Oil does leak down from the system, be it galleries or filter, the longer it
is left parked. The quality of the oil filter has a major impact on this,
but even switched off fully hot and left for a few days my V8 bearings were
still swimming on oil when I removed the big ends and main bearings, so to
say they are 'dry' at start-up is definitely not correct. That engine is
notorious for low oil pressure and a slow rise, the factory moved the gauge
tapping from the output of the oil filter to the output of the pump in order
to allay customer fears - but making absolutely no difference to the
bearings of course, even so even when just left overnight it takes several
seconds for the gauge to even start rising, and takes maybe 10-15 seconds to
reach full pressure. Left overnight the roadster is pretty
well-instantaneous to register pressure, after a couple of weeks or more it
is about five seconds from the start of cranking, having fired up after 3 or
4 seconds.
15 seconds to see oil pressure is way too long. Can you hear the knocking
straight away? Or only after a few seconds of running and before pressure
builds? If straight away it's likely that worn bearings are the cause of
the slow rise. If only after a while then it's likely that the residue of
oil on the bearings is being lost before oil is available again, and that is
causing bearing wear.
PaulH.
----- Original Message -----
> ... Result: no oil in the main gallerie untl the engine runs a bit, the
> passages fill up and the pressure comes up to normal. You hear the almost
> dry rod bearings rattle until they get oil.
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