Terry great answer but how do you ascertain " minimum required viscosity for the application that is maximized for the application in viscometrics AND more importantly chemical composition to provide that protection, sealing,stability, heat transfer, and most importantly lubricity?"
Q: does heavier oil really help in summer?
- Thread starter meep
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By circulating through the engine via the oil pump!
There! we agree.
From what I've seen over the past year - with temperatures around 30 degrees f in the winter oil temps hover around 180-190 degrees f. At say 80 degrees f ambient summer temps, the oil may hover around 200-220 degrees f. I have no oil cooler other than the sump surface area and what's able to sink through the engine block.
In cooler ambient air when stuck in traffic, the more or less stagnant air around the sump is still able to take some heat away via convection I suppose, where as sitting over a black, sun-heated roadway is of less thermal differential, so per given quantity that moves around the sump, less heat it can take away. I suppose that temperature differentially induced air flow/convection would also lend to greater activity in the cooler ambient air and less so during hotter periods so as to play with cooling rates and thus maintaining an overall cooler oil temp per.workload, etc., while as has been said the coolant temp remains within a narrow window year round thanks to a thermostat, radiator, and thermostatically controlled cooling fan. Similarly concerning air flow when traveling down the road at a given speed, however induced by the motion of the vehicle/engine/sump through the "ocean" of air.
Any change in temp. has an effect on oil viscosity, albeit less so as it approaches "normal" operating temperatures. So to it has thus far been said that oil's temperature also effects additive activation rates, namely ZDDP's IIRC from some recent reading. Shifts in operating temps also effect fuel and moisture burn-off rates, oxidation rates, and rates of volatility which it has been questioned whether actually base oil constituents and/or additives.
Though I can't argue with the sense that the push to use lower oil viscosities at operating temps (20wts vs.30's, etc.), with cafe goals, I might also think that such as increased the willingness to manufacture engine surfaces that require lubrication with higher finish qualities, lowering asperity peaks and enabling the use of lower viscosities without an increase in damage. Of course there's an increase potential for damage from foreign material in circulation to breach the minimum clearances within the narrowest of gaps within a journal, so overall cleanliness before final engine assembly and the utilization of quality filters that spend less time in bypass are key. So to is the overall state of cleanliness in operation as far as air filtration AND for the oil during the OCI.
Take care.
In cooler ambient air when stuck in traffic, the more or less stagnant air around the sump is still able to take some heat away via convection I suppose, where as sitting over a black, sun-heated roadway is of less thermal differential, so per given quantity that moves around the sump, less heat it can take away. I suppose that temperature differentially induced air flow/convection would also lend to greater activity in the cooler ambient air and less so during hotter periods so as to play with cooling rates and thus maintaining an overall cooler oil temp per.workload, etc., while as has been said the coolant temp remains within a narrow window year round thanks to a thermostat, radiator, and thermostatically controlled cooling fan. Similarly concerning air flow when traveling down the road at a given speed, however induced by the motion of the vehicle/engine/sump through the "ocean" of air.
Any change in temp. has an effect on oil viscosity, albeit less so as it approaches "normal" operating temperatures. So to it has thus far been said that oil's temperature also effects additive activation rates, namely ZDDP's IIRC from some recent reading. Shifts in operating temps also effect fuel and moisture burn-off rates, oxidation rates, and rates of volatility which it has been questioned whether actually base oil constituents and/or additives.
Though I can't argue with the sense that the push to use lower oil viscosities at operating temps (20wts vs.30's, etc.), with cafe goals, I might also think that such as increased the willingness to manufacture engine surfaces that require lubrication with higher finish qualities, lowering asperity peaks and enabling the use of lower viscosities without an increase in damage. Of course there's an increase potential for damage from foreign material in circulation to breach the minimum clearances within the narrowest of gaps within a journal, so overall cleanliness before final engine assembly and the utilization of quality filters that spend less time in bypass are key. So to is the overall state of cleanliness in operation as far as air filtration AND for the oil during the OCI.
Take care.
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