bazhart
Barcelona
- Joined
- 20 May 2009
- Messages
- 1,343
Unfortunately if I start recommending particular oils it seems to open up a can of worms - so I am reluctant to do so - and I am not an expert in tribology only an observer and measurer of sizes of engine parts after covering various mileages - of which we have yet seen few Gen 2 9A1 engines to apply that to (which is a good sign of longevity).
However - generally - the Gen 2 engine is better made and although the surface area of the crankshaft shells is still much reduced compared to the older 944/968 models (in common with most manufacturers) - the clearances of the crankshaft shells are tighter than some previous engines - running with a better oil pump and oil pressure control system (raising oil pressures as the loads increase) - and my evidence to date supports my expectation that crankshaft shells will last longer than in the previous models so may well not benefit form a change in oil specification.
However over a long period of time the aluminium that sits at the cylinder bore surface (supporting small nodules of hard silicon) does gradually wash minute amounts away as a result of the oil continually washing against it and this leaves more of the hard silicon particles slightly more exposed than before and more becoming loose. Although the amount is incredibly small the difference may account for the shading you see in older 944/968 models at the main thrust area (where higher mileage ones can eventually seize especially with the 944 S2 which has tighter piston proflies) and so I think a step up to one grade thicker of whatever oil you prefer to use, after say 80K - might well prolong life even more.
Baz
However - generally - the Gen 2 engine is better made and although the surface area of the crankshaft shells is still much reduced compared to the older 944/968 models (in common with most manufacturers) - the clearances of the crankshaft shells are tighter than some previous engines - running with a better oil pump and oil pressure control system (raising oil pressures as the loads increase) - and my evidence to date supports my expectation that crankshaft shells will last longer than in the previous models so may well not benefit form a change in oil specification.
However over a long period of time the aluminium that sits at the cylinder bore surface (supporting small nodules of hard silicon) does gradually wash minute amounts away as a result of the oil continually washing against it and this leaves more of the hard silicon particles slightly more exposed than before and more becoming loose. Although the amount is incredibly small the difference may account for the shading you see in older 944/968 models at the main thrust area (where higher mileage ones can eventually seize especially with the 944 S2 which has tighter piston proflies) and so I think a step up to one grade thicker of whatever oil you prefer to use, after say 80K - might well prolong life even more.
Baz
