harveyf

True, based on reading forums like Rennlist the oiling system might be the weakest link in what is really a very good engine design. I can hedge my bets at a limited cost with the frequent oil changes and replacing the bearings with the engine in the car every other winter is also cheap insurance. And no problems to date, knock on wood. Note this engine lives near the redline most of the time so it is a harsh but accurate test of Porsche engine reliability.

Regarding engine condition, I would point out that the bearings are designed for the normal rod tension/compression loads with some safety factor. If your engine for instance was suffering detonation, you would be seeing increased rod compression loads, perhaps above the safety margin and there you go, bearing failure. There are just so many variables that it is hard to really pin down where the problem lies. So I do what I can, cost effectively, and keep enjoying my track time.

harveyf

BTW, my one and only #2 rod bearing failure occurred due the following chain of events: Used engine from a junk yard. I was at a track event. There was a small coolant leak. I really couldn't tell the actual water level in the overflow tank because the plastic was so cloudy. I was on track and concentrating on my driving when we started to get a water spray on the windshield, on a blue sky day. I looked down and saw the temperature gauge in the red. I was less than 1/2 mile from the pits. By the time I got to the pits and was idling I could hear a rod knocking. As best as I can tell, the coolant got low, the head warped due to overheating, coolant got mixed in with the oil, the rod bearing didn't like that, and ker-blam-oh. (I did confirm a warped head when I dis-assembled the engine). So only to my point that 30 year old cars can suffer from deferred maintenance with potentially catastrophic results. I have since purchased a new overflow tank that I can actually see through to check my coolant level.