Cummins 855 535hp Rated

[74M35A2]

I've been meaning to do this for a while for the 250 folks, and finally had a chance to. The genset at my work is 855 powered, and the engine tag rates it at 535hp. Here are a couple shots of it. Just seems like normal old school Big Cam stuff. PT pump and aftercooler. She sings. No strings on this one...
No

 

[orgnal]

I've been meaning to do this for a while for the 250 folks, and finally had a chance to. The genset at my work is 855 powered, and the engine tag rates it at 535hp. Here are a couple shots of it. Just seems like normal old school Big Cam stuff. PT pump and aftercooler. She sings. No strings on this one...
No
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It should fit nicely in a HMMWV

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[Csm Davis]

74M35A2 looks like it says 500 hp to me.

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[someoldmoose]

No disrespect to anyone, anywhere, but why does it always seem like a surprise to find an 855 c.i. Cummins that makes power ? It's a diesel. It'll make whatever power it has the air and fuel to make. Want 1000 h.p. ? No problem. Just make sure the internals are built to take it or it'll be a very short lived engine. The nhc 250 was chosen because it makes gobs of torque at LOW r.p.m. to get a LOT of stuff anywhere it needs to get to. I know this isn't a lesson for anyone here but the 855 c.i. is a monster of an engine. At 250 h.p., with normal care, it'll still start right up when the next dominant species inhabits the planet. I LOVE THESE ENGINES. Done with . Hahahahaha

 

[red]

The big cam 855's can reliably make lots of power and last a long, long time. Small cam won't make as much power reliably but still pretty good.

 

[74M35A2]

Didn't say it was a surprise. Was posting external hardware pics for that power level if somebody is interested in seeing such.

 

[red]

What I could do with 535hp/1600ft/lbs torque+ in the m816.

Drove a m915a1 with a m923 in tow the other day, combined weight is a little more than the wrecker. That 400hp would move pretty well. Averaged a little over 6.5mpg on that trip

 

[simp5782]

74M35A2 looks like it says 500 hp to me.

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They dont teach numbers and reading in the Detroit area. They burned the schools years ago. Atleast you Mississippi boys went to school barefoot so you could learn to count higher haha

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[swbradley1]

After blowing up the pic I would agree it says 585 or maybe 595.

 

[Csm Davis]

After blowing up the pic I would agree it says 585 or maybe 595.

Because swbradley1 said it looked like a 5 on the end I looked up the engine and it is 535 so I guess discoball can read just can't take pictures worth a darn.

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[swbradley1]

Yeah and I meant to say 535.

 

[74M35A2]

You guys are a bunch of tool boxes. That 855 will drag me down the street in flames. The rest of yours, I'm not so sure about....

 

[WillWagner]

It's a morphadite. BC3 and 4 mixture. Used a bc4 oil system, step timing control, bc3 aftercooler, conventional cooling instead of low flow cooling like the bc4. These are rated at that power because they are only used part time and not for prime power, long term running, most likely coupled to a 20-30 kw generator end. Boats are rated this way too, recreational boats will have c series, like in your five tons, rated at 750 hp because they are only used part time, not a lot of hours, the Howells will only take it on a 3 hour tour once a month. Commercial, like a fishing boat, will have less power because it is rated as a continuous duty, meaning it will be on the gas steady for hours on end daily. Same parts, just less HP due to the duty cycle.

 

[jasonjc]

The 855 "block" was used in a lot of engines. It's all the stuff inside that makes the HP.

 

[gimpyrobb]

Hmmm...

 

[74M35A2]

"The Howell's"...my favorite! Are the piston squirts the only thing keeping a 250 from being a 500? These aftercoolers are everywhere laying in the dirt, and the turbo should be easy to ID. Up fuel, and you are off to the races. Hobby MV application is less duty cycle than any commericial app.

The gen head is pretty high rating, will check it later today. 1.21jW or something.

 

[gimpyrobb]

"The Howell's"...my favorite! Are the piston squirts the only thing keeping a 250 from being a 500? These aftercoolers are everywhere laying in the dirt, and the turbo should be easy to ID. Up fuel, and you are off to the races. Hobby MV application is less duty cycle than any commericial app.

The gen head is pretty high rating, will check it later today. 1.21jW or something.

 

[Scar59]

The 855 "block" was used in a lot of engines. It's all the stuff inside that makes the HP.

Wait a minute, I thought the HP rating was directly proportional to the size of the blue Cummins "C" badge on the engine... thanks for the photos, love steady state power units, love to listen to them purr.

 

[red]

"The Howell's"...my favorite! Are the piston squirts the only thing keeping a 250 from being a 500? These aftercoolers are everywhere laying in the dirt, and the turbo should be easy to ID. Up fuel, and you are off to the races. Hobby MV application is less duty cycle than any commericial app.

Not just the piston squirters.

The older small cam 855's (like the NHC250) suffered from early cam failures when cranked over 400hp. 200psi of fuel pressure after the pump is reliably all the cam will survive.

Compression ratio varies as well but not by much. Anywhere from 14:1 up to either 14.5:1 or 15:1 (can't remember which), higher compression on the lower powered models. The piston material was different as well. The 250 has a mostly aluminum alloy piston while the higher powered models have a more heat resistant alloy.

For a reliable build the small cam NHC250 is limited to about 300hp ish, maybe 330hp if you really watch the EGT's. This is assuming no internal mods and the truck that hauls.

A big cam 855 block on the other hand, 700-800hp can be built reliable in a truck that hauls often.

 

[simp5782]

Not just the piston squirters.

The older small cam 855's (like the NHC250) suffered from early cam failures when cranked over 400hp. 200psi of fuel pressure after the pump is reliably all the cam will survive.

Compression ratio varies as well but not by much. Anywhere from 14:1 up to either 14.5:1 or 15:1 (can't remember which), higher compression on the lower powered models. The piston material was different as well. The 250 has a mostly aluminum alloy piston while the higher powered models have a more heat resistant alloy.

For a reliable build the small cam NHC250 is limited to about 300hp ish, maybe 330hp if you really watch the EGT's. This is assuming no internal mods and the truck that hauls.

A big cam 855 block on the other hand, 700-800hp can be built reliable in a truck that hauls often.

They had a 915 truck at Malmstrom AFB that used to run around as the missle hauler. Come out of the base screaming down the road with escorts. Doing 100 or so with ease. I figured it was a heavily modified big cam.

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