I recently received a nice note from John Machamer about his 1930 Kinner B-5 engine. The factory recommends an oil operating temperature of 122°F to 158°F during cruise conditions.
But John had a problem because his oil temperature ran at only 120°F.
Even after closing off one air inlet he could only get it up to 130°. While this is in the recommended range, it’s still very low. John is concerned he may not be getting proper lubrication in the rear gear cases, and was wondering if a multi-grade or single grade would be better for his engine. [Read more…]