N14 Cracked the Compressor shaft 3 times!!

This is weird. Where is the break occurring? I can't tell by the story you have written. When the shaft breaks is the pulley falling off because the shaft broke infront of the gear or does the air compressor no longer turn because the shaft broke behind the gear? If the pulley half breaks away I wonder if the belts are too tight and flexing the shaft. If the compressor half is breaking I wonder if the compressor is getting hydraulically locked with water or coolant on top of the pistons. There really isn't much else that shaft drives. Is this unit still running the original compressor? Is the rear of the compressor bolted the bracing and the bracing bolted to the block?

 

Yeah, Air compressor is gear driven and when shft fails, fuel pump does not send fuel to cyl. head and engine stalls

 

i think i would replace the balancer, sounds like its had a hard life.....

 

The accessory drive shaft is breaking in front of the bushing. That I have never seen and I worked on then for many years.
The harmonic balance is for the crank, I was involved with a test where we put on a huge accessory pulley to speed up the fan and it burnt the belts off in one day never hurt the shaft. That is a large shaft 7/8" Cummins should be able to look at it and tell you why it broke, flaw, machining, to hard, what it is. I would take the pieces to a dealership that has a teaching facility and get the to send it to Cummins Engineering and get there opinion. They have some really good guys that should be able to give you an explanation.

 

Well, I am going with belts too tight without seeing this engine.

 

Seeing as there is a lot of Cummins enthusiats around, please assist me with this dilema. I am about to make a decision on the following engines.
1. Cummins Big CAM IV - 400 HP
2. Cummins N14 Celect Plus - 430HP
3. CAT C12 - 430HP and
4. Detriot Series 60 - 430HP.
Which of these engines would you pick and why?

 

if you can post some pics that would be great.

 

you need to contact cummins tech support. not your local cummins guys. They should be able to help you a little more.