Cummins Power

[buildin72]

Hey guys. longhorn man told me to post my question here. Im building a 72 3/4 ton 4x4. my choice of power is converting it over to a 94-98 5.9L B-series 12 valve Cummins turbo diesel. if any of you guys have any info on tis conversion that would be of any help please let me know. thanks alot.

[llegos]

this isnt much help, but you can get some universal engine mounts from www.fordcummins.com And, if you trust what their site says and want to wait a little bit, chevycummins should be up sometime soon

[Rreemo]

Very interesting to see this....I've been keeping quiet about it myself, however, this is also what I have in the plans for my 71' SWB. Mine is a bit different though....I'm building it as a street-rod type project. Going for the diesel because I want something totally different with gobs of power and drivability to boot....and I'm a big diesel fan

I was originally thinking 24v to start out with, but after more research, I've decided on the 12v Cummins. The 12v weighs a bit less (approx. 1100#), and obviously uses much less electronics. That, with the fact that a wrecked-out/totaled 12v truck can be had much cheaper. I do plan to find an entire donor truck for my swap...I figure that's the easiest way to get everything I'm going to need.

Now then, so far we have been surveying the situation for the swap....physically, the Cummins should be easy to fit on the chasis, however, we have turned our focus to the issue of added weight and torque that the diesel is going to add. With that considered, we are thinking that we will likely box the mid section and rear of the c-channel frame to add to it's rigidity, as well as to add more weight towards the rear of the truck. I'm thinking that I may also fabricate some sort of an X-brace for the mid-section of the truck too.

Nevertheless, I have not found too much information on this sort of swap....there is one local guy here that has put an older 12v in a mid 70's Blazer, and he indicates that the swap was pretty straight-forward for him.

[buildin72]

yeah, like you said info on this conversion is definetly scarce. i origanillay thought about a 24v too... just because i found a wrecked 02 4x4 with a six speed for around $7000.00 but i decided against the electronics myself. a 12 valve is easier and cheaper to get power out of any way... not to mention a ton of more black smoke rolling out of the exhaust, causing many people to probably run off the road if it was emitting from an old 72 chevy!!! im sure you are likely to run into less problems regarding your project due to it being a 2wd. my choice of tranny/case combo will proably be my biggest problem. Cummins Power... aint nothin like it!!!!!

[TP from Cntl PA]

Rreemo, You'll have to do firewall work with the 5.9...............I don't have much clearance with the slightly shorter 6AT3.4 in my 71.........

Hope your going to run it in a 3/4 ton chassis..............IMO, I am right on the limit of the front ends capacity with my C-20 using the 900 lbs 6AT.

[Rreemo]

Originally Posted by TP from Cntl PA

Rreemo, You'll have to do firewall work with the 5.9...............I don't have much clearance with the slightly shorter 6AT3.4 in my 71.........

Hope your going to run it in a 3/4 ton chassis..............IMO, I am right on the limit of the front ends capacity with my C-20 using the 900 lbs 6AT.

I'd like to see some pics of yours if you have any - rreemo@sbcglobal.net. At this point I'm planning to run the 1/2 ton SWB frame, but of course with a lot of fab/reinforcement, and I'll probably run the 3/4 ton spindles on it....for springs I'll probably go with stuff from Air Ride Technologies.

We're still in the planning stages, so I'm looking for all the advice I can get on this.

Thanks!

[Tx Firefighter]

You should go over to www.turbodieselregister.com and look in their discussion forums. They have a "Cummins conversion" section where guys post about their Cummins swaps. It's free to read, but you have to pay 35 bucks to join for a year if you want to post or use the search. To me though, it's worth the 35 bucks to be able to ask questions, I've been a member off and on since 2002. I have 2 Dodge Cummins trucks currently.

If you change the little tab on the bottom of the screen to "show all posts from beginning", they have 55 pages of questions and answers about the conversions.

[1967k30]

1/2ton and 3/4ton frome are the same. I'm planning on going CTD 12V/nv4500/GM 32spline np205. I haven't been able to find a wrecked truck or a beat one for less than $4k and it was a 93'.As to doing firewall work it must depend on the truck,cause some guys say it fits fine.I was chatting with a guy in CO that has a 02' CTD HO/nv5600 6spd/np231c? in his 72'. The 24V's aren't near as mod friendly and I also love smoke .

[buildin72]

1967k30 im glad you posted... perhaps you can help me solve my tranny/case problem?! i to was planning on running the gmNV4500l/NP205 combo.
what all is involved in using this combo. i know i have to use the gm output shaft. i want to have a manual clutch release, so i need to get a bellhousing from advanced adapters to relocate the clutch fork from the passenger side to the driver side. when using a 205 originally coupled to a sm465, which is what im using, the tranny output shaft must be shortened and a special female coupler is used thats compatible with the male 31-spline output of the tranny and the male 10 spline input of the transfer case. other mods are also required, but i wont overwhelm u right off the bat. does all of this sound right to you, or do u know?

[1969 GMC]

Originally Posted by buildin72

1967k30 im glad you posted... perhaps you can help me solve my tranny/case problem?! i to was planning on running the gmNV4500l/NP205 combo.
what all is involved in using this combo. i know i have to use the gm output shaft. i want to have a manual clutch release, so i need to get a bellhousing from advanced adapters to relocate the clutch fork from the passenger side to the driver side. when using a 205 originally coupled to a sm465, which is what im using, the tranny output shaft must be shortened and a special female coupler is used thats compatible with the male 31-spline output of the tranny and the male 10 spline input of the transfer case. other mods are also required, but i wont overwhelm u right off the bat. does all of this sound right to you, or do u know?

Do you need passenger side drop on the transfer case?
It would be easier to get a 4x4 GM NV4500 that originally came with a NP241, and swap on a Pass. drop NP241 from a V-series 4x4. No custom adapter pieces, and you also get a lower low range than the 205 to boot. Just something to think about. Also an FYI, the NP241 has a higher torque rating than the NP205.

[TP from Cntl PA]

Frames are similiar(Section Modulous SP? is different I believe), but you will need the 3/4 ton spindles and hubs on the front...........Not to mention I am running 3/4 ton HD coil springs and they are almost stacked on top of each other. I am going to have to get that solved to before painting it.........

I am going to run my next on on a 2 and 1/2 ton 4x4 frame.......And just use the cab and front clip off a 67-72 GMC.............Mainly because of the strength and I can run a Roadranger Tranny

[buildin72]

this might be a stupid question, bu ill ask it any way... is there a difference in a air cab and non-air cab as far as room pertaining to to firewall?

[TP from Cntl PA]

Originally Posted by buildin72

this might be a stupid question, bu ill ask it any way... is there a difference in a air cab and non-air cab as far as room pertaining to to firewall?

Don't believe there is any where you'll need it. Got an email address? I send you pictures of mine..........Its not pretty but we been using it. Can't do the body work until winter is over with

[special-K]

On the GM diesel site,www.thedieselpage.com
,is at least oe guy that has swapped-in a Cummins i a Chevy 4wd(CUCV K/30).His name is Britannic and they have search.Also,about everyone there knows about it and who he is.So,just post the same question there.Tell`em C.K.Piquup sent ya.

[1967k30]

Mine has 1ton axels, lift springs on the front which are heavier than stock and HD rear springs so I can tow if I want.There's a guy on the Thedieselplace.com with a Duramax/nv4500/205 in an 85' k30 crew cab 4x4.It's pretty cool as well.

[buildin72]

ill try to check the Dmax out. that would be neat, but being how the Dmax's first production year was 01 i would say that it would be an expensive project. you say "highly modified 12 valve"... what all are you planning on doing to it? fuel plate, HX40, high flow delivery valves, 4000 gsk, injectors,???

[1967k30]

I don't know what all I'll to to it yet.I'm working at getting my 01' Duramax to 500hp/900-1000 fp.torque right now,which isn't too hard. I'd like 400+hp out of my 67' w/CTD.Yeah it'll probably get injectors,a different fuel plate,propane,maybe N20,I'll see how much $$$$ I have when I do finally locate a good CTD.It kind of started as a wheelin' truck but it's kinda turning more to a pulling truck but I'll see what happens.Seems you know a lot more about CTD's than I do.How would be the best way to get 400hp/800-1000 fp torque? PM me if ya want.

[4x4Poet]

IIRC, round-pattern (not fig 8) input mount NP205s mount directly to an NV4500 (maybe with a certain NV4500 extention housing). NV4500 alum ext housings have been known to break. Stronger, cast iron ext housings are available from the aftermarket. AFAIK, round-pattern NP205s came in GM 1 tons that had NP205s ('77-'8?). GearTechHD.com sells rebuilt, round-pattern NP205s.

ORD NP205 Tech

Whether you use an adapter or not, keep in mind the overall drivetrain length. The front driveshaft must have some decent length to it to prevent U-joint bind at droop. More if the 4x4 is lifted. Upgrading the front driveshaft to a 1350 CV and U-joints will make a little more droop angle available and will better handle CTD torque.

Custom motor mount brackets will likely be necessary. I'd use the Dodge motor mounts (new) and fab brackets to enable bolting them to the frame.

EDIT: Actually, I'd have the motor mount frame brackets fab'd. I don't trust my welding that much....

[1967k30]

To my knowlege the 241 only came in the last year of the "V" series 91'.I part 1tons as a second job so I deal with them all the time.Specifically the round pattern 205 came from 85'-90'/91'.Like I said some the 91's I have seen had a 241. The pass drop 241 was probably used most in suburbans after 87'.

[special-K]

I have a`90 Blazer I bought new.It`s a 4spd Manual w/NP241.

[1967k30]

Well,I found a CTD today.It's a 92' w/ around 110K.Looks like crap though.Been a ranch truck,probably all it's life,but runs good.What's it worth ya think? Got an auto/205 that I'd sell.

[special-K]

I`d like to find one like that.

[1967k30]

Just started taking the Dodge apart.Got the front clip off and have started on the wiring. I got the wiring harness all out except for where it goes up into the steering collumn.I don't want all that extra wiring for all the electric crap that the Dodge had.Did you that have done this use the Dodge wiring or make up your own from the Chevy stuff? I wish I had a camera I'd post up pic's as I go.

[buildin72]

what year truck did u get? was it the 92 u were talking about? if u get a first gen (89-93), that is what u want... a 92 or 93... these were the intercooled models.

[1967k30]

Yeah it's a 92' w/ an intercooler.I need to know how to handle the wiring and how to mount it.We have the whole body off the 67' it's going it and the Cummins is ready to lift out and set in the framerails.