RalphVa
Super Member
- Joined
- Dec 19, 2003
- Messages
- 7,885
- Location
- Charlottesville, VA, USA
- Tractor
- JD 2025R, previously Gravely 5650 & JD 4010 & JD 1025R
I posted this on the miata.net forum, but so many of you seem to be almost superstitious about oils. Here's a good site that explains about engine oils.
https://www.minimania.com/Motor_Oils..._Misunderstood
He pretty much says those bar charts in our owner's manual are wrong for putting an upper ambient temperature limit by oil grade, as the temperature in the engine is set by the coolant thermostat unless the engine is under very heavy load. Then the oil temperature is what is important, not the ambient temperature.
However, he痴 dead wrong about the effect of cold temperatures on stored oil. He is ignorant of wax. I spent 31 years in all areas of lube oil manufacturing (except hydrocracking) with the world's leader in lube and wax production. Removing wax was one of my areas of expertise.
Wax formation in oil does not ruin the oil, as he states. It'll just melt when the oil warms up and remixes with the oil again. Wax by itself is an EXCELLENT lubricating oil, probably on par with synthetic oil. HOWEVER, it will solidify at temperatures as high as summer time mid day in Death Valley. If you kept the engine running all the time in ambient temperatures to keep the wax from solidifying in the crankcase where the oil pump is, you'd be fine. A 110-120 F melt point wax would probably even be a good track oil (e.g. that kitchen wax).
He does say that at high loads that you can use even 5 or 10 grade oils IF your oil pressure is at or above 75 psi. This is from his statement that F1 cars operating at 15,000 rpm use straight 5 and 10 grade oils. Apparently at those high revs, they have no problem in maintaining 75 psi oil pressure.
I've had many vehicles that run maxed out at about 45 psi on the oil gauges. These would not be good race cars, and they're also pumping way more oil that is needed (e.g. round and round via the relief valve): hp pumping oil that could be used to make the vehicle go faster on the track, in the case of a tractor to do more work.
Ralph
https://www.minimania.com/Motor_Oils..._Misunderstood
He pretty much says those bar charts in our owner's manual are wrong for putting an upper ambient temperature limit by oil grade, as the temperature in the engine is set by the coolant thermostat unless the engine is under very heavy load. Then the oil temperature is what is important, not the ambient temperature.
However, he痴 dead wrong about the effect of cold temperatures on stored oil. He is ignorant of wax. I spent 31 years in all areas of lube oil manufacturing (except hydrocracking) with the world's leader in lube and wax production. Removing wax was one of my areas of expertise.
Wax formation in oil does not ruin the oil, as he states. It'll just melt when the oil warms up and remixes with the oil again. Wax by itself is an EXCELLENT lubricating oil, probably on par with synthetic oil. HOWEVER, it will solidify at temperatures as high as summer time mid day in Death Valley. If you kept the engine running all the time in ambient temperatures to keep the wax from solidifying in the crankcase where the oil pump is, you'd be fine. A 110-120 F melt point wax would probably even be a good track oil (e.g. that kitchen wax).
He does say that at high loads that you can use even 5 or 10 grade oils IF your oil pressure is at or above 75 psi. This is from his statement that F1 cars operating at 15,000 rpm use straight 5 and 10 grade oils. Apparently at those high revs, they have no problem in maintaining 75 psi oil pressure.
I've had many vehicles that run maxed out at about 45 psi on the oil gauges. These would not be good race cars, and they're also pumping way more oil that is needed (e.g. round and round via the relief valve): hp pumping oil that could be used to make the vehicle go faster on the track, in the case of a tractor to do more work.
Ralph