N14 Rattle front drive

Does it almost sound like the engine's labouring a bit when it happens?

 

That kind of sounds like what a buddy of mine's N14 is doing. I never got to dig into it because he was busy. Would be curious if his has the same issue.

 

Same basic set up as the NTC. Some of those sounded like they were grinding rocks. Saw some people through a lot of money at them and never make it go away. If the air compressor is not timed properly can cause and or exagerate this. If the accessory drive is not worn I would just run it. Wonder if that can be excessive gear backlash. You only hear it when the air compressor is pumping and or the a/c is on. Both units load and release the accessory drive. When the fan comes on it provides constant load to the drive and the noise stops. Thats my story.

 

Check and make sure all bolts that attach the fan blade are there and tight. Then check belt tension. If accessory drive was bad, your air compressor and fuel pump wouldn't be working. If the accessory drive seal is out you would have oil slung all over. And if that seal is out, chances are you need a new front cover because the brass bushing is coming out, and they are pressed in the front cover. No fixing that bc once they move, it shuts off the oil galley. If you do need a front cover, 4 states in Joplin has aftermarket for $300. They are $1200-$1500 at cummins. I know, bc I put one in within the last 6 months.

Sounds to me like fan could be loose or warped a little, belts could be too loose or too tight, ac compressor could be going bad, look for metal shavings around it.

 

I have heard a lot of N14 engines rumble like this when the A/C is on. The higher the pressure goes the more of a grumble it makes. I always contributed it to the weak A/C compressor mounts that a N-14 has.

 

I would argue some of that but the belt is a very good point. Especially if it is made with notches in it. I have seen some of those make a lot of noise and they were not loose.

 

If the fan is tight, check the fan clutch. The old air apply Hortons would wear the spline out on the center hub and let the fan move back and forth making a nasty rattling noise. Put air to it to engage the clutch and give the fan a good tug each way. If the fan moves back and forth a bit without the pulley moving (and the fan bolts are tight), the center hub splines are worn out.

You can see the splines that I talking about in this pic:
http://kitmasters.com/productimages/7500hp.jpg

 

Kit master is the way to go if replacing fan clutch. I think it's a much better system. That's what I replaced mine with, very happy and easy to do yourself. Good post GrapeApe