What do you mean by “if the engine can be started OK”?
If you pre-heat the oil, you can run on summer oil the whole year round. However, how do you pre-heat outside your hangar?
One of the big advantages of the multi grade oil is that it reaches the parts of the engine furthest from the oil pump much more quickly, the bigger the engine the more this matters.
the thermostat bypass on the oil cooler
The WHAT? Is this a given on all aeroplanes, you think? I am considering adding one, though.
That said, I share the skepticism about “if the engine can be started OK” : define OK? Is the start only ok if the engine fires within one second from the first try?
On a side note, I use Aeroshell Oil Sport Plus Four, as per engine mfr’s recommendation.
Most engines have some sort of oil temp thermostat that should try to keep the oil temp slightly above 180F however the oil cooler will gave a small bypass that lets a small flow of oil pass through the cooler what ever the temp.
This is to prevent “coring” of the oil cooler, this is the total blockage of the cooler due to very cold thick oil preventing the cooler from letting hot oil flow.
For some engine installations this is a big problem because this small flow through the cooler is keeping the oil too cool, on the C152 installation the oil never gets to 180F if the OAT is below 14C. The result of this is engine internal corrosion problems.
I heard recently that it was better to use straight oils if the aircraft was NOT going to be flown regularly because it ‘stuck’ to the engine internals more than the multi-grades; hopefully preventing corrosion.
Camguard should take care of the oil not sticking to the camshaft etc.
Currently I run 50% W80/W80+ and 50% 15W50, Shell. Plus Camguard.
One of the big advantages of the multi grade oil is that it reaches the parts of the engine furthest from the oil pump much more quickly, the bigger the engine the more this matters.
That could be a very good point!
My oil is 165-170F and always has been.
Peter wrote:
My oil is 165-170F and always has been.
It should be over 180°F. 170°F is too low. You might want to adjust your cooler by pass.
I doubht it makes any difference.
Our C150 gets w80 every 50. In the summer we top up with 100 and in winter it gets topped up 80.
The T67M gets 15-50 and again gets topped up with 100 in the summer and 80 in the winter.
Further question I would ask is does straight or dispersent/washing oil make any difference?
There is certainly a large body of opinion within the high utilisation C150/152-type PPL training business that it doesn’t matter what oil you use.
And I can well believe it…
The other Q I don’t know. I now see W80+ sold along W80. What is the difference supposed to be?
I use Camguard anyway; it halves the wear rate on the hard metals. Whether it protects from rust when flying once a week, I don’t know, but for sure a piece of bare steel will be rusty after a week in a damp climate.
Why exactly should the oil be 180F? AFAICS all this achieves is a faster boil-off of any water dissolved in it. So, flying for 30 mins at 180F might be equally effective in this as flying for 45 mins at 165F. But if you always fly for 1hr+ then there should be no difference, and any oil should be more effective at 165F than at 180F… making lubricants work at high temps is always a challenge.
The lubrcation ability so are not in question be is 120F or 190F, the problem is that water and other combustion products mix and stay in the engine, the resultant corrosion speeds the ware inside the engine.
180F is the magic number for boiling off most of the water and avoiding corrosion.
