quote:Assuming they start with a 20w base oil I did not think there would be that much viscosity index improver added to get a 20W50. It's viscosity index is lower than even a 10w30, indicating that its viscosity changes less (from cold to hot) that a 10w30 does, and which leads me to believe it is a pretty stable oil, unless it is poorly manufactured.
Originally posted by TR3-2001SE: I think you are looking for the wrong thing. Most 20w-50 dino oils will be low 40 weight in a few thousand miles if not 30w.
quote:Hot idle or cold idle? Is the engine just old and worn out? All internals "properly" installed? Thought of using a different oil pump? 20-25 at a hot idle though seems fine to me....
Originally posted by Racerjk: Even with 20w50, the oil pressure is not much over 20-25 psi @ idle.