Cummins NTC-350

I have gotten lazy an haven't called the local cummins dealer to get a shop service manual yet. Does anyone know the torque specs on the over head? Injector hold downs, injector rocker load, rocker box nuts, and jake box nuts?

I know most of you guys know what all this looks like, but for some of you that may not.

My injectors tested fine. They have new o-rings, filters and have been all cleaned up. The pump needed to be rebuilt and I had the put a little more rail pressure to it. We'll see how it all turns out. I cannot wait to drive this thing!

Well they guy I had coming to help me run the over head on this old Cummins, but he japed out on me and isn't available for over a week. If anyone could provide with torque specs I think I can run this over head self. It's joy the most desirable situation but I want to get this truck running again!

Well I've run the overhead twice and there is no change in the amount of smoke that pours out of the stack. I am lost as to what to do. Going to pull the follower covers off and inspect the cam tomorrow night. May use a dial indicator and measure the cam lobe travel at the injector rocker arm, to try to find a bad cam lobe. Other than that we are completely lost.

I have found 3 or 4 different torque values for the injectors. The shop that worked on my pump and injectors told me to torque them to 68 in-lb, an old timer Cummins owner told me 55 in-lb, a manual tells me 72 in-lb, and a forum on Wheels of Time tells me 70 in-lb. So I am even lost here. The first time running the overhead I set them to 68 in-lb, the second 50 in-lb. I looked at the pushrods before running the over head a second time tonight, they all looked straight.

Will try to get a video up if I can.

Have you driven the truck since you put it back together? By drive, I mean run it up to 180-200*.

No, it has not been driven since things have been put back together. My dad and I were talking Monday night after we got it back together the first time, that we hadn't had it to operating temperature yet. We did let it run for a good 15 minutes or so after the first time we set the overhead, the amount of white smoke did not change from when we first started it to when we shut it off.

My dad still has concerns that we have the incorrect pump on it. However, I was told that the incorrect fuel pump will not make a difference in the amount of smoke. Also, when I told the guy at the pump shop what I was doing with the truck, they talked about upgrading the gear drive on the pump, to a bigger drive to supply more fuel. When I dropped the pump off at the shop the guy working on the pump was on vacation but the guy taking my information said he thought it may have the big drive on the pump. Could this cause the smoke issue? Is there an easy way to tell whether I have the big drive or the small drive? Or correct fuel pump?

The guy who rebuilt the pump also told me when he got into the pump it was turned way down. He told me that stock fuel rail pressure was 160 psi and he turned it up to 200 psi. Could this have any effect on the smoke issue?

Here is a link to start up after running the overhead a 2nd time. Injector torque is set at 50 in-lb. There was no change in the amount of smoke from 68 in-lb to 50 in-lb.
[ame="http://s1166.photobucket.com/user/RockinRam96/media/1973%20Kenworth%20W923/IMG_1808_zps31716165.mp4.html"]Start Up After Running The Overhead A 2nd Time. Injector Torque @ 50 In-lb. Video by RockinRam96 | Photobucket[/ame]

Last night we ran the over head again. This time with a different method. We took a dial indicator and found where the cam follower for the injectors was resting on the cam. Which happened to be about the same position as where the previous timing mark would be. I set the dial indicator to "0" and we proceeded. As soon as we moved off the previous timing mark the cam started to lift the injectors. For example if were were at timing mark "C" for the 2nd rotation cylinder #4 would have fired, we set the dial indicator to "0". As soon as we moved off that "C" mark the cam follower started to come up.

We found the maximum height of each injector at set the torque on the injectors at that point. The maximum height of the cam follower happened to be at about 2-3 inches before we actually got to the timing mark. We did this for all cylinders and recorded the amount of lift on each cam follower from resting on the cam to full height. I don't have the paper in front of me but I will get maximum lifts on the cam followers tonight. I do remember, though, that the most travel was 0.114" and the least amount of travel was 0.096". I don't have a spec on the injector lobe lift, but a difference of 0.018" seems like a lot to me. Maybe this is the problem? Which to me points to a worn cam?!

I thought the truck ran better over all, I thought that it started easier and after idling for a few minutes the smoke did start to clear. My dad didnt think what we did made much of a difference and he thought that it may even be skipping. I didn't hear a skip.


Attached is another video. Not sure if it helps at all but may give a vague idea.

[ame="http://s1166.photobucket.com/user/RockinRam96/media/1973%20Kenworth%20W923/IMG_1811_zps4b252e81.mp4.html"]IMG_1811_zps4b252e81.mp4 Video by RockinRam96 | Photobucket[/ame]

Over the weekend we tried a third way to set up the overhead, mainly the injectors. This time we put a dial indicator on the injector side of the rocker arm to measure the injector travel. Previously the injectors were set to 70 in-lb (the torque spec we got from a Cummins Shop Manual).

We ran through the cycle one time to measure the full travel of the injector. We found where the cam follower would have been resting on the cam shaft and then found where the cam follower would have been at the highest point on the cam lobe. Five of the injectors traveled about 0.185", one injector only traveled 0.146".

For the injector that had a shorter travel I had hopes of tightening the adjuster to allow for close to 0.185" of travel. My hopes and dreams were crushed pretty quick. I was only able to achieve about 0.010" more travel before the adjuster bottomed out and had no more adjustment.

Needless to say I put it all back together and made, what I thought, was some improvement. The engine starts up right off the bat, doesn't even roll over one time and it comes to life. Still a little white smoke at an idle, but not terrible, not as bad as it was. My father thinks it has a skip, he is thinking cylinder 4 or 5 but our bad cylinder was cylinder 3. I don't hear a skip but maybe its my virgin ears, and I can't detect that yet.

Next step is to get it all put together and go drive it. We think that maybe a key factor in all off this. Since we have owned the truck, it has not been up to operating temperature. And it may just need to get some cob webs worked out after sitting for at least 7 years.

Here is another video for anyone who is interested.

[ame="http://s1166.photobucket.com/user/RockinRam96/media/1973%20Kenworth%20W923/IMG_1817_zps50ef8bb4.mp4.html?sort=3&o=0"]IMG_1817_zps50ef8bb4.mp4 Video by RockinRam96 | Photobucket[/ame]

Well I may have a line on a late Big Cam. Should know more tomorrow sometime the overall condition and exactly what the motor is, but may be the future for this truck.

Watching this. I want to do an old KW and find a way to throw a k19 in it

Is the K19 different than a KTA 1150?

If so you don't have to find a way to fit a K19 in a Kenworth. The KTA-1150 was put in over the road trucks from the factory. I know Peterbilts, Kenworths and possibly Internationals and Freightliners came from the factory with a KTA 1150 in them. Extended or long hood of course.

Here is a KTA 1150 in an A model KW
Jerry Hairhoger pulling his Kenworth at Mercer - YouTube

K19 is a KTA1150

Kta1150 is what they called the one that went into trucks.

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Yeah I've only ever know it as a KTA 600 or KTA 1150.

I know where there is a Kenworth W900A with a KTA 1150 in it, but the guy will probably never sell it for a reasonable price. I would love to own the truck.

RockinRam96 said:

Is the K19 different than a KTA 1150?

If so you don't have to find a way to fit a K19 in a Kenworth. The KTA-1150 was put in over the road trucks from the factory. I know Peterbilts, Kenworths and possibly Internationals and Freightliners came from the factory with a KTA 1150 in them. Extended or long hood of course.

Here is a KTA 1150 in an A model KW
Jerry Hairhoger pulling his Kenworth at Mercer - YouTube

Click to expand...

I know they produced them but usually buying a. Truck with one in it is not cheap at all. That truck looks a out right

Yes most of the time finding a truck with a KTA in it is expensive. I can't imagine buying a truck and finding a KTA some where else would be cheap.

As far as I know, the A model long hood KWs only came with a KTA or Cat 3408. A long hood A model is a bit longer than a plain A model, and those big motors are stuffed in the ling hoods damn pretty good.

There have been a couple of standard hood come up for sale with KTs in them, and you could spec almost any engine you wanted in a long hood, prolly the least likely engine to find in an extended hood would be a 8V92, but they say there are some out there.

RockinRam96 said:

Over the weekend we tried a third way to set up the overhead, mainly the injectors. This time we put a dial indicator on the injector side of the rocker arm to measure the injector travel. Previously the injectors were set to 70 in-lb (the torque spec we got from a Cummins Shop Manual).

We ran through the cycle one time to measure the full travel of the injector. We found where the cam follower would have been resting on the cam shaft and then found where the cam follower would have been at the highest point on the cam lobe. Five of the injectors traveled about 0.185", one injector only traveled 0.146".

For the injector that had a shorter travel I had hopes of tightening the adjuster to allow for close to 0.185" of travel. My hopes and dreams were crushed pretty quick. I was only able to achieve about 0.010" more travel before the adjuster bottomed out and had no more adjustment.

Needless to say I put it all back together and made, what I thought, was some improvement. The engine starts up right off the bat, doesn't even roll over one time and it comes to life. Still a little white smoke at an idle, but not terrible, not as bad as it was. My father thinks it has a skip, he is thinking cylinder 4 or 5 but our bad cylinder was cylinder 3. I don't hear a skip but maybe its my virgin ears, and I can't detect that yet.

Next step is to get it all put together and go drive it. We think that maybe a key factor in all off this. Since we have owned the truck, it has not been up to operating temperature. And it may just need to get some cob webs worked out after sitting for at least 7 years.

Here is another video for anyone who is interested.

IMG_1817_zps50ef8bb4.mp4 Video by RockinRam96 | Photobucket

Click to expand...

Pull the push tube for that injector, it could be bent just a little. I think I have one if it is, I will have to look this weekend, if that isnt the case it could be that the cam follower has collapsed, it is not common for a 855 to wipe a cam lobe.

I hung a new charger on my big cam this weekend, its is kind of a hybrid, but started as a HT4B that had a chewed up compressor wheel, I had a HT80 backing plate, wheel, and cover just laying around so I decided to see if I could make it work. It is a tight fit on the manifold, the overall diameter is close to an inch bigger than the standard HT4 cover. The wheel went from a 86/127mm to a 88/139mm. I gained around 5psi, but is a little slower to come to life.

The injector push rods are all straight (as of last time I ran the overhead). I ran the overhead about 2 weeks ago and I pulled the push rods out to check them and they were all straight.

I have been told by numerous people that the small cams had a tendency to wear the cam lobs down causing excessive white smoke. I was told the hard surface wears off the cam, then the softer metal under it wears much more rapidly, causing the motor to smoke progressively worse, quickly.

I found an early mechanical 330, N14 a farmer had in his grain truck that I am going to buy. This farmer bought this motor to haul grain and the cab and dump body rotted out on the truck so they scrapped everything but kept the motor and trans, still in the frame. The sealed everything up and wrapped it in plastic. He just wants to get rid of it and asking $500 for the motor, and guarantee it to run. With the little potential of power from this small cam, the potential of this N14, and the cost of buying the N14 vs putting a new cam in the small cam, the N14 just makes much more sense.

I agree on the N14 thing, though with a little wiring a 525 N14 Celect would be pretty bad ass! I have a pic somewhere of a signature 600 (full electronic CM570 ISX) in an 85 359 pete. The wiring actually isn't too bad at all.

N14 is a tough engine to beat though, I've seen many Watkins (now fedex freight) N14s come down for preventative overhaul at 1.1-1.3 million only to find parts inside that had a lot of life left in them!

Will

I was really hoping that this N14 was going to be electronic, but turns out its an early mechanical N14. I agree thought, I don't think it would be bad to put an electronic N14 in a truck either. I cant imagine there is more to it that just getting power to the ECM since the ECM is a stand alone ECM (I believe) on the side of the bock. Last weekend at Antrim Diesel Days there were quite a few older trucks with electronic motors in them.