So David Hardcastle says
> . ... The Rover V8 does not like modern
> lightweight oils, in fact 5W-50 oil could, under certain circumstancs
> be detrimental to the engine. Thin oil cannot be pumped in volume in
> the same way as heavier oils, although the pressure will be
> maintained.
>
How can it maintain the pressure against what would appear to be the same
(Or lower due to thinner oil) system restrictions if it isn't pumping the
same or greater volume?
Heavy (20/50) oils are fine for worn engines and "fast and loose" racing
engines but unnecessary for and detrimental to most road engines. Even tuned
ones. If you are making adequate (per the manual) oil pressures at working
rpm's then your engine is receiving adequate lubrication. If your oil
pressure is low at idle but normal at higher revs even this is OK, just
means that your lube system is low restriction (worn maybe) but adequate
volume is coming from the pump because when the revs rise so does the
pressure. Another question is of course what is idle. My 3.9 will idle at
350 rpm with 5 psi or less oil pressure when hot (190F, 10/30 GTX) at a more
reasonable 700 rpm the oil pressure is 15 psi rising to 35 psi at 2500 and
not going any higher because the relief valve has opened. It reaches maybe
45 psi when cold.
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