Sundyne Gearbox Lube Oil Pump Expected Life 1

[CHoff07]

I'm looking to get a better sense of the life of the internal gearbox lube oil pumps on high speed Sundynes. The local salesman stated that I should expect ~2 years which seems very low to me. I'm not sure if this is their conservative answer to cover any issues one may have or if this part should be considered a standard wear item that needs to be replaced frequently.

I'd like to hear from actual users on the MTBF (mean time between failure) of the internal lube oil pump on Sundyne high speed gearboxes (and any other thoughts you have regarding this matter).

Thanks in advance,

 

[JJPellin]

We have about 75 high speed Sundyne pumps. I have seen about 4 or 5 internal oil pump failures in the past 24 years. This is a gear pump running submerged in filtered lube oil. It runs at motor speed. It should last 20 years. If you don't prime the pump after maintenance or if you don't change the oil and filter every six months, oil pump life will be drastically shorter.

Johnny Pellin

 

[geesamand]

Speaking as someone who designs gearboxes and no experience with Sundyne, we work on the assumption that an oil pump will not last more than a few years. Our customers prefer splash-lubricated designs where practical because it's generally considered that the pumps are less reliable than the gearbox bearings or gears and therefore strongly affect overall reliability.

You might simply take up the question with the manufacturer of the lube oil pumps to see what they advise a reasonable life is, and what a sensible maintenance strategy might be.

David

 

[JJPellin]

The weak point in the Sundyne oil pumps is the drive pin. Sundyne recently changed this from a split roll pin to a coil spring pin. This pin needs to be inspected at all gearbox overhauls. We may be able to achieve such long life with the internal oil pump because we inspect and replace this pin during gearbox overhauls. You should also verify that you are using the current design pump. They changed some of these over the years. In LMV-313’s, I think they went with a larger capacity pump. For the LMV-311 and LMV-322’s, I think that they just added a second drive pin on the end of the input shaft. These should have two pins to the input shaft and a single pin below to the gear case center section.

For other gearboxes, as described by geesamand, I agreed that shaft driven oil pumps are generally a bad idea. But, even with these I would expect 10+ years from the pump. The weak link tends to be the drive coupling. These are often coupled to the end of the bull-gear with a very crude tab-and-socket, steel-on-steel coupling. These need to be inspected at least once every four years for continuous service. Once again, the reliability of the pump depends on proper priming, good oil condition and good filtration


Johnny Pellin

 

[CHoff07]

Thanks for the information and discussion on the pins. This helps highlight where the weak links are in this type of setup.

Location of the equipment will play a big role in how it gets maintained. With the proper maintenance they should last a while but as M&O practices vary between companies and regions of the world drastic differences in lube oil pump life will be observed.

Exactly what I was looking for, thanks!