My engine loves high oil pressure

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This is my engine talking; 1. Oil pressure pumps up my hydraulic lifters. 2. Oil pressure sprays oil on the bottom of my pistons, cooling them. 3. Oil pressure operates my cylinder deactivating system. 4. Pressure pushes oil through the filter, cooler and oil galleries. 5. Pressure works against the centrifugal force of the crank and camshaft. 6. Pressure raises the boiling point of the oil. 7. Pressure keeps my plain bearings primed, so they can pump their own oil. I read the list of seven items. Nowhere does my engine say he likes high oil pressure. So the topic header should read: "I love high oil pressure". The rule of thumb is 10 psi of oil pressure for every 1,000 rpm, with a minimum of 30 psi. As RPM increases, the demand for oil also increases, was the logic. After reading through hours of discussion on the topic, I'm worse off now than a week ago. Now what? I'm at a crossroad here.
 
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Well, what is the oil pressure in your engine? Remember that lower oil pressure will allow more flow through the engine and bearings which also can help cooling. There is a nice balance between too high and too low.
 

CT8

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1.the lifters work a little different 2. it is really a fling. 3. yes.Its hydraulic operated. 4.The oil pump pushed the oil through. 5. not exactly sure how to answer that 6.The oil isn't under pressure like the coolant in the radiator. 7. Kinda but the bearings don't pump their own oil.They ride on a wedge of oil some what like water skiing. The engine pressure is determined by the engine design.
 
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High pressure is a result of resistance to flow. A friend of mine had a 1920's Austin Seven, the engine was fitted with an oil pressure gauge. I pointed out that the gauge was reading Zero! He told me that was correct, if pressure starts to show at low RPM it means that the oil-ways are blocked. That engine was designed to have low oil pressure. Older versions had splash lubrication. No Oil pressure.
 
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If your oil pressure is too high, you will bypass the filter more often and run a higher chance of a damaging particle being circulated into the engine.
 
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Originally Posted By: 901Memphis
If your oil pressure is too high, you will bypass the filter more often and run a higher chance of a damaging particle being circulated into the engine.
Not sure this is true. The bypass valve does not open as a function of oil pressure. It operates as a function of pressure differential between the clean side and the dirty side of the media. Since the flow is being held back by the bearings, not by the media of the filter, the pressure should be equal on both sides of the media, both having high pressure, thus a low differential.
 

userfriendly

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I should have put more information down. I've rebuilt a few small and big block Chevs and always used the high volume oil pump that came with a 62 psi spring installed. Some guys would also block the oil filter by-pass with a bolt. Both engines would have .0025-.003 main and rod clearance. In summer I ran 15w40 and winter 5W40. I use the long PF373 equivalent in a different brand. 2006 3500 DuraMax, gave it to my daughter ran 15W40 90% of the time. 2011 2500 DuraMax, straight up is 60 psi on the gauge, during warm-up its over 90 psi. With 15W40 the 2011 runs at 50 psi at 1500 rpm fully warmed up which is 70 mph with 275/65/20 tires. It doesn't matter which oil I put in that engine, at 2,000 rpm the oil pressure is always 60 psi when warm. I have SAE 30 Duron in it now, and the oil pressure is only 5 psi less than 15W40. I'm thinking of trying straight SAE 20 while it is still under warranty and see what happens.
 
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WRT item 7, here's a hydrodynamic bearing, lubricated with air...one of the designs. It illustrates that a hydrodynamic bearing works without having lubricant pumped to it...the "supply" is the ambient air, and the bearing itself does the pumping to drag air into the gap between the surfaces, where it is pressurised by a reduction in clearance (this case a step), and provides part separation.
Note also, that for a given viscosity, surface speed differential is required to provide the full film, and reduction in friction (air is unlikely to hold FM additives in suspension). An alternate design that illustrates the pumping action to full effect are two smooth plates in the same vertical spindle arrangement, with some helical grooves over about 60-90 degrees of arc, which provide ambient air "feed" into the bearing, which then provides the air film due to the different surface speeds (see my grooved bearing top shell discussion of before)
 
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Originally Posted By: tinmanSC
Originally Posted By: 901Memphis
If your oil pressure is too high, you will bypass the filter more often and run a higher chance of a damaging particle being circulated into the engine.
Not sure this is true. The bypass valve does not open as a function of oil pressure. It operates as a function of pressure differential between the clean side and the dirty side of the media. Since the flow is being held back by the bearings, not by the media of the filter, the pressure should be equal on both sides of the media, both having high pressure, thus a low differential.
Agreed, I think memphis is confusing the oil pump relief with the filter bypass.
 
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Re item 1, the spring in the lifter is the lash reduction mechanism, the oil pressure provides the oil to make up the (tiny) volume lost to leakage on each plunger stroke...clattery lifters are due to lifters that have bled down on open cam lobes. Take a SBC, which has around 0.2 square inches of piston area inside the lifter...at 10psi, that's 2 pounds of pump-up over the weight of the lifter spring...60psi, that's 12 pounds of force against the pushrod...not much compared to the spring pressure, and certainly not much compared to the dynamic loads when the valvetrain is in action.
 
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Your oil pressure numbers don't seem bad. My Chevy 454 (stock in a motorhome) runs 55 psi hot all day long on 5w30. Cold might be aroudn 80. My 2.3L Ranger runns 100+ on a cold start in the 30s (f) on 5w20! You get 50 psi at 1500 (70 mph) so I would guess maybe 30-35 psi at idle. However, I don't know much about high performance engines, not sure why they run the thicker oils, except maybe because the tollerences are a bit looser than on a stock engine?
 
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Originally Posted By: Shannow
Originally Posted By: tinmanSC
Originally Posted By: 901Memphis
If your oil pressure is too high, you will bypass the filter more often and run a higher chance of a damaging particle being circulated into the engine.
Not sure this is true. The bypass valve does not open as a function of oil pressure. It operates as a function of pressure differential between the clean side and the dirty side of the media. Since the flow is being held back by the bearings, not by the media of the filter, the pressure should be equal on both sides of the media, both having high pressure, thus a low differential.
Agreed, I think memphis is confusing the oil pump relief with the filter bypass.
exactly. For example, I have an adjustable pressure relief spring in my Melling HV oil pump (Melling part number 10688). i have it set to be just above the hot oil pressure the 289 HiPo engine is capable of producing, so no oil is getting by-passed when the oil is at operating temperature. The bypass is set at 90 psi. The hot oil pressure at speed is 78 to 82 psi, so no oil is by-passed). Z
 
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My Hyundai Genesis Coupe 2L will run 50 lbs at idle when cold and easily hit the 90 lb pump bypass, Even hot the oil sometimes will hit 90 lbs at 7k rpm. No real difference between 5w30 and 0w40 M1 as far as pressure goes. I did see a 5 lb bump when going from a filter with a 30 psi bypass to a 8 lb bypass.
 
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Perhaps your question should be: What could be the Down side of making the highest oil pressure possible. (providing the by pass valve is not bypassing and gaskets and oil filter canisters are not exploding)
 
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Just as a data point, the Firebird in my sig has oil pressure of 70-80 when cold and 60 when hot. This is at idle. When driving it warm, its closer to 70 psi. This is using a hm 10w-30.
 
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Originally Posted By: used_0il
...I'm thinking of trying straight SAE 20 while it is still under warranty and see what happens.
Perhaps what’s ‘best’ for your engines’ lubrication needs and requirements are contingent upon ambient temperatures, particularly given your four-season locale? My stable varies their OE pressures from 100+ to ~50 at redline with stabilized fluid temperature and ~70°F conditions. Our ’31 Model A plugs along okay with barely splashes from its sump (not recommended in more modern iron!). Industry trends are for lower pressures (and resultant parasitic losses) although diesels may be tangentially exempted.
Quote:
Some guys would also block the oil filter by-pass with a bolt.
Wow, maybe hang with different gearheads, eh? smile
 

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You would be hard pressed to find a car owner at a local drag strip that does not block the oil filter by-pass. I asked one owner why he does that; "Are you not worried about your main and rod bearings if for some reason the filter gets plugged, or since you are running 20W50 and the small filter cannot flow enough oil through it for the engine?" His reply was that he was not worried because he takes the oil pan off and checks the bearings after every race. I wrote the part number down of his oil filter and it has an internal by-pass. Other gear-heads are not so lucky. I'm glad someone else mentioned 90 psi on small block Fords, I chickened out. Some Cleveland owners are stretching the pump spring or shimming it to 100 psi. I'm starting to think that all of these band-aid approaches may be a result of most "gear-heads" not wanting to give up their thick oils. Assume your doing everything wrong, and start from there.
 
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