How quickly should oil pressure come up?

yeah the viscosity profile of the oil across the operating temperature of the motor will differ.

i.e 0w30 will be diffferent viscosity than 5w 30 for the same running temperature

the rateing is based on a test at 0*C and i think 100*C (or maybe 99)

i.e 20W50
20 at 0*C 50 at 100*C

what happens inbetween well....who knows you would suspect a move from 20-50

SAE30 we know it is 30 at 100*C we don't know what it is at 0*C could be 40 50 or solidified beef fat...

but with both

at 150*C well we don't know...they don't tell us.

could be 30 could be 40 could be 60 could be 10 could be 5

some oils fall off a cliff when they are way too hot, some don't

more of an issue on an air cooled engine

experience seems to dictate that after a certain temperature is hit the oil starts to lose viscoity....

given that on a cold morning with 20 w50 i have 20-30 psi at idle i must be in the 20-30 SAE range
but after a long run when engine is hot and the oil should be 50 i have 15 PSI at idle??



all i can assume is the hot oil is less viscouse than the 20-30 i ran on when cold but i would expect it to be 50 but it doesn't seem to be that way, you'd need oil temperature gauge to find out what is going on

dunno where i was going with this..just kinda thinking out load

Dave