vibration damper thoughts

[Poundtowne]

(10-26-2021 )Hammerhead Wrote:  

(10-26-2021 )SquareOne Wrote:  -<snip>-
- If I'm understanding correctly, the fluid inside the damper hardens, therefore it becomes ineffective. Cummins maintenance calls for a 500k replacement, but my question is does the fluid harden because of use or does it have a shelf life? This part I just received for example appears to have been on the shelf for nearly 5yrs according to the stock tag. Would that shorten it's effective lifespan even though it hasn't been installed?

The properties of the fluid cause it to harden from the vibration cycles over time, thus the operational shelf life.
To the best of my knowledge, parts shelf storage life doesn't affect it. This assumption is based on manufacturer's specifying a mileage (hours on a stationary engine) replacement, not a mileage/time service interval.

Theses things get very hot dampening the vibrations, it is the heat cycles on the fluid that determines the service interval.

First, no, the fluid doesn't (usually) harden or become ineffective etc.. If you have ever taken them off and drilled into them (which I have done at least 15 times) you will find that 98% of them have the same consistency. The internal viscous fluid is a silicone based substance that does NOT harden or change based on its exposure to oxygen. What does happen is that the paint chips, the metal rusts, the holes become microscopically oval shaped and the bolts wear away at the dampener. All of this causes the dampener (or harmonic balancer) to become off balance and its ability to dampen the reverberation of the crankshaft becomes less effective. It is a cheap and very effective form of preventative maintenance. I perform them without question at 500k NO MATTER WHAT THEY LOOK LIKE OR WHAT CONDITION THEY ARE IN.