Oil viscosity

[69_Sport]

The viscosity needed for adequate oil pressure is not mentioned in any of the above comments, yet that is likely the most important consideration.
One should run the thinnest oil possible that gives adequate oil pressure once warmed up.
One size does not fit all. Each engine is different, with internal clearances and wear determining the pressure.
If you are worried about which oil viscosity to use, yet you don't have an oil pressure gauge, you are already in over your head.

 

[Ether]

Anyone using the Joe Gibbs DT40 in SBF's? It's all the rage in the sensitive late 90's/2000's Porsche 911 circles. I use it in my 911, and the oil analysis from Blackstone has been excellent.

I saw the Joe Gibbs break-in oil mentioned, so I was just wondering. It's $$ but supposedly has some of the best protection out there.

 

[Steve83]

The viscosity needed for adequate oil pressure is not mentioned...

That's because it's impossible to know or measure or calculate or plan for.

...that is likely the most important consideration.

Not really since there isn't 1 pressure in the engine. It varies by where you measure, under what conditions. The pressure near the pump (where the sender port is) is not the same as the pressure in the cam bearings, or the pushrods, or the distributor, or... The farther you get (by oil path) from the pump, the lower the pressure will be.

If you are worried about which oil viscosity to use, yet you don't have an oil pressure gauge, you are already in over your head.

You're contradicting yourself. Since you already said that even YOU can't tell someone what his pressure should be, what good would it do him to know any pressure?

The fact is: it's just not that precise OR critical. If you have 10psi, and the engine is running OK, that's good enough. If you have 60psi, the oil is probably too thick to flow out where it needs to go. If it's somewhere in between, it'll probably last a while, depending on a million other factors.