Can I use this oil?

jwoods61us wrote:
Topics like this one amaze me! It is right on par with the tire threads that begin...I ran my tires at 49psi and 66mph for 2 minutes, how badly did I damage them and when will they detonate?.

Viscosity is a function of temperature and film thickness. If anything, a higher viscosity oil has superior wear resistance in severe usage situations. A difference of one viscosity grade will NOT result in an oil related failure.

"Temperature has a big effect on viscosity and film thickness. As a point of reference, one SAE grade increase in viscosity is necessary to overcome the influence of a 20°F increase in engine temperature. At a given reference point, there is approximately a 20°F. difference between viscosity grades SAE 30, 40 and 50. SAE 20 is somewhat closer to 30 than the other jumps, because SAE 30 must be 30°F higher than SAE 20 to be roughly the equivalent viscosity.

"In other words, an SAE 20 at 190°F is about the same kinematic viscosity as an SAE 30 at 220°F, which is about the same viscosity as an SAE 40 at 240°F. This approximation works well in the 190°F to 260°F temperature range.

"If an SAE 50 oil at 260°F is as thin as an SAE 20 oil at 190°F, imagine how thin the oil film becomes when you are using an SAE 5W-20 and your engine overheats. When an engine overheats, the oil film becomes dangerously thin and can rupture."

For a very detailed discussion of viscosity, wear, and fuel economy, click here.

Your premise completely ignores the additive package that results in a multi weight oil.


Read oil talk for dummies at oil talk for dummies

This is an aviation engine page, ( ECI-Engine components inc.) I guess if it works for them it'll work for us.