496 Oil Pressure
09-21-2008, 01:27 AM
#2
Emerlad Coast PwrBt club
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oil pressure
What are you getting? after my motor is nice and warm, its very close to 20, and as RPM's go up i get around 30-35, maybe 40. And yes i know its LOW, I dont like it, however, Im told, MERC. minimum is like 3 PSI, and 10 PSI for every 1000 RPM's.
I know the Oil pressure sucks and Im very curious to know why its low, but at this point i just wanna run.
As for oil im runnin castrol GTX 20-50, Im planning to switch to Mobile 1 15-50 synthetic, anyone know if this weight is ok to use?
I know the Oil pressure sucks and Im very curious to know why its low, but at this point i just wanna run.
As for oil im runnin castrol GTX 20-50, Im planning to switch to Mobile 1 15-50 synthetic, anyone know if this weight is ok to use?
09-21-2008, 08:26 PM
#4
Charter Member #1055/Moderator
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20 at idle, 40 at higher rpm's with Mobil 1 15w50. I'd like to see a little higher, but it is normal for these engines.
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09-22-2008, 08:57 AM
#6
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15W50 Mobil 1. 50 + PSI running. About 25 PSI at idle at normal operating temp. 205 hours on motor. If I run hard it will dip down to 20 PSI at idle until the oil temp drops some.
09-22-2008, 11:20 AM
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What's the correct oil pressure for a 496 Merc?
The determiner on oil pressure in most healthy big blocks and especaily the 496 Merc is oil temperature. If you are running on the hose idling with the coolant temp up to 150 to 160 degress you should se about 40psi idling and about 50-60 psi at 2500 rpms. If you have been out running at higher rpms in warm water and air temps at 4500 to 5000 rpms you will see about 20-25 psi oil pressure when you first pull back to idle until the oil temp starts to drop back from about 225 to 230 degrees F. its been running at.
The pressures at 4500 to 5000 rpms with this hot oil should be about 50-55 psi under load. If you operate your boat hard in poker runs or for extended periods above 4500 rpms or boat in high temperatures or high water temps I would reccommend changing out the 8" stock oil cooler to a 12" unit which will hold the oil temps down a bit and help with warmer higher continous rpms effects on 496 oil pressure.
We sell this cooler and it is configured to fit right in place of the stock cooler without re-plumbing the system for those that are borederline on oil temp with a 496 or have made significant HP upgrades.
If you are seeing 20-25 psi oil pressure and 35 -45 psi oil pressure just on the hose, you may have some mechanical issues,bearings, pump, etc and you should be careful if under warm load the oil pressure does not increase to the 50-55 psi range at 5000 rpms.
Its also assumed that your analog guage is reading correctly or it compares closely with the ECM oil pressure readout on a scan tool or laptop software.
It goes without saying that good correct weight oil is also a must , follow the manufacturers recommendations on oil weights and service intervals, oil is cheap compared to engines!
Best Regards,
Ray @ Raylar
The pressures at 4500 to 5000 rpms with this hot oil should be about 50-55 psi under load. If you operate your boat hard in poker runs or for extended periods above 4500 rpms or boat in high temperatures or high water temps I would reccommend changing out the 8" stock oil cooler to a 12" unit which will hold the oil temps down a bit and help with warmer higher continous rpms effects on 496 oil pressure.
We sell this cooler and it is configured to fit right in place of the stock cooler without re-plumbing the system for those that are borederline on oil temp with a 496 or have made significant HP upgrades.
If you are seeing 20-25 psi oil pressure and 35 -45 psi oil pressure just on the hose, you may have some mechanical issues,bearings, pump, etc and you should be careful if under warm load the oil pressure does not increase to the 50-55 psi range at 5000 rpms.
Its also assumed that your analog guage is reading correctly or it compares closely with the ECM oil pressure readout on a scan tool or laptop software.
It goes without saying that good correct weight oil is also a must , follow the manufacturers recommendations on oil weights and service intervals, oil is cheap compared to engines!
Best Regards,
Ray @ Raylar
09-22-2008, 02:12 PM
#8
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It looks like there are at least five people on here with hurt motors. My sonic runns the same 25 lbs oil pressure on the hose at 160 degrees and at idle that it does in the lake at 160 degrees at idle. I guess that make six of us.
09-22-2008, 02:27 PM
#9
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My listed idle PSI is after running. If I am idling out of the marina and get my water temp up to normal but have not ran above idle yet my idle PSI is closer to 40.
09-22-2008, 04:36 PM
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