oil pressure vs lubrication

[Alan L]

I have read all the postings on oils, and there was a brief general answer to this Q. But I'm hoping someone may be able to be more specific.
When the oil gets hot, the pressure in the system drops. The oil flows easier, and is pumped easier, and probably lost through the clearances easier.
So, at what point is the lubrication compromised. Is it better to run a higher viscosity oil that maintains the highest pressure?
My guess is this would provide less lubrication - slower volume flow, and less flow in the critical bits.
I ask the Q because my race car starts at around 60 psi, and drops to 35 psi at max race conds. I am using 20/50 grade. Would I get better lubrication by running a 60 rated oil, or am I just trading off lubrication while getting a better reading on the pressure gauge.
Thanks
Alan

[Bill Verburg]

Tricky question.

You want a combination of flow volume and pressure. The internal clearances have been designed w/ a certain PVT relationship in mind, with the factory recommended oil.

Lighter oil gives more volume at the expense of pressure, thicker oil gives more pressure at the expense of volume. As long as the viscosity of the oil stays within the design envelope then all is well.

A problem that crops up is that as the engine is used clearances have a tendancy to change.

So you need to determine if the gauge pressure is indeed indicative of a wear problem or a viscosity problem.

If it's a wear problem(likely but not necessarily so), using higher viscosity oil is a bandaid that only gets you so far. The fix is a proper remanufacture of the engine.