Cummins NTC-350

No not really. We go to maybe one or two pulls a year that they separate the classes out by horse power but that's it. Most the time everyone runs in the same class. Yours didnt do to bad. 4th?

What does that red A model have in it?
 
I think I was 8th, there was a bunch of us packed in together. The top three are all electronic and were trailered in. The A model has a 3406 mechanical in it.

I should have held mine to the floor, I was no where close to being at the rpm I needed to be at, but I underestimated the initial weight of the sled.
 
That A model is sweet. But I'm partial to the A models and W900s all together.

Yeah when I pulled my dads W900, 3406B I always tried to ease into the pedal and have the pedal flat on the floor by 100 feet, give or take a little base on track conditions. Most of the them before 100 feet and it would just spin out, after 100 feet it just wouldn't pick up the RPMs.

Who knows what this little Cummins will do. But I have a cam coming within the week. , going to put that in and hope that it runs quite a bit better. I reset the overhead by the Cummins procedure Saturday and it seemed to run much better.

How do I get some more fuel out of this pump? When the new cam goes in I want to add some more fuel and we are going to add a little bit of timing while we are in there.
 
The pump is easy, but will need to come off for some of the work. I will try and get you some pictures of what and how to change some things.

Timing will help a bunch especially with the way that small cam is timed from the factory, set it between .070 and .080. Then you could have your injectors reworked.
 
Thats fine if the pump has to come off. Everything is going to have to come off anyways to put the cam in. Surgery starts tonight! I am going to have to take the pump and air compressor off to get to the cam followers.

I don't think I'll have my injectors worked on for this season. I'll just add what fuel I can with the stock turbo. Over the winter I'll send the injectors out and have them reworked and opened up, along with an HT60.
 
Cody, you find any pics of operating on the pump? Going to a pull this weekend and I'd like to get into the air fuel ratio settings. It could use a little more response.

I got a cam in last week, over the 4th of July weekend we are going to put the new cam in it. Hoping to have the followers out Monday night so, if one of them are bad, I can get it on order.
 
Well we can completely disable the afc or we can just open it up a little depending on what you want to do.
 
I'm just looking for some more response out of it. I still want the AFC operational to be driveable and not fog out every intersection. But as it is now there is a bit of a lag, it seams.

I'd like to be able to know how to play with it so I can get it where I like it.
 
Okay, its nothard to do and can be done on the truck. I dont know if yours has the tin cover around the throttle shaft, but if it does that can leave. The AFC adjustment is the allen set screw right above the throttle shaft, loosen the jam nut and back the srew out for better response, you can tune this till it suits you.

When you get the pump off, you will need to drill the ball out of the end of the throttle shaft, the fuel pressure scew is behind this ball, the adjustment for this is to also turn it out, I set mine by taking the screw completely out and then three full turns back in, but you wont need that much pressure yet, i would go three turns out from where it is now and then plug the hole with some silicone.

The button and spring pack are located at the back of the pump under the gear pump, there is a cover that looks similar to a bell that has four quarter inch bolts in it. You will see a tube with a snap ring in the end of it, under that is the spring and shims that control rpm, under the spring pack is the piece that holds the button, it also has your idle adjustment screw on it, try not to turn it if you can.

I think I remeber you said this pump came from a shop, if so have them get you a number 5 button and see if they can get you some shims as well. I could make you a 00 button if you want or you could do it yourself, its up to you. I think the 5 will do everything you want to do.

I will try and get some pics again, I forgot to get them last weekend.
 
My pump has the round tin cover over the throttle shaft, not the pentagon shaped tin cover. I have had it off before just out of curiosity to see what was under it but the only thing there is high and low idle settings. There are two long adjuster stops to adjust throttle travel.

On the throttle shaft there is a cap, not quite sure what is under it. There is an adjuster inside this shaft, under the cap that will adjust rail pressure? As far as the buttons and RPM go, I am sure I can call the shop that worked on my pump and have them fix me up. The guy who rebuilt the pump told me that he set the pump to "fuel to 2,100 rpm." So does that mean the pump will cut fuel back at the rpm, or does that mean that is all the motor will turn?

Either way, when it all comes apart I will be doing some scientific research!
 
Hmm, I'm not sure about your afc adjustment, could you maybe get a picture.

On the rpm setup, yours is set up so that when it is under a load it will turn 2100, the free rev is a little higher, you can go to 2600 under load without any issues.
 
Picture of the pump.

99519a4b-26f1-47e0-8272-12540e69429c_zpscbb4f200.jpg
 
Well hell, that is an old housing for a PT pump, I don't know if we can get any adjustment out of the back side to make a difference or not.
 
But the do have a limiter or bypass that is controlled by the intake pressure, I can only assume that is the best way of describing it, I know that by moving the spring to the outside of the diaphragm to hold it in makes a huge difference in low end fueling, prolly to the point that it isn't good for the engine.
 
There is no air signal to that pump. I remember back in the day there may have been a limiter up on the intake someplace.
 
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