I have been leasurely reading articles on the aspects effecting gasoline engine longevity. I am only looking at engines that have no particular problems in design. In the past I would have said that the limiting step would be the rings. As the aged engine wears compression lessens. Now it seems that engines are designed in such a way that all parts have about the same longevity under normal use. Interestingly the vehicle size is not important as the smallest car or largest SUV will have about the same like span (if well kept). Engine displacement and the number of cylinders is not a factor as far as I can tell.
Living in extremely cold and hot environments, especially hot and dusty locations is very important. Cold environment wear goes along with the thought that most engine wear occurs before the oil is fully up to operating temperature. Many dispute this but the evidence is overwhelming to me including SAE papers on the topic. It concerns me enough that the start up oil viscosity at 75 F is the most important criteria that I look for when selecting a viscosity range.
Others will argue that as I live in tropical Florida I could be running straight, non multigrade oils without concern. And that I could run 40, 50 or even 60 grade oils and expect less wear with each thicker grade. I always use the multigrade oil that best matches my engines operational needs, most often thinner oils. And I have shown that the wear as measured in oil analysis is normal or below normal despite using what some would claim could only ruin my engines.
A prominent recurring theme was engine cleanliness. And maybe this is the most important. Keeping the oil and incoming air clean is the most commonly mentioned item. This goes against the grain in many ways. People are going 10,000 and 20,000 miles on their oil using brands advocating this behavior. And many will tell you that leaving the oil and air filters in longer actually makes them better. They say the dirt will eventually fill the large pores and only the better filtering smaller holes will remain. I would have thought this. Yet the analysis of oil tests has led me to change the air filter twice as often as called for in the owners manual. I believe the air filtration is more important than oil filtration. And though I do not live in a dusty environment there is certainly more dust in the air at this hot tropical location.
Sump temperature. This is also a recurring theme. While bursts of throttle will not heat up the sump a constant high load will do so. Towing big loads up mountains in mid summer will hurt. It will not cause catastrophic wear but rather accelerated wear. That is to say more wear than usual. In general things that run hotter wear more. It begs the question. Under normal loads thicker oils run hotter. Would you be better off using a thinner oil and run cooler as I always do? Wear analysis in my engines support this theory.
I am currently running another 3 year experiment to test this theory again. In the 812 Superfast I will soon analyze the 5W-40 Ferrari spec’ed oil. Then I will run a 0W-30, then maybe a 0W-20. The final leg will be the original oil and viscosity. In all unfairness I will not be taxing the oils the same. I have always waited for the thicker oils to come up to full temperature before running around the town with bursts to redline. Currently 170 - 175 F to 9,000 RPM.
I have always run the thinner oils up to full RPM before reaching stable operating temperatures. Currently the Ferrari oil has a viscosity of 80 cSt at 104 F whereas the 20 grade RLI oil I may be using (and used in other high performance cars) has a viscosity of 44 at 104 F. The hypothesis is that cooler running high RPM engines last longer than hotter running engines, despite using thinner oils.
ali
Living in extremely cold and hot environments, especially hot and dusty locations is very important. Cold environment wear goes along with the thought that most engine wear occurs before the oil is fully up to operating temperature. Many dispute this but the evidence is overwhelming to me including SAE papers on the topic. It concerns me enough that the start up oil viscosity at 75 F is the most important criteria that I look for when selecting a viscosity range.
Others will argue that as I live in tropical Florida I could be running straight, non multigrade oils without concern. And that I could run 40, 50 or even 60 grade oils and expect less wear with each thicker grade. I always use the multigrade oil that best matches my engines operational needs, most often thinner oils. And I have shown that the wear as measured in oil analysis is normal or below normal despite using what some would claim could only ruin my engines.
A prominent recurring theme was engine cleanliness. And maybe this is the most important. Keeping the oil and incoming air clean is the most commonly mentioned item. This goes against the grain in many ways. People are going 10,000 and 20,000 miles on their oil using brands advocating this behavior. And many will tell you that leaving the oil and air filters in longer actually makes them better. They say the dirt will eventually fill the large pores and only the better filtering smaller holes will remain. I would have thought this. Yet the analysis of oil tests has led me to change the air filter twice as often as called for in the owners manual. I believe the air filtration is more important than oil filtration. And though I do not live in a dusty environment there is certainly more dust in the air at this hot tropical location.
Sump temperature. This is also a recurring theme. While bursts of throttle will not heat up the sump a constant high load will do so. Towing big loads up mountains in mid summer will hurt. It will not cause catastrophic wear but rather accelerated wear. That is to say more wear than usual. In general things that run hotter wear more. It begs the question. Under normal loads thicker oils run hotter. Would you be better off using a thinner oil and run cooler as I always do? Wear analysis in my engines support this theory.
I am currently running another 3 year experiment to test this theory again. In the 812 Superfast I will soon analyze the 5W-40 Ferrari spec’ed oil. Then I will run a 0W-30, then maybe a 0W-20. The final leg will be the original oil and viscosity. In all unfairness I will not be taxing the oils the same. I have always waited for the thicker oils to come up to full temperature before running around the town with bursts to redline. Currently 170 - 175 F to 9,000 RPM.
I have always run the thinner oils up to full RPM before reaching stable operating temperatures. Currently the Ferrari oil has a viscosity of 80 cSt at 104 F whereas the 20 grade RLI oil I may be using (and used in other high performance cars) has a viscosity of 44 at 104 F. The hypothesis is that cooler running high RPM engines last longer than hotter running engines, despite using thinner oils.
ali