Swap a Cummins into my hauler

upnover

upnover

Grumpy, decrepit Old Man
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Mar 20, 2005
Location
Morganton NC
I have a 84 Chevy car hauler. 454 BBC Chevy engine, 465 granny low 4 speed, 14 bolt rear with 4.10 gears.

I have been looking at several options. I have been thinking about getting another RV. Looked at several of those for sale. The down side to that is:
Another vehicle to insure, maintain, and store.

My other thought is to swap in a cummins 12 valve diesel. This would give me the grunt to haul more weight, ie a bigger camper. My biggest reason for wanting to do this is with the pop up, it's just kinda a hassle setting up, taking down. Not much storage, and seem to be constantly disorganized. I want a camper that I can have cabinets for all the stuff you might want when camping, a shower, toilet, beds, Heat AC and all that good stuff. I don't want a huge camper, but one with all this stuff.

Back to the swap. Looking to those who have done and have experience in doing this. I know nothing that I have will work, so I am looking at what engine mounts to use. What radiator, and what inter cooler, after market or an application from something else. I am looking at the engines that Brook(s) has for sale. low HP, but I am told getting more out of the engine won't be a big issue.Not looking to go to the grudge pulls, but want it to be able to pull the hills when I go to Harlan, Mnt City, and further west. I am also not looking to go 80 MPH, 70 tops, so with that, I know an over drive tranny would do best, but unless you have a pretty good tranny, the MGF don't recommend towing/hauling in OD. So if I end up with a 1:1 high gear tranny, what gearing would I need to go in my current axle. I am thinking 3.55-3.73 to get me into the rpm range that will keep the engine alive. BTW I am running 215 tires.I went down in size because the 235's were touching in the rear and causing blow outs.

So if you know something about this swap, please post up!
Thanks
Chip
 
Tennessee Diesel Conversions have the best mounts in my opinion as far as ease of use and placement go. I would use a 47rh trans and a 205 t-case behind the Cummins. The factory radiator will work fine and use a 2nd gen Cummins or a D-max cooler. Check out 4bt swaps.com, they have a 6bt section as well. Also chech out cumminsforum.com too.
 
If you want to run a 1.00 to1 trans and the tires you have you will need to swap your axles for a Dana 61 so you can have the 3.08 ratio. They came in the early Dodge Cummins trucks. With my truck, 4.10 gears, 35s, 0.69 overdrive in the 47rh I am about 2100 @ 70mph which is perfect. The 3.55s might work for you depending on your overall tire height but only with an OD trans. Just remember for mileage and torque you want it about 2000 rpm it final drive.
 
I am interested in this, as I am contemplating the same thing.

As said above. The TN diesel mounts use the 454 frame side & very clean. stock rad will work, and add intercooler.

the MD trans that brooks has with his cummins are 1:1 top gear. As said, this would work fine with a taller tire. you could possibly keep the width and get a taller sidewall, or run spacers between the duals.

Another cheaper option is to find a spicer trans (3053, i believe) from a duece. They are like 0.85 5th gear, but have a 0.75 upgrade for it. You can also find some MD trans that are 5-6spd with OD top gear. They are a little more pricey but if you hunt you can pick them up reasonable. The nice thing about MD trans are the good clutches are alot cheaper then dodge's and they are typically cheaper and stronger.

If you want auto, the easiest thing to find is dodge trans. Most would recommend having them upgraded, atleast VB & TC. You can find MD autos but they are typically newer models, and more $$ and still many are 1:1 top.

The thing to really research and think about are: clutch linkage, brakes (do you have vacuum or hydro), alt, other accessories. hooking some of these things up can cost and/or become a headache.
 
the MD trans that brooks has with his cummins are 1:1 top gear. As said, this would work fine with a taller tire. you could possibly keep the width and get a taller sidewall, or run spacers between the duals.

You will need at least a 44 inch tire to run 70 with your current ring and pinion ratio. You would be at 2192 @70 with a 44 inch tire. Obviously not good for a tow rig. Use a Dana 71 with a 3.08 and you'd be at 2195 with a 33 inch tire. If you are running shorter than a 33, you need OD!




If you want auto, the easiest thing to find is dodge trans. Most would recommend having them upgraded, atleast VB & TC.

The Dodge trans will definately be easiest. A Dodge A518 or a 47rh will be perfect. The 47rh has a lockup which is cool too. Although not good for hauling.



The thing to really research and think about are: clutch linkage, brakes (do you have vacuum or hydro), alt, other accessories. hooking some of these things up can cost and/or become a headache.[/QUOTE]

Vacuum or hydro brakes are fine, the 6bt usually have the vacuum pump that the P.S. pump runs off of. If you get one from Brooks, thay dont have vacuum pumps but are cheap on ebay. Your GM P.S. lines will screw right into the Dodge pump. There is a heavy duty one wire alt. available for the 6bt. The one I bought from Brooks had one on it. And if you go with manual trans, the GM factory Master cylinder will work with the Dodge slave cylinder, just run your line between the two. This really is a pretty easy swap compared to some.
 
You could also use the Eaton FSO-6406a which is the 6spd overdrive version of what I have in my Chevy. Very beefy and will pull a house down.It will bolt up to my Bellhouses but you would have to do some tranny tunnel work. 6th gear is .78. If I had to do mine over again I would buy a nv4500.

My dually right now without overdrive and 40.5" tires is turning 2100 rpms at 60mph. With 4:10's
My dually with 37" H1's and 3:73 would run about the same rpm at same speed

My motors with a fuel plate and some injectors gets you back over the 200hp range for not alot of money.

My motor mounts were $150 on Ebay. They bolt to the cummins and use the gm frame side rubber mount.
 
Or a 5600! :driver:
 
Allison ax-4 fully hydraulic 4 speed auto 1:1 top end but stout as hell
 
He said he wants to be able to run 70. He cant do that with a 1:1 top gear.
 
I'm gonna watch this thread. I have a '95 3/4 ton with a 454 that I've been dreaming of a 6bt swap in. It already has the NV4500, but I hear there's a difference between dodge and chevy transmissions. Obviously I'm in the early stages of dreaming and have a ton more homework to do.:lol:
 
The GM ones dont seem to have the fifth gear issue the Dodges have. You just need the Cummins to NV4500 adapter and you're good.
 
02dmax said:
He said he wants to be able to run 70. He cant do that with a 1:1 top gear.
Click to expand...

Right but knowing what he's driving and will be pulling he may not need to run 70 :beer:
 
All good info guys, keep it coming!
One poster said something about a T case, the hauler is 2wd, so that isn't an issue.
Also, because I am on the Don't know much about a diesel side of things. Please spell out the acronyms.
These OD transmissions that are mentioned that will work, please, if you know, enlighten me as to what truck I would need the donor out of. Most salvage parts places I have dealt with don't know one from another.
Mentioned somewhere was going with a taller tire and using a spacer between the wheels. Unless longer studs are available, won't work for me. I am at the end of the stud as it is when wheels bolt up, and if I did that i would have to cut out the side of my bed for clearance.
 
a quick google revealed that there is a 3.21 gear available.
What kind of RPM's will this engine sustain? I mentioned wanting to go 70 mph, but I would be happy with 65 sustained.
 
The A518 and/or 47rh was in the Dodge Cummins trucks from around 89 to 95. Some late 95s had the 47re. You just need to make sure you dont get a 47re because then you need a controller.
 
- automatic trans have .69:1 OD ratio
- 1994-1995 cummins 2wd will hav the 47RH, the easiest swap for your applicaiton (A518 is non-lock-up converter, less desirable IMHO)
- 47rh is hydraulic controlled 1-3 gears, electric OD and torque converter lock. you'd need to provide a keyed +12V source to the trans connector, and either pressure switches or toggles to ground the OD & TC circuits for engagement/disengagement.

getstucksome has pressure switch setup on his 47rh swap and appears to have it tuned in fairly well.

FWIW a 12 valve engine will drive sustained 2000+rpm, you'd probably want one from the 96-98.5 range to get the better power numbers (assuming you want to keep it as close to stock as possible). Awspence had a 96 2wd with auto & 3.55's with 245/75-16's, and it was a bear to try to tow a car hauler & jeep comanche in OD.
 
I have a spreadsheet for gear ratio calculations. You say you have 215 tires, but I'm not sure what aspect ratio or rim size, so I guessed. I used the common gear ratios available for the 14B FF.
 

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Here is the chart with everything the same except having an OD of 0.73. I can change any of the numbers you like and repost.
 

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Tires are 215/85/16 They measure 29.5, no load

Also, not looking for an automatic, unless it's an Allison, and that isn't in the budget
 
I have nothing to add about a cummins swap other than they are cool, but the way I figure it from reading other articles is that you could probably buy a nice RV(or two) and figuring in tag and insurance, for far less than the swap will cost to get it done right.
 
89wrangler said:
I have nothing to add about a cummins swap other than they are cool, but the way I figure it from reading other articles is that you could probably buy a nice RV(or two) and figuring in tag and insurance, for far less than the swap will cost to get it done right.
Click to expand...

That is absolutely incorrect and rediculous. A 12 valve Cummins swap can be done cheap (reasonably) if you do your own work and get decent deals on parts.
 
If you dont want an auto your swap will be easier and cheaper. Just get a NV4500 (2wd's are cheap on ebay) and the adapter to bolt it to the engine, clutch, and you're good.
 
NV4500 2wd from what year trucks? Based on what Brook has for sale, is there a bell housing that will mate up to it?
 
Steve, to be honest I would love to buy an RV, and I still may. But I am thinking from what I have seen, somewhere in the $5-$6K add to that the cost of another trailer, and then the hassle of where to park it. I do not want to get rid of my hauler.
 
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