Ram Jet

Yep, those hardened polished steel bearing balls and races love a good diet of airborne aluminum silicate. It keeps them nice and shiney. [:-]

Bill

RTK

My Feedback: (1)

Some sealed bearing also come with shaft seal incorporated on them

Eagleburger

Sealed bearings are better in most applications. Doesnt take much to degrade the fine surfaces inside them.

asmund

Lots of good info here and different opinions, that is why we love these forums

After reading through all of this I feel it`s best to just get bearings with seals on both sides and leave them well alone. If it is so that the larger gassers rely upon the bearings to seal the crankcase then this is how it must be.

gkamysz

My Feedback: (19)

First, does the DA really use the bearing seal to seal the crankcase to the shaft? Most of the engines I'm familiar with have a separate shaft oil seal. The Zenoah G20 and non marine G23 and G26 appears (from the manual) to use a sealed bearing to seal the front shaft, but has a seal on the rear shaft. All of the larger Zenoah have shaft seals and open bearings. If you buy the wrong type of bearing for the G20, it would leak. I'm not familiar with DA, and DA does not have a parts list or exploded view in their manual.

I looked at several bearing suppliers technical info yesterday just to make sure I'm not crazy. None of them said sealed bearings are truly sealed, and only NMB said their sealed bearings are greased "for life".