Cummins NTC-350

Little frame shake on that 79 Pete huh?

Saw you wishing for a yellow engine, are you thinking about a swap if you can't get more fuel out of her?
 
I don't know how much you know about the 855s but mine is a small cam. A small cam has a smaller injector travel than a big cam does, therefore less fuel. But I have bigger injectors in the way with bigger orifices that flow about 75% more fuel than the injectors that are currently in the engine.

I'd really like to compete a little better, especially when I'm 40' behind my dad with a 3406 cat. I know I'll never be able to hang with the electric motors, V8 Mack's or the KTAs. But I think at this point I'm going to play with this 855 a little more and if I come across the deal I like for a 3406 I'll jump on it.


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I don't know much, just what I've picked up from friends who have them. I was pretty sure yours was a small cam, which 3406 does your dad run? How's a 3406 going to help you over the small cam? Why not go Big Cam III or IV? I'm asking cause I'm itching for a truck and I'm just trying to learn a little more before buying.
 
I've read this thread from start to finish, over a few days. It caught my eye because I looked at a truck last week hoping it had a 400 cummins in it and it turned out to be a 350. He is asking next to nothing for it. I had always heard that the 350 wasn't worth much(I'm obviously new to big trucks) but after this thread I might have to go look at that truck again.

It has been very informative reading what all you have done/tried on your truck. Thanks for posting such detailed information, it is very helpful. You have a nice looking truck and something to be proud of considering the time/work you've put in it. You have to be pretty happy with the outcome given the size of the engine you are working with. Keep up the good work, I look forward to following this thread and your progress at future pulls.
 
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Meyers Farms said:
I've read this thread from start to finish, over a few days. It caught my eye because I looked at a truck last week hoping it had a 400 cummins in it and it turned out to be a 350. He is asking next to nothing for it. I had always heard that the 350 wasn't worth much(I'm obviously new to big trucks) but after this thread I might have to go look at that truck again.

It has been very informative reading what all you have done/tried on your truck. Thanks for posting such detailed information, it is very helpful. You have a nice looking truck and something to be proud of considering the time/work you've put in it. You have to be pretty happy with the outcome given the size of the engine you are working with. Keep up the good work, I look forward to following this thread and your progress at future pulls.
Click to expand...


Thanks a lot. I really appreciate it! I don't think this truck ever gets the recognition it deserves with everyone gawking over the Peterbilt.

I had a big write up to answer questions above but it didn't post from my phone. I'll have to re-type it. SmokinCAT has helped me out along the way. He has a big cam and is also very very knowledgeable about these engines.

All and all I am very happy with this motor, especially since it is still running stock injectors. If it were making 400 hp to the ground I'd be super happy. I have "big" injectors on the way, but I have to do some tuning once I get them in.

Thanks again MeyersFarm, the compliment is greatly appreciated.


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Bersaglieri, to answer your question, the reason I'd like to change out engines is that the small cam just isn't capable of the horse power because of the little amount of fuel that can be put to the engine.

The 855 is a low pressure common rail fuel system. The injection event is created by a lobe on the cam shaft which pushes a push rod that operates a rocker arm that causes the injector to fire. In these motors the barrel and plunger are inside of the injector and all the injection pressure is created by the injector. The small cams were have a smaller diameter cam shaft and are prone to premature failure due to wear and actually breaking the cam. If you look back through this thread, I put a new cam shaft in my engine. The hard surface had been worn off cylinders 3 and 4. Cylinder 4 wasn't even firing and cylinder 3 must have been very weak.

The small cam also has a smaller cam profile than the big cams do. Therefore, less fuel can be run through a small cam fuel system than a big cam. The small cam, i believe, has 0.177" of injector travel where the big cam has 0.240" of injector travel.

Where a 3406 A, B or C uses an inline injection pump (I don't think I have to explain that). My father runs a 3406B, which hangs with the KTA, V8 Mack and Electronic Cat in our club. There is just more power potential in a 3406 than in my small cam. If I can get between 500-600 hp to the ground with mine some day, I would be super happy.

The only real reason that I have to go to a Caterpillar vs a Big Cam is just biased opinion. I think a Big Cam can make relatively the same power as a 3406 B or C, with some minor engine work (injectors, fuel pump and turbo), but its Cat vs Cummins.

With that I cannot fault this engine what so ever. I think it either really likes me and is thanking me, but it has done great for what it is. If it was 400 hp to the ground right now I'd be happy. But it runs like a sewing machine since i've had the pump rebuilt, injectors rebuilt and the new cam shaft. So I would not steer anyone away from an 855, depending on their goals.

I actually was against getting anything that didn't have a Caterpillar in it when I bought this truck, but it came along at the right time at just the right price. I have always wanted an A model Kenworth and this one just fell into place. There was some consideration put into selling it to buy something with a Cat or an electric motor, but I had just put too much time and effort into this truck to sell it. Plus I love it to much to sell it. Maybe some day it'll get a Caterpillar put in it, but nothing in the near distant future. I want to make 600 hp with this motor before I think about changing it out.
 
Excellent info, that basically put together some pieces of information I had floating around in my head about the power capability of those 3 engines. The inline pump vs cam fired injector makes sense now.

A NTC290 would be a small cam, correct? A truck down the road has one, but I'm not sure it it'd be worth my time. 4.11's and a RT1110 transmission.
 
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The injectors in those cummins are Unit Pumps. That's the term for creation injection pressure in the injector.

Just another little nugget for you.


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Bersaglieri said:
Excellent info, that basically put together some pieces of information I had floating around in my head about the power capability of those 3 engines. The inline pump vs cam fired injector makes sense now.

A NTC290 would be a small cam, correct? A truck down the road has one, but I'm not sure it it'd be worth my time. 4.11's and a RT1110 transmission.
Click to expand...

Depends on the year of the vehicle really, unless it has been tracnsplanted. There were some 290 big cams.
 
This thing keeps getting better with time! But I really think my driving abilities are getting better and better.

We got to the pull last night and the sun was out and shining. About half an hour before we go quite a bit of rain. So about an hour later they scrapped the track off and pulled our little tractors and tried pulling 2.6 with a little drizzle. The first 2.6 truck just lit the tires and went about 75 feet. So they brought the stock gas and diesel guys in, which in total there were probably 30-35 of them. At that point the rain had quit, so they started into our heavy pro farm class, 2.6 and our light limited super stock class. By the time they came around to us (last class of the night), the track was mint. It turned out to be a real power track. The track was pretty slippery for about the first 50-75 feet and then it took some power to get down.

My father was about 3 trucks ahead of me and after watching him I was a little nervous my little Cummins was going to handle the track. I thought the track was just going to pull the power away from it and wouldn't go very far. Well I left the line at about 2500 rpm, slipped the clutch out and tried to maintain 2500. Once I got the clutch out it lit the tires but then grabbed a hold at about 100 feet. At the other end, I felt the weight come on and she just kept digging and ended up spinning out. Usually, the weight comes on and it runs the truck out of power and just about dies. I was super happy with the way it pulled last night.

My "big" injectors came in the mail yesterday, so I'm hoping I can have them in and the truck running correctly for our pull Sunday. I cannot wait to see what it will do. I am more and more happy with this thing day by day!

Videos to come.
 
[ame="http://www.youtube.com/watch?v=bpOSeMFdHrE"]Kenwoth at the Allegany Co Fair 2014 - YouTube[/ame]

The big injectors have not gone in yet. I got them Monday and we had a pull Monday night. The rest of this week has just been too busy. I'm hoping Saturday morning I can get them in and get things figured out.


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I out my big injectors back in the truck Saturday. It runs correctly now but still doesnt shut off like it should. I have a few more things I'm going to screw around with to see if I can get it to shut off properly but not sure what the issue.

Anyways, with these new injectors I see about 450 psi of rail pressure going down the track and about 35 psi of manifold pressure. Before I only ever saw a little over 300 psi at the rail and 30 psi of boost. I could have drove the truck a little better today, and maybe tried a higher gear. But all in all it pulled well.

[ame]http://vid1166.photobucket.com/albums/q619/RockinRam96/MAH00020_zps2c48fbc6.mp4[/ame]
 
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[ame="http://s1166.photobucket.com/user/RockinRam96/media/MAH00020_zps2c48fbc6.mp4.html?sort=3&o=0"]MAH00020_zps2c48fbc6.mp4 Video by RockinRam96 | Photobucket[/ame]
 
Maybe it's my computer, but watching videos on photobucket is painful. Are the injectors giving you a noticeable gain?
 
Yeah Photobucket has trouble with the high definition videos, and I didn't want to upload them to YouTube because I was going to put our whole class into one video. I'm not to impressed with the camera we bought. When its zoomed it the video is pretty blurry but when it is fully zoomed out and focused it looks good. Maybe I need to mess with the settings some.

My truck has been pulling well with the new "big" injectors. It is consistent week in and week out. It has been spinning the tires at the end of the track instead of running out of power, which I am very happy about. I've been running 4th gear, which is the 2nd highest gear on the low side of my trans. I jsut dont seem to have the speed and momentum. If I could run a little faster mid track I think it could do a lot better. I think next putt I am going to try 5th gear, high gear on the low side, and see if I can get it started.

https://www.youtube.com/watch?v=46IQ6mFRVIc

https://www.youtube.com/watch?v=D0X8cpMy6y0

https://www.youtube.com/watch?v=4UQOe8Eld_w

https://www.youtube.com/watch?v=G3nyWYLJWGw
 
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Nice looking videos. If you could pull fifth, I agree with you that it would definitely help.
 
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