-> oil viscosity. But I never saw a real answer as to what viscosity to
-> use on a V8.
Use whatever gives you at least 15-20 PSI at hot idle - that is, as hot
as the car is likely to get, sitting in summer traffic or at the track.
That's the lowest pressure the engine will ever see. The pump's flow
increases pretty much as a function of RPM; just off idle the bypass
valve opens and starts bleeding excess oil. The engine's oil
requirements are relatively constant; they go up a bit with RPM, but
not enough to ever be a factor considering the pump's excess output.
Viscosity has little to do with lubricity; a water-thin oil can often
be a much better lubricant than jelly-thick stuff. However, if you have
large clearances the engine might be noisy with low-viscosity oil and
quiet with the high-viscosity stuff.
Any thicker than what it takes to keep hot idle and (maybe) quiet
running, and you're just wasting power pumping sludge through the bypass
valve.
-> How about synthetics?
I like synthetics, but I don't like the extended drain intervals some
of the manufacturers like to promote. As long as you have some
reasonable change interval (3 to 10 thousand miles) it doesn't really
matter what you put in there. If you have a real problem inside the
engine, about the best you could hope for by playing with oils is that
you might get a few more miles out of it before you have to fix it.
==dave.williams@chaos.lrk.ar.us======================================
I've got a secret / I've been hiding / under my skin / | Who are you?
my heart is human / my blood is boiling / my brain IBM | who, who?
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