N-14 Cummins Experts...Please Step Up

Whatever it is, it don't sound good. Try taking the belt off the A/C first. Can you get someone to start it cold while you listen to everything through a stethescope or screwdriver?

If is was accessory drive bushings it would knock instead of what I'm hearing. I'm using earbuds to listen, and it almost sounds like a worn roller bearing trying to seize. Try the A/C, and if that isn't it, I hope it's not a cam follower roller trying to seize up. That's where I would listen close next.

EDIT: Still sounds like an air compressor to me.

 

Could be air compressor but sounds more like a miss from a fuel injector sticking

 

Nice video, that was really helpful

 

If you pull the front cover, there is the crank gear that drives the cam, the cam gear drives the oil pump, and the accessory drive also driven by the Cam. No idle gear, no bull gear.
Just a thought!

 

Good job with the video!!! The rhythm to me doesn't sound like an injector. I am thinking more a/c compressor or air compressor. Like Stranger said, take all the belts off so you are eliminating the fan and a/c compressor and try again. Internationals had something similar to this years ago where the fuel igniting in the #1 cylinder was being transmitted and amplified through the fan. But that would not go away when warm. Try to unplug that #1 fuel injector and see if the noise changes. Repeat with #2 and so on to help pin point a fuel knock from an injector.

 

Another thought. There is a bearing in the water pump idler pulley . This is often very neglected. When I was in a fleet shop we repacked them annually. It is not hard to do .Just takes a little time. Caution on instaling the cover, once in awhile they will fly off after starting the engine.

 

What I would do is remove the bolts that hold the accessory drive pulley you do not need to loosen any bolts to get it back on and that will cover it all. I use a bar against my skull to listen for knocks and rattles, I have seen an injector have a mechanical failure and over fuel, That was three times period, if you listen at the top of the block you can hear the cylinders firing. Cummins injectors do not have a pintle valve and do drible into the cylinder when shut off. Is there white smoke on start up and it stops when the rattle stops?
If it is not the belts you can remove the exhaust manifold bolts and not disconnect the turbo or the oil line, looking for the cylinder causing the problem.
Just a thought!