest MUCH easier. Make a template from the donor truck to mount the clutch master cylinder, you are going to have to relocate the bulk head connector on the crew cab to the same place that it is on the 1st gen donor truck & you will need a MIG welder to do this, there is no way getting around this short of going with an automatic. Get a 90 degree drill adapter to drill the master cylinder bracket frame holes that go thru the steering column/brake & clutch petal frame under the dash. I do have some photos of my Cummins Crew Cab Conversions, let me know if you would like to see them and I will burn you a CD. I have done 2 Cummins & 4X4 crew cab conversions that turned out ok, just ask around, some of the guys here have seen my work.

Kyle

 

[Hutchew]

Yeah..........

'till you went and got ugly AND overvalved all at the same time, CC

Jes kiddin. Good to see you posting again, Kyle. Still gonna 4-dr that '01?



M'staedt, a fuel tank from an 93 FI Gas reg cab shortbox is what I used. Holds right at 32 gallons. The sending unit will work with your wiring harness with a little splicing, you'll need the connector for the gas rig. I don't know if a diesel tank pickup will work in the gasser tank, but that might be an option, too. I am assuming you are going to change out the dash & gauges to a later model? I removed the pump from the well and used a piece of silicone hose to lenghten the pickup tube to reach the bottom.

Everything else is exactly as CC said. Don't be intimidated by the clutch and wiring, it's cake as long as you pull the dash out, which also requires the windshield being pulled, which also allows you to fix the lower corners of the front cab pillars. Probably will need the cowl brackets to fix those cracks while your at it.

As long as you have all that torn down, you might consider swapping in the hydraboost brake system off a 97-98 CTD truck. That's what I did and I have awesome brakes now.

I had tons of pics on my conversion and lost most of them in a puter crash. That's a drag, I can tell you. Makes it hard to describe what I did sometimes. Good luck and keep us in the loop.

 

[Hutchew]

A few more things...........

The crossmember is a piece of cake to pull on a 4x4, 4 rivets on each side and out it comes. A 2x4, I think, would be a PITA, due to the suspension. Be carefull in modifying the original U-shaped motor mounts because the power steering pump is awefull close in that area, may not leave you enough room for it. I had to clearance my frame for the starter to fit without rubbing, but keep in mind, this is on a 4x4.

You are in for quite a bit of fabricating to make that 2nd gen rad. & CAC fit. It would definately be easier to use the 91. 5 to 93 CTD stuff, but that core support is a booger to find at a reasonable price. Let us know how that works out.

 

[M'staedt]

Thanks Guys!...

I've been watching this board for well over a year now and I'm very familiar with both of your trucks (all 3 of them? CrewCabDiesel, I remember you built a second one after a chance meeting with some little old lady?).



CrewCabDiesel... .

I am sticking with 2wd. I figure with the shorter box and the fact that I don't intend to do much, if any, heavy towing, my stock frame should be OK. I haven heard from anybody that's done a 2wd, I'm still a little concerned about my spindles, lower control arms, etc. I've never even seen under a 2wd diesel (non-existent where I live), so I'm not sure if there's enough difference to warrant trying to track down the bigger parts. I am converting the entire truck to air-ride, so springs will not be an issue.



Right now I have the cab off of the frame and completely disassembled. I welded up the cowl cracks when I removed the fenders. They weren't that bad - I was able to completely weld them closed so I didn't see the need to add the Mopar reinforcement kit.



Unfortunately, I don't have a donor truck to use as reference for the firewall modifications, but one of my coworkers has an '89 that I can measure from the engine side. I do have the entire hydraulic clutch system and bracket so I should be able to get it in the right place.



I would greatly appreciate a CD of pics! Let me PM you my address and you can let me know what I owe you for postage.





Hutchew...

Didn't you have (or still have) a web site documenting your project? I know I've seen pics of your conversion, including the hydra-boost brake conversion. It was probably your information that led me to the FI gasser fuel tank as an option.





All...

A brief update on where I'm at with this project...

The cab, doors, and fenders are primered and ready for wet sanding. I took all of that off of the frame and set them aside so I can get going on the driveline. As of last night, the bare frame is almost cleaned up and ready for paint, after which I will begin engineering the air-bag front suspension, then onto engine and trans install, then the 4-link, air-bagged Dana 80 and driveshafts.



Thanks guys... I know there are still some more crew-cab "converters" out there that haven't chimed in yet!



Mark

 

[83 crew cab]

Mark I thank thy have all ready hit about everyting the only thang I can thank of is the clutch stuff if you cant you the stuff from the 95 truck what I did becouse mopar does not make the pedal parts for they hyd clutch It gets located over abut 2 inches from the pedal to the left what i did has use a mechanical clutch pedal and opend up the speed-o cable hole and hook the clutch master cylinder right to were the push rod would have whent on the mechanical clutch George here is the web sight if you want to see any pics www.geocities.com/blown72rr/