1988-02-01

Low Viscosity Oil Studies and the Influence of Radial Clearance on Bearing Distress in a 3.8L Engine 880682

Classical journal bearing equations predict the function of oil flow in dissipating heat, thereby governing the effective viscosity of the lubricant in bearings. From this perspective, experimental dynamometer tests explored low speed, high load, high temperature, operation of four low viscosity oils. Test length was 48 hours using a 3.8L V-6 engine under steady state and cyclic conditions.
With a 1.4 cP HTHSR viscosity oil the bearing distress appeared dependent on connecting rod bearing clearances serving to govern rate of oil flow through the main bearings. Front and rear main bearings exhibited severe overheat-distress. This was related to the design of the oil distribution system in the crankshaft. A severe cyclic acceleration test showed little bearing distress. Significant distress occurred only with an SAE 5W viscosity grade. SAE 5W-30 and 5W-40 multigrades showed no abnormal wear. Results were interpreted in terms of high temperature, high shear rate rheology of the test oils.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Preliminary Evaluation of Octyldithiobenzoic Acid as an Antioxidant in Mineral and Synthetic Oils

2004-01-3051

View Details

TECHNICAL PAPER

CFD Simulation of Connecting Rod Bearing Lubrication

2003-01-0924

View Details

TECHNICAL PAPER

Effect of Oil Aeration Rate on the Minimum Oil Film Thickness and Reliability of Engine Bearing

932785

View Details

X