Originally Posted by
peterh337
I don't think that - if your only engine instruments are oil temp and pressure - normal readings on those are a good guide to a good engine, because in a Lyco the oil pump is a constant volume (gear) pump which feeds a spring loaded pressure regulator valve which will maintain a constant-ish pressure over a fair oil temp range, and the oil temp itself will take a long time to rise, if at all, if there is a localised mechanical problem such a bearing about to seize.
A friend of mine had a spun bearing in a Continental O 300 which has basically the same type of oil system as a Lycoming. He said the oil temp went from normal to pegged in less then 3 minutes with the oil pressure dropping to the yellow
. He headed to the nearest airport and landed about 10 minutes later with the engine knocking badly. Halfway through the landing roll as the aircraft slowed the prop stopped
. The engine was removed for overhaul but was replaced as there were virtually no salvageable parts left.