Injector Life Expectancy

[in2trux]

(12-01-2016 )Hammerhead Wrote:  

(12-01-2016 )Rig Wrench Wrote:  I've done all 6 in 100k on my 871. I have a theory that at the power level it's at the extended duration is taking its toll. I back up this claim with absolutely nothing, just all that makes since. Started getting a lot of rumputy rump on start up. Checked for bubbles, had on 3 front cylinders. shortly after systems arose again, back 3 replaced and problem solved. Only has just over 100k miles still, total

Help me understand your thought process...

The injectors are cam driven on an 871. (To me) That means that the injector travels 100% top to bottom every second rotation of the crankshaft. There are no electronics on the actual injector, the timing and metering are done externally. The only difference on the injector cycle is the amount of fuel volume in the metered & timing portion of the injector to control timing & injected volume. If I am understanding this correctly, then the engine work load plays zero effect on the number of cycles that the injector should theoretically last.
Yes I understand work/torque load equals heat, and heat shortens the life expectancy of intricate working components like injectors...but besides that, should all else not be equal?
If not, then what am I missing?

What you are missing is the fatigue factor over time to the spring and lag from contamination to the check valves and passages. Add to that cascading effect of wear of timing and metering actuators, flow restrictions from wax build up of contaminates in very fine orifices.
Unless everything is near perfect there is a cumulative effect to the mechanical system.
I assume there is a big difference between new and less stringent reman standards that throw a wrench into the works.

https://youtu.be/_WeiDC6S8Lw