07DominatorSS

20 at idle and about 40 running using AMSOIL SERIES 2000 Racing Oil.

BryanTuvell

50 to 55 under load, as low as 20 after a long run, 45 minutes at 3800 to 4500 RPM. I use 20-50, whatever is on sale at advance, usually Penz or Valv.

03 496 HO's 210 hours. Oil changed way to often.

Great thread though.
Bryan

Knot 4 Me

25 PSI if just cruising about 3,400 RPM. Closer to 20 PSI if running above 4,000 RPM. I've always felt the motor had great oil pressure compared to my prior 454 motors.

Raylar

Knot4 me:

I assume those figures are from your dashboard analog guage. If your real oil pressure is at 20psi above 4000rpms under load the Mercury guardian system would normally sound an alarm and put you in a reduced engine pwer level. You should check the engine oil pressure either with a mechanical guage on the engine or a scan tool reading the ECM oil pressure output and verify the real oil pressure. If you oil pressure is really 20psi above 4000rpms you possibly have a real oil pressure issue and I would not recommend placing loads on the engine with that kind of pressure at those rpms!

Best Regards,
Ray @ Raylar

07DominatorSS

"OIL PRESSURE" is so overated these days. The real concern someone should have is OIL VOLUME. Just because you have high oil pressure does not mean you have good lubrication for the critical parts of the engine. Think of it this way, if you used a 50wt oil and pushed it through a straw as opposed to a hose, it would have more pressure, but not more flow, therefore less oil through the system. That is why a lot of auto manufacturers require synthetics in their cars now, ie. Cadillac, Dodge Vipers, Corvettes, all commercial airlines and so on and so forth. When you use an oil that flows better, or is less viscous, you create less pressure, but more flow, therefore better lubrication. When you have 0 pressure, that is when you should worry.

Jeff P31

Pressure is what the wife gives you , volume & flow is what the girl freind makes happen !!!!!!!!!!!!

Vinny P

My pressures seem to be higher than most here. I have a new mechanical guage, so no real chance the #'s are off. I run 15W50 Gold Cap Mobil 1. At speed, I see 60-70 lbs. After a hard run, it never dips below 30 lbs. The engine ( an NA 540 ) has about 100 hours on it.
I am surprised tht nobody else has mentioned what they are running, so I guess I'll start... I am running a high volume Melling pump with a Teague 10 quart pan, a 3" x 18" Hardin cooler with a Hardin thermistaticaly controlled filter head. My concern is that the oil temperature goes to near 300* on hard runs. I replaced the oil thermistat with the same results. I am thinking that I should not have rigged my water pressure relief valve before my oil cooler. I have the pressure regulated to 30 psi, but I see a fire hose of water dumping out of the thru hull fitting at speed. Now before someone says 30 psi of water pressure is too high for my gaskets, I have closed cooling. The sea water only gets in the coolers, heat exchanger and headers.

Raylar

When you expierence 0 oil pressure in a high performance marine engine, you are passed worry, you should start counting the money in your wallet to see if you have enough for the repair!
I agree that volume is an important component in an oil system but it is also a part of the pressure since trying to push a certain volume of oil through an orfice or against resistance is what determines the pressure measured. Good oil pressure means that a good volume of oil is trying to overcome resistance to flow a certain required volume of oil in an engine that will provide enough oil barrier between rotating surfaces of bearings and journals and such and that enough oil is traveling to points within the engine to remove heat and cool components. If the Merc 496 or most big blocks were designed to flow large volumes of oil at low pressures then manufacturers would list normal operating oil pressure ranges at much lower values. I have seen thiese type of systems work in other engine families especially big diesel engines, but I have yet to see the 0-20PSI oil pressure operating range marine high performance BBC engine!
Whenever I hear a analogy being made between the uses and condtions in todays street vehicles and those for marine high performance engines I know the analogy is flawed. When you really understand the load and demand differences between a marine high performance engine being operated at 4000-6000rpms under load for periods of in some cases a half and hour at a time there is absolutely almost NO COMPARISON to a street driven high performance engine with its lighter weight synthetic oils and greatly reduced load times!
I will almost absolutly guaranty that if you have a stock Merc 496 engine that is making a REAL 20 psi oil pressure at 4000rpms under load.
YOU HAVE OR WILL VERY SHORTLY HAVE A SERIOUS MECHANICAL ENGINE PROBLEM !!
If someone here can demonstate to me that on this particular stock engine you can operate this marine engine under load for any extended period of time at this 20psi @4000rpm load use I will be all ears! I never stop learning everyday and I am a good listner!
In the mean time if you have a BBC marine performance engine operating at 4000rpms under load with 20psi measured oil pressure, you need to quickly verify your guage readings are correct and if they are, stop using the engine and find your problem before your wallet gets lighter!!

Best Regards,
Ray @ Raylar

Knot 4 Me

Ray, I was answering the question of what my oil pressure is at idle after running above 4,000 RPM for an extended perod of time. As I stated towards the top of this thread, my oil pressure is above 50 PSI when running at speed under load. I would never run a motor that was only showing 20 PSI at 4,000 RPMs.

PatriYacht

Very true. It is always cheaper to rebuild an engine when you have all of the major parts in rebuildable condition before they start flying out the sides of the block.