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post #1 of 7 (permalink) Old 07-28-2007, 12:43 AM Thread Starter
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Cummins 855 series differences......

Okay, I've asked about the Cummins 855 series engines before, but I have some new info.

The engines:
This is what is on the tag. Both are 1977 manufacture (original for trucks I guess)
NTC 350 and block has "Big Cam" cast in it (In a K100 Kenworth)
NTC 290 and block has "Big Cam" cast in it (in a IH Transtar II 407B)

A third truck, also a 1977 has a 855 Cummins, but it is missing the engine tag. The intake says Formula 290 on it. (I've asked about how to ID this engine w/out the tag and some say look at the casting numbers). I couldn't find the casting of "Big Cam" on this engine (as I looked at the same spot where the other two had it.) Engine is kind of Cummins Tan, the old light brown. Not sure if it is original, as I don't know if the "Formula 290" was available for a 1977 IH Transtar II (CF4070B). It looks as if it was repainted, since I could see some old paint under the engine (similar to the other NTC 290 in the other IH).

Any how, what is the "differences" between a NTC 290 Big Cam vs a Formula 290???? (Would the Formula 290 have the 'Big Cam' cast in a different spot???? or it isn't a Big Cam)???

1999 E-350 Cub Wagon, 7.3L Power Stroke, E4OD, 3.55
1990 E-350 Club Wagon, 7.3L IDI, E4OD, 3.54LS x2
1994 Chevy C2500 6.5L TD, 3.42
1983 F-150 2x4, 4.9L, C-6 w/GV-OD, 3.55 Farm pickup
1981 C-8000, 3208 CAT, RT-6510, Rockwell SSHD Tandems (Swap)
1981 VW Rabbit Pickup 1.6L diesel (project)
1978 VW Rabbit 1.5L diesel (project)
1977 K100C, NTC-350, RT-1110, Tandem
1977 Transtar II, NTC-290, RT-9509 Single
1977 Transtar II, Formula 290, RT0-9513, Tandem (project)
1974 C-750, 391CID, Clark 5 speed, Eaton 2 speed
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post #2 of 7 (permalink) Old 07-28-2007, 11:01 AM
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Re: Cummins 855 series differences......

One look at the Cam followers on the Drivers side of the block will tell you if its a Big Cam or Not.The small cam NTC's followers are Half the size (Height wise)of the Big Cam blocks.I am not sure about all the diff's in the 290's.One Big thing I think the Formula had a Nodular crank and was Not Forged.Step it up a little too much and they will snap... [img]/ubbthreads/images/graemlins/eek.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] I had Owned Both small cam 350 and Big Cam 400's Back In the Early 80's.The 400 I had worked over pretty good with Help of Bruce Mallison the Owner of Diesel-Injection of Pittsbugh.He wanted to try New things and It was done at Just the cost of the componenets for Testing reasons before Selling the Parts to the General Public.Thier was a Group of us Owner-Operators Running there Combo's of Pumps,Turbos and Injectors to name a few Parts LOL...There wasnt Much on the road that could Hang with Our Tks.It was pretty Cool to Have something Under the Hood that very few others had.CAT-Power Ha,Ha, There wasnt one that could skin me, No Way!As far as Worked Up Engines went Cummins Power Pretty Much Ruled the Road back then!! I miss those days(ramble Over) [img]/ubbthreads/images/graemlins/smokin.gif[/img]

07,F-250 4X4 6.0 Torqshift, Lariat, Highline package, S/C LWB.
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post #3 of 7 (permalink) Old 07-29-2007, 03:13 AM
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Re: Cummins 855 series differences......

The formula engines were all small cams and that light tan color.
They were set up for fuel milage, with the lighter crankshaft and small cam there is no sense in trying make more hp with that setup.

1991 F350 custom DRW, 4x4, 11' service box, 7.3

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post #4 of 7 (permalink) Old 07-29-2007, 03:37 PM
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Re: Cummins 855 series differences......

Cummins over the years

NT250 Small Cam N/A
NTC270 Small Cam Little rusty on the turbos?
NTC 290 Small and Big Cams I and II and they started Oil Piston Coolers 300/290hp and up.
NTC300 Big Cams all still made
NTC315 Same as 300 Oil coolers on these newer ones
NTC335 Small Cam Oil coolers Different Pump and injectors,
NTC350 Small/Big cam (ALL) Now with an aftercooler and a little different pump and injector setup.
NTC380 Big/Small cam, Marine specs different water pump and aftercooler, same as later BC444 and 400s
NTC400 Big Cam I,II,III,IV all different Holset turbos valve timing Aftercoolers and as stated formulas have a different crank,

Hope this helps,


2002 Ford F250 6speed Extended cab long bed XLT sport, black 5in lift 35" tires three 12" Memphis Subs, over 2000w power, Kenwood CD player with video screen. Powerstroke out and 6BT Cummins 12v IN 20MPG!!!!

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77 Kenworth, KTA 15over Eatons on Tortion

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61 B75 mack on 84 pete frame 400 Cummins 14615 on air ride SQHPs Long and tall Black and chrome
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post #5 of 7 (permalink) Old 03-04-2010, 12:58 AM
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Can I add a jake brake to the 290 cummins
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post #6 of 7 (permalink) Old 06-30-2010, 08:10 AM
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Cummins NT855

Some one help me with the injector setting for NT855G4
The pulley markings are A,B,C & TS

Thanks In Advance
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post #7 of 7 (permalink) Old 07-01-2011, 09:21 PM
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290 big cam CUMMINS engine The serial # on that engine is at the back on the left of the block just below the head and will be 8 #s.
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