Higher oil P and component longevity

[JHZR2]

Hi, I have GC (this is not a GC related post) in my 98 S-10. Seems to work pretty well in there, Im happy, and will have to see what the UOA shows many miles out from now. One thing I noticed using this oil, over other oils, even heavier oils (rotella syn 5w-40) is that the oil pressure is higher both at cold startup and full hot idle. Thats all well and good, but I have one question about this. Even though it seems to me that higher oil pressures will provide more lubrication and better protection properties, does running at a higher oil pressure produce more strain/wear on the engine components like say the oil pump? Will running consistently at higher pressures reduce life in stuff like that? Thanks for your input, JMH

 

[Curious Kid]

Good questions... which may go to support the psi/rpm rule of 10psi/K if my memory serves me correctly. It takes increased energy/effort to pump a fluid that's generating any kind of backpressure, but for the most part the side effects of such are to be noticed as decreases in fuel mileage. The lubrication system in an automobile engine (as well as many others that involve pumps) if you will recall, has a safety valve in place which would prevent excess pressures from building, thus preventing excess mechanical loading to the pump's drive mechanisms...and this device is more acurately refered to as a pressure relief/by-pass valve. Such valve failure appears rare, and if anything, might be stuck in the open position. I haven't had any such experience. As far as the oil, well more energy/work is being applied to it, and of which results in an overall increase in oil temperature (if but a few degrees), and a favored condition for fluid shearing I suspect. Because the oil has a relatively short stay within the engine, these conditions to are of little concern. Again, oils are tested and certified for the vehicle user to make things understandible. And in matching the codes along with the vehicle's recommendations per owners manual, it's almost "user friendly". If further curiosity and/or doubt remains, install an oil pressure guage. In the two cars that I've owned, I've done just that, and discovered marginal pressures on one, and rather high sustained pressures on the other. It's all another way of keeping tabs on the condition of things as far as the engine and lube is concerned.

 

[AEHaas]

Oil flow and oil pressure are inversely related. Read my articles, first in the Interesting Articles Section. aehaas

 

[JHZR2]

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Originally posted by Curious Kid: If further curiosity and/or doubt remains, install an oil pressure guage. In the two cars that I've owned, I've done just that, and discovered marginal pressures on one, and rather high sustained pressures on the other. It's all another way of keeping tabs on the condition of things as far as the engine and lube is concerned.

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My truck has an oil pressure gauge, and this is how I know that my current oil choice (GC) produces higher pressures at both cold startup and full hot idle, compared to other oils, even heavier ones! JMH

 

[JHZR2]

quote:

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Originally posted by AEHaas: Oil flow and oil pressure are inversely related. Read my articles, first in the Interesting Articles Section. aehaas

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I understand the fluid dynamics of the process. My question is more related to the wear and tear on a piece of equipment, say an oil pump, due to the higher rate of 'deadheading' (I suppose we can quality it as that), which is related to the higher pressure of the oil due to constrained flow through n orifices that provide x total flow area. I dont think many people wear out their oil pumps, etc., but thats what I dont know. Also, is the oil that cools and lubricates a cylinder pressurized? Or, maybe as a better way to phrase it, will a higher pressure coming out of piston cooling oil jets, etc., have a higher chance to slip by portions of the oil control system around a piston (rings, etc.), and contribute to use? This all comes back to engine design, which I dont know too much about. Thanks, JMH

 

[AEHaas]

The pressure in any oil pump is limited by the high pressure pop off setting. I do not think that any oil at any pressure will result in pump failure before it’s time. The main wear in oil pumps is from dirt in the oil. Remember that the pump gets the oil from the sump bottom and sends it the the filter NEXT. If your engine is dirty wear on the pump will be accelerated. Good oil, fuel and air filtration is necessary. Remember that the main coolant for the piston and bearings is the oil. High end, high BHP engines will have jets at the bottom of each cylinder, the main function is to cool the hot piston. There is evidence that thin oils cool better. Thin oils are also thought to allow more blow-by but other studies show a better seal with thin oils. Some thin oils increase oil consumption while others of the same viscosity decrease oil consumption. Experimentation is needed with different oils in your engine for your testing in your application. Do not be afraid to go one thicker or one thinner but going 2 grades thinner as I have been doing takes a lot of work to follow what is happening. You have to make sure one is deriving the benefits sought, and at the same time minimize wear. aehaas

 

[ebaker]

I broke the oil pump driveshaft in my Tiger (302 Ford) by running too hard with thick cool oil. High pump pressures can also pump the pan dry quicker in a high G cornering situation. Some engines need higher pressure pumps to overcome design defects/restrictions in their oiling systems also.