new to this form need help with engine swap

[bobbytoday]

hey guys I am new to this form and I have some questions that someone might be able to help me with please.

I have a nhc250 in my m813 and want to icrease the horse power.

is there a way to increase the hp by turning up the fuel pump or messing with the governer? I want max performance bc the truck lags on hills towing.

Also I have anoth m813 that I am restoring and I want that one to be alot stronger so I am looking into re-power the nhc250 and put in a ntc400, has anyone done this or know how to do this?

I wonder which nhc400 is the best highest perf one and what can I do to max the performance on the ntc400? can I keep the same transmission ? do I have to fabricate any parts? thanxs Guys!
orthofay@aol.com

 

[gimpyrobb]

Well this is the deuce forum, but alot of guys say the 250 should be left alone. Any bump in the power will melt it.

 

[M1075]

How many times/places are you going to ask about this?

 

[No.2Diesel]

opcorn:

 

[doghead]

bobbytoday, you need to add your location to your personal information(site requirement).

High performance, more power, more speed? With a Military vehicle? I don't understand

 

[Bozor1000]

 

[bobbytoday]

thanxs

Southern California

I am just trying to find someone who has done something I want to do so I dont waste my time and money. For that reason I will post everywhere I can think of.

Also I realize that the m813 was designed to be underpowered in order to prevent damage to suspension and drive train by a 20 yr old soldier. I think there is real potential for the truck to pull up hill at 65 mph and not the 40mph it does now and that with more power it has would increase off-road performance as well.

I am prepared to bite the bullet and fix whatever I break by have more power.

thanxs for your help !

 

[Jones]

Other than light modifications, I've found that stock is better. You can give it less restriction in the intake air or exhaust department but turning up the fuel often has a cascade effect. Now you need bigger injectors, turbo and IP work-- get far enough out there and you're doing gear train and suspension mods.
What about going with the higher output engine but leave it stock? Now you've upped your HP and torque without jeopardizing dependability. May not be as impressive as having a BelchFire 600 under the hood... but it sure beats having to rebuild it after every run.
However, IF you do go with the BelchFire 600; we want lots pictures of the conversion.

 

[madsam]

Bobby, Some people get a little like a women over sensitive about things being put in the wrong place. There doesn't seem to be a 5Ton hotrod forum. (Maybe there should be. ) So I put things like this in the 5 ton and up forum.

I understand why you want a little more power, My 816 is a dog at altitude. Some people are pureists. I am not. I need the truck to operate and do work at 10,000 feet. I do not wish to blow up my engine either, but it has about 1/2 the power it had at sea level. I just want to get back the power it had.

The issue from what I have read about the 250 is that it does not have oil cooled pistons. This means that they can melt if you turn the fuel up to high. I plan to leave my fuel alone, and that will make sure I do not over drive the engine. It will just perform more efficiently to the amount of fuel that is there. I have read that some have turned the fuel up to get 300hp, but the exhaust temps rise to 1800. I herd of one guy who melted his engine down, but I don't know how far he pushed the fuel.

The is one guy that is planning on putting a 400 in and it looks to bolt up, but I have not see it y self. Here is a link.
http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=19735&highlight=

Here is a link to the thread I started on rebuilding a turbo.
http://www.steelsoldiers.com/index.php?name=PNphpBB2&file=viewtopic&t=21740&highlight=rebuild+turbo

Good luck.

 

[madsam]

Oh.. by the way, Welcome.

 

[tmbrwolf]

Cummins had a turbo version of this motor, check with a Cummins dealer for parts availability, Wyoming forestry did some of their trucks this way for more power at altitude. It will not however make the truck faster, Cummins engines max out at 2100 RPM, more than that BAD things happen. The speed is a matter of gearing, these are very low geared trucks, I won't try to guess if there are different gearsets available.

 

[madsam]

It will not make top speed faster, aggreed. I think mine goes up to 2200 rpm. It is not top speed that I have a problem with. It is keeping top speed or any speed at altitude. But it might be able to keep top speed longer, or at least get above 20mph going up a steep grade.

 

[vtach]

How about a more efficient compressor (rebuilt D, polished IN/OUT, high blades) and a Cummins intercooler? Should be good for 30-50hp and would probably maintain stock temps.

 

[truckdoctor]

Reading your first question, an ntc 400 will go right in the same hole the nhc 250 came out of. The block is the same on most of the cummins engines from 250 hp up to 500 or 600. If it is 855 ci then it will fit in the hole. With the turbo you will be adjusting the exhaust piping but as far as everything else it should bolt up. I have heard there is some hood modifications to fit the intercooler and turbo. The trans should hold up to what you want to do as long as your not getting to carried away. If you want some more speed, consider finding a 9spd, 13spd, or 15spd with overdrive. This will help it get down the road better. As far as big horsepower, cummins built an ntc475 which was the twin turboed version of the 400. With some adjustments to the fuel pump, they can build much more. I'm not totally sure, but I think you can add the oil squirters for the pistons to the nhc 250. I would have to look at a parts book to confirm it. Have fun with the trucks thats what they're there for.

 

[madsam]

truckdoctor -- Do you have a pic or description of where the oil plumbing would come from on the 250 to a turbo. I assume there is a place to take off from for the hight pressure oil line to a turbo. The low pressure too.

 

[truckdoctor]

I don't have any pictures of a turbo system on a cummins at this point. I do have access to some engines at work and I will find out where the pressure tap is. I know the drain line comes off the bottom of the turbo and goes into the side of the block at an access plate below the turbo. I will post some pictures and give a better description this weekend.

 

[truckdoctor]

I looked at our m819 at work and a couple of ntc cummins engines. The oil return is in the same spot which is a 3/4" pipe plug just below the information plate and the exhaust manifold outlet. That is the easy part. Getting oil to the turbo will have to be a little more creative. On the ntc cummins engines, the oil cooler and oil filter are on the same side as the turbo. Cummins pulls oil from the oil cooler to the turbo. On an nhc cummins, the oil filter is on the left side of the engine mounted to the oil pump. At least it is on the m819 that I looked at. There is a couple of 1/4" pipe plugs on the oilpum/filter housing. Maybe check one of those and see if that would work. The next spot would be just above the oil filter there is a 1/4" plug there. Check and see if there is oil pressure there. Lastly, there is a 1/2" to 3/4" plug on the oil supply line going to the engine. It is the one that runs from the oil pump to the side of the block about half way back on the engine. You could probably use that one except that the starter is right there and you would want to make sure that the line was plumbed around the starter. I will look some more and see if there are other pressure ports available.