Re: Lubricants

["David Brister" <david@dbrister.freeserve.co.uk>]

Brian Schlorf wrote:  Having had the luxury of pressurizing an oiling system
without the oil pan on, I can say that the
oil doesn't squirt out around the rods and mains under pressure, it just
sort of oozes out and
drips off, yet the gallery feeding the bearing registers some 50 or 60 psi.
How are we defining
pressure at the bearing?  Is it at the end of the gallery just prior to the
bearing, or is it were
the oil is dripping out the bottom, or is it somewhere else in the middle?

 I think the pressure registered in an oil system essentially will be
governed by the least restrictive orifice. If the oil gallery were punctured
there would be no pressure registered. If all the white metal suddenly
melted from the main and big end bearings, ditto. A good TR engine will
register 70 psi at 2000rpm because the resistance to flow through the
bearings, rockers, various bleeds and so on is such that if there were no
pressure relief valve the pressure would be more than 70psi. The viscosity
of the oil will determine the ease with which the oil can be pumped through
the various bearings/restricting orifices so that has also a major effect on
oil pressure.