NTC 350 questions

[dpuckett]

Have an 88 International (not mine, but since I know more than the average local yokle [anything] about them, it has become my project) with a NTC 350 Big Cam III, I think. I'm sure about the NTC350 part, anyway. Million miles, maybe 2k on an out of frame major. Mike, the guy I'm hauling for right now, said the power fell off right before it got rebuilt. They DID replace two injectors. Why not the other 4 is beyond me; maybe injector balance isnt so crucial as it is in our little 6Bs. I asked about the pump, and he said they just put the old one back on. Out of frame major, and they dont even check the pump out? I have noticed that it is about 50HP shy of where it was last summer, when it had a galled cylinder and two bad injectors. Plus, it is SUCKING fuel- 3mpg now vs 4. 5mpg and blue smoke last summer. I am thinking the pump may need taken off and gone through by a GOOD shop, and maybe the other injectors replaced, though I am not really equipped to do the injectors.



What do you guys with more experience think? Is the PT pump as crucial to power and performance as the Bosch pumps on the smaller cousins? I'd think so, but would like other opinions before we tear into it and find the pump up to specs and have to chase other gremlins. This being a farm truck, (and company truck before that) there is no pyrometer, boost of fuel pressure gage, so I cant tell you anything there. It just doesnt pull as well as even the 30yr-old 290 does. I think the shop DID put in new fuel supply and return lines, so that is one thing out of the way.



Thanks in advance.



Daniel

 

[bmoeller]

I'd talk to these guys- http://dieselinjection.net/frames.html

 

[Will24]

Like Dl5treez, start with the valve lash etc, get the injectors tested etc, next step would be checking fuel pressure on the highside of the pump, cylinder pressure, also, make sure that the new fuel suction line is PERFECT, possibly air getting sucked into the pressure pump on the PT unit.





Good Luck

Will

 

[MPalachuk]

It could be in the cam timing, there is a window and if you pick the wrong end it will be doggy. Problem is it is a pain in the ass to time and takes a special tool to do it. If they timed it on number one them matched that on the rest timing can be off on other cylinders. Pump and injectors are also a option.

 

[dpuckett]

Thanks, guys. I also thought of a guy in town that might be able to help with ideas if I can find him in the right mood.



I thought the injectors were cam driven, thus no set pop off pressure? I agree with Dl5treez, not replacing the old fuel system on a major overhaul is a dumb idea. Dont worry, I'm slowly getting word out about who it was, and making the same general comparison to the distributor cap and plugs, so the gasser only crowd gets the general idea.



-DP

 

[fbaurley]

The timing is set by installing thiinner or thicker gaskets on the cam follower box that contains the lifters that actuates the injector push rod. I cant rember whether thicker or thinner will advance, but sometimes it may take a diiferent gaskets in each of the three cam boxexs to get it timed to spec.

 

[MKoth]

What condition are the filters in?

 

[dpuckett]

Fuel filters are new- like new @ overhaul.



I talked to the guy I mentioned today (Bill Lawrence of Missouri DIesel in Poplar Bluff). We may have different ideas of tuning and tweaking the engines, (he thinks if it aint smoking, it aint makin power, which may be true on some of the older models from when he was my age) but we do agree on do it once, do it right, and do what needs to be done; no more, no less. No wonder he's been in business 30+ years. Anyway, he said all the things mentioned here, and then showed me what was needed to set the timing, and that it is basically an all day job for which I am very ill-equipped.



I'm gonna tell the boss, such as he is, that he needs to talk to the guy who did the rebuild and get him to fix it under warranty, or at least get it right. Then we'll work on a pyro and boost gauge to fix up temporary. He has a pyro, I have a spare leadwire (both ISSPRO), and we can use my t-couple for troubleshooting. Boost gauge may be harder to come by... ... If I had those, I could do better in pointing him in the right direction.



I'll update you as soon as I get more info. Think I'll get him to spring for my next TDR susbscription- I'm saving him that much at least... ...



-DP