jebbear 377 #1 Posted January 6, 2018 When I began reassembly of my K-181S, I noticed something that at first didn't make sense. I believe I found my answer, but I thought I would throw this out there just for opinion/learning purposes. The main crankshaft bearings, which I did not remove as they appear to be in fine condition, were installed with the shielded side "inside" of the crankcase. These were never removed to my knowledge since factory assembly, but I began to wonder how they got adequate lubrication since the shield and the crankshaft itself was blocking the path of the oil to the ball bearings. At first I thought maybe someone before me did re-install the bearings wrong, because my mind was telling me that the ball bearings should be in the crankcase with all of the oil. So I did what all novice mechanics do and went straight to the "Google Machine" and started looking for answers. I found several photos and you-tube videos which I could see the bearings inside of the crankcase on both the plate and block. Then I realized that most appeared to be unshielded bearings which both sides would be open. Anyway, long story short, I was using the Kohler Manual TP-2379 (4/90) as my rebuild guide and source for info, which really did not clarify which way they went. So I dug deeper and went back to Kohler Pub ENS-575 (4-72) which TP-2379 replaced and found my answer. It said to install with shielded side toward inside of block (which is the way mine is), if unshielded it didn't matter. I also found in another Kohler manual (SM-2088) which is not for my engine but similar which stated "Be sure shielded side is up. Ball bearings must not be exposed to engine crankcase oil". After all of this research I went back to my engine and noticed the square keyway in the block and bearing plate which I assume is the intended oil path. So, back to the purpose of my post which is just a learning experience for me, why would the ball bearings not be installed facing the oil reservoir in the block and only rely on the little square channel underneath the bearing to provide adequate lubrication? I'm sure the Kohler designers are a lot smarter than I am and have their reasons, but inquiring minds want to know and thought you guys could enlighten me. Share this post Link to post Share on other sites
oldredrider 2,547 #2 Posted January 6, 2018 The shielded side will "hold" oil inside the bearing. Gives consistant lubrication and assures instant lubrication after engine has been dormant for a while. 2 Share this post Link to post Share on other sites
KC9KAS 4,741 #3 Posted January 6, 2018 58 minutes ago, oldredrider said: The shielded side will "hold" oil inside the bearing. Gives consistant lubrication and assures instant lubrication after engine has been dormant for a while. Well, that makes sense! 1 Share this post Link to post Share on other sites
clueless 2,898 #4 Posted January 6, 2018 1 hour ago, oldredrider said: The shielded side will "hold" oil inside the bearing. Gives consistant lubrication and assures instant lubrication after engine has been dormant for a while. Thanks Paul, for enlightening some of us once again. #oldguyswithanswers. Share this post Link to post Share on other sites
jebbear 377 #5 Posted January 6, 2018 5 hours ago, oldredrider said: The shielded side will "hold" oil inside the bearing. Gives consistant lubrication and assures instant lubrication after engine has been dormant for a while. Thank-You so much for the reply, I guess that does make sense. Even for old guys like me its never too late to learn something new. Share this post Link to post Share on other sites
