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Discussion Starter · #1 ·
What would it take to put a Cummins diesel and a NP4500 transmission in my 76 powerwagon? Obviously I need the motor and trans, but what about wiring and engine mounts and the crossmembers? Any info is welcome. Thanks
 

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i will be following this thread also..... i have been thinking about this swap witht he exeption of an auto. in my 77 PW....
 

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Physically installing a Cummins is easy. The mounts are similar to any gas engine and they are in the right location.

You will need to relocate the radiator. Most gas engines mount the radiator on extensions that place the radiator some distance away from the radiator support wall, so that the rad is closer to the engine. The Cummins is much longer and will require you to mount the rad flush to the radiator support wall. You won't nessarily need a big rad for a Cummins, but you should consider something about the size needed for a big block.

Most Cummins came with an intercooler. If the engine is sourced from a later model Ram truck, you can use the intercooler, but the intercooler pipes may not work. A Muffler shop can solve this problem and bend you up some pipes

You'll also need to fab up an exaust system. Although this sounds easy, the Cummins works best with large diameter pipes. For improved performance, you need to have an exaust with the least amount of backpressure and this means going to a 4 inch exaust. You have the option to run duals, but it's not nessary since a Cummins is an inline 6

I'm not sure about the tranny mount and crossmember for the 4500. However the 4500 is about the same length as a 727. If you need to, I'm sure you can use any crossmember and relocate it to where you need it.

Wiring for the Cummins depends on which generation of Cummins you get.

The 12V engines are all mechanical, you only need one wire to run the engine, another for the starter and one for the heat grid, and thats it. If you want to run the dash mounted information center, you'll need the wiring harness.

If you want to run a 24V Cummins, you'll need the wiring harness to run the computer.

In either case, much of the gas engine wiring harness will be useless.

Another thing to consider are the axles. If you have a 1/2 ton truck, the axles will be marginal at best. The weight and torque of a Cummins requires full one ton axles.

Ed

 

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Discussion Starter · #4 ·
Thanks for the reply. What year did they switch to the 24 valve, because I think I want to avoid that. I was planning on finding dana 60's even if I went bigblock, so that's no worry. With the 12valve is it possible to run after market guages for the water temp and oil pressure and the rest of the guages, or do you need the whole wiring harness from the donor thruck to d that?
 

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Not to Change topics, but WHy is it that the 24 valve aftermarket mods get more HP like 100+HP and 200+TQ while the 12valves get to about 260HP and 600 or something TQ. DO the 24valves breathe better? Can the 12valves be ported for better flow?
 

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Grayguy said:
Thanks for the reply. What year did they switch to the 24 valve, because I think I want to avoid that. I was planning on finding dana 60's even if I went bigblock, so that's no worry. With the 12valve is it possible to run after market guages for the water temp and oil pressure and the rest of the guages, or do you need the whole wiring harness from the donor thruck to d that?
98 1/2 was when they went to 24 Valves. You will likely need the Cummins wiring harness to use the factory gauges. The gas engine wiring harness may not have the same plug ends, and the differences in engine dimensions may require to lengthen or shorten the wires to reach the locations of the sending units on the engine block.

Ed
 

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Sug said:
Not to Change topics, but WHy is it that the 24 valve aftermarket mods get more HP like 100+HP and 200+TQ while the 12valves get to about 260HP and 600 or something TQ. DO the 24valves breathe better? Can the 12valves be ported for better flow?
The 24 Valve breathes better, but the real power comes from the fuel delivery pump, injectors and turbo. The 24V has a computer controlled fuel delivery pump, so increasing power is just a matter of changing the program (Usually with a chip) since the engine breathes well and usually come with pretty decent factory turbos, your power gains can get quite large with just a chip

The 12V is fine without having to resort to old fashioned hod rodding techniques, of porting, polishing, milling, head work, etc. The 12V can be bombed just like a 24V, but because it is not a computer controlled engine, power gains are made with physical changes to the pump, injector replacement, and turbo mods or complete replacement or twinned up.

Ed
 

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Yes you can use aftermarket gauges.
 

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Huh, I see. So making a 12V have about the same output as the HO 04 24valves 325HP and 600TQ, I assume the injectors and pump would have to be tweaked correct? Or to get to 325HP the engine would make 800lbs of TQ? Also the 1000lb engine weight, is it really that much more then say a small or big block engine?
 

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Sug said:
Huh, I see. So making a 12V have about the same output as the HO 04 24valves 325HP and 600TQ, I assume the injectors and pump would have to be tweaked correct? Or to get to 325HP the engine would make 800lbs of TQ? Also the 1000lb engine weight, is it really that much more then say a small or big block engine?
Yes it's possible for a 12V to make much more horsepower and torque than a new "600" Cummins, so long as you are using a 12V Cummins with a P-pump. (It's not possible to make that much power with a first gen VE pump, you'd need to swap out the VE for a P-pump, not cheap but very possible) The more torque you make, the better it is.

Yes the Cummins weighs in at about 1000lbs. The typical small block weighs around 300lbs. Why so much more? The reason the Cummins weighs more and is designed to last over 350K miles is due to the use of an engine block made of denser steel, and parts that are oversized. Yet with all that mass it still delivers excellent fuel economy and pulling power.

Ed
 

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you know i shoulda thought of this idea myself 2yrs ago. i was making a 79 dually 4x4 i didn't even think about cummins. course, it came w/a 440, but i'd rather have a cummins.
 

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I want to buy another Ramcharger, First one totaled ( Not by me though) and a Cummins powerplant would be great, but since the Ramcharger is shorter in wheelbase and having such a heavy engine upfront, does the truck become front heavy. LIke some rediculous percentage 60% front and 40% rear weight, how did you avoid that or counterbalance that since its about 500+extra pounds as you say the SB is 300.
 

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Discussion Starter · #13 ·
Does any one no of a good source for cummins engines? I'm kind of thinking I just need to do a lot of hunting till I find one I can afford.
 

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The small block weighs quite a bit more than 300#. http://www.team.net/sol/tech/engine.html has it listed as 525-550#; which is probably a much closer figure. A fully dressed 2.2L is supposed to weigh in at 335#.
But that Cummins is a heavy beast; that I will agree on.
 

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Sug said:
I want to buy another Ramcharger, First one totaled ( Not by me though) and a Cummins powerplant would be great, but since the Ramcharger is shorter in wheelbase and having such a heavy engine upfront, does the truck become front heavy. LIke some rediculous percentage 60% front and 40% rear weight, how did you avoid that or counterbalance that since its about 500+extra pounds as you say the SB is 300.
Anything that has a Cummins will be front heavy. It's unavoidable. But it's also important to understand the Center of Gravity (COG) in relation to the wheelbase of the truck.

If you have a very long wheelbase vehicle and you concentrated a given amount of weight or mass somewhere between the axles, you can say that each axle will carry a percentage of the total weight. One exception that would cause a single axle to carry all of the weight is if that weight is not between the axles (To the extreme front or rear of the chassis length)

If you kept tha same weight and lengthen the chassis, the weight that each axle carrys will change. The further an axle gets from the COG, the less weight it will carry, and vise-versa. A shorter wheelbase chassis will allow both axles to equal out more because both axles are closer to the COG. You can say that as you go to a shorter wheelbase, the closer to 50-50% you will get.

In a 4wd RC, the wheelbase is short, yet you'll have much of it's mass located at the front because most of the heavy parts are located at the front. The engine, and front axle (In my case a heavier Dana 60) are at the front, but there is plenty of mass at the rear as well. You have the tranny and t-case in the middle, and you have a rear axle, fuel tank, and the majority of the body weight at the rear.

You can reduce some of the weight at the front, by replacing heavy steel sheet metal with light weight fiberglass body panels or reloce weight by putting the battery and other parts in the back.

Or you can add rear weight by installing a rear winch instead of having a front winch, mounting your spare behind the rear axle, etc.

Ed
 

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Sug said:
Is their a certain trick or way to figure out Front and rear Weight distribution instead of buying an expensive car weigh checker that puts a scale on each corner?
Go to any truck stop which has a certified scale, such as CAT scales, Interstate, Flying J scales etc.

These scales are designed to measure your total or gross weight and individual axle weight. When you pull onto the scales, you'll notice that there is three slabs of steel or concrete. Do not center the truck on the biggest slab, otherwise you'll just get gross weight. Split the difference and put one axle on one slab, and the other axle on another slab. This will give you both gross weight and individual axle weight.

Once you know what each axle is carrying, you can do some quick math to figure percentages.

Ed
 

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Thanks RXT for all the Information, but just like GrayGuy says, where would be a good place to look for a cummins engine? Their are autowrecker yards about 6 miles away from where I live, but they mostly have small cars and trucks, I doubt they would have a diesel. WOuld it be better to try to hunt for one from a Semi truck yard, or would that come with a fuller 600lb monster transmission?
 

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The problem with finding a Cummins is they are in high demand. Because of that, they command a higher price if you do find one. There are all sorts of people who want them. The morons who love Furds and Chebbys have sites showing how to install a Cummins into their trash. There are RV'er who want a better and more fuel efficent engine to replace their old BB V8s. There are trucking companies, delivery services, bussing companies who are replacing worn out engines, in their trucks, etc.

It's not impossible to find a wrecked Cummins in a junk yard, but don't count on them either. Most junk yards today are linked to a computer database and the internet, so that, by the time a wrecked Cummins arrives in a j/y on the back of the wrecker, the engine is typically already sold.

There are plenty of rebuild shops who sell reman. Cummins, but they command a premimum price and you need a core. You might locate a used Cummins in a school bus, or medium duty truck in a big rig type salvage yard, however keep in mind that although the Cummins has a longer service life of 350K, trucks can go that distance in a few short years. If you manage to find an engine before some reman. finds it, you'll have to rebuild it, and that isn't cheap. And BTW, you don't have to buy the big tranny.

The only way to buy a Cummins as cheaply as possible is to buy an entire Ram pick-up equipped with one. Keep your eyes out for fleet trucks that may have one. You will probably pay the going rate for the truck, and you will likely part out a perfectly good pick up, just for the engine. But that maybe your best option

Happy hunting

Ed
 
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