fatherlarry
10-02-2002, 04:38 PM
Bob sent me this to post, any questions, ask Bob.
Viscosity Specifications
I have attached the most recent SAE J300 specifications on engine oil viscosity limits. As can be seen, the W specifications are determined at low temperatures. The CCS (Cold Cranking Simulator) viscosity limits are established to insure sufficient engine cranking speed during startup for the particular grade and reported in centipoises (cP). The MRV (Mini Roto Viscometer) determines if an oil will flow to the pump (yield stress in pascals} and how well the oil will flow once the engine starts (centipoises). The high temp limits are determined at 100 C by kinematic viscometers and reported in centistokes (cSt). There is also a high shear viscosity limit, which reports viscosity at ten to the six recipical seconds and reported in cP. This simulates viscosity at high shear areas such as bearings and piston rings.
Please feel free to contact me if you have any questions.
Regards
Bob Pache
:nod:
Viscosity Specifications
I have attached the most recent SAE J300 specifications on engine oil viscosity limits. As can be seen, the W specifications are determined at low temperatures. The CCS (Cold Cranking Simulator) viscosity limits are established to insure sufficient engine cranking speed during startup for the particular grade and reported in centipoises (cP). The MRV (Mini Roto Viscometer) determines if an oil will flow to the pump (yield stress in pascals} and how well the oil will flow once the engine starts (centipoises). The high temp limits are determined at 100 C by kinematic viscometers and reported in centistokes (cSt). There is also a high shear viscosity limit, which reports viscosity at ten to the six recipical seconds and reported in cP. This simulates viscosity at high shear areas such as bearings and piston rings.
Please feel free to contact me if you have any questions.
Regards
Bob Pache
:nod: