BusyLittleShop, I truly believe you're trying to bring about helpful and useful information to other members of this site, but unless you go into great detail or provide links and references that members can further study and look at, much confusion can and will result.
I haven't come across any members that have stated that they believe when a 10W40 shears down to a 10W30 after an OCI in their wet clutch motorcycles that they believe the size of the oil has changed. Between a 30 and a 40 grade oil there is a difference of 3.2 cSt, and what causes this difference in cSt and the time differentiation between the two in the capillary tube viscometer test is due to the THICKNESS IN VISCOSITY. Gravity has nothing to do with this; this is why gravity is utilized as the "constant" in this test, because gravity will have the same effect and force on any item, whether it's in bringing a bowling ball or a golf ball being dropped off the roof of a building, they will both hit the ground at the same time even though their weight and physical dimensions are different. Gravity will likewise have the same effect on either a 30 or 40 grade oil, and the only thing that alters how long it takes to move from the starting to finishing position is the THICKNESS/VISCOSITY OF THE OIL.
To recap, when a 10W40 shears down to a 10W30, the oils viscosity has dropped and the oil is not as viscous. This then can have a detrimental effect because the oil film can rupture in critical areas of the engine and gearbox because it lacks as much oil film strength in these highly stressed areas. If you are to again reply to me, please reference the entire post and the references you plan on debunking instead of quoting single sentences that leave out all the pertinent information and references.
Originally Posted By: BusyLittleShop
Originally Posted By: Analyzer
Please make an attempt to check your facts beforehand so as not to confuse new/other members
People are confused... I think we can do a better job educating what
we all know is true... like when we say the oil sheared 3 cSt, new
members think the oil size was reduced by 3 cst... my point is a 3 cSt
is the result of a gravity flow test... thinking in terms of flow and
not size we can all make more informed choices in oil...
Understanding a 3 cSt change in viscosity is measured by noting the time it takes oil to
travel through the orifice of a capillary under the force of gravity... its not a size measurement...
