Posted By: Junky
Oil Pressure vs High RPM's ? - 03/11/11 06:43 PM
My 383 runs about 20+ psi at idle with a a hot engine (180 to 190) and 52 psi at 6,000 RPM's. Am I starving the engine of oil at 6k? It's a Milling street pump. Running 15W40 oil.
Can someone explain pressure vs volume?
Posted By: stumpy
Re: Oil Pressure vs High RPM's ? - 03/11/11 06:45 PM
Pressures are fine don't worry about it.
Posted By: Pacnorthcuda
Re: Oil Pressure vs High RPM's ? - 03/11/11 06:47 PM
Thats a little low for 6,000rpm but still adequate.
With 15w40 oil I am thinking you have somewhat loose clearances, meaning its easy to flow oil through the block/rods etc and hard to build pressure.
You might want to try a HV pump (NOT HP), the HV pump will flow MORE oil per revolution, and therefore have an easier job building pressure.
Posted By: mike s
Re: Oil Pressure vs High RPM's ? - 03/11/11 07:00 PM
At 6000 rpms the pressure would have to be less than 35 to literally starve the engine.That is it would be the minimum to overcome inertia per bearing size.However the pressure is low for 6000 rpm.10 psi per 1000 rpm is a safe minimum.Somewhere you are leaking pressure.
Posted By: Junky
Re: Oil Pressure vs High RPM's ? - 03/11/11 08:36 PM
Thanks for the assurances guys. I may get a Milodon adjustable pressure relief valve to raise it a tad.
Posted By: Junky
Re: Oil Pressure vs High RPM's ? - 03/12/11 02:17 AM
Cold, warming the engine up at 1700 RPM's the oil pressure is close to 52 psi.
Posted By: ahy
Re: Oil Pressure vs High RPM's ? - 03/12/11 03:34 AM
If its 52 cold, it may just be a regulator spring on the low side of tolerence. The adustable spring may fix it. While I've never done it, I understand its also possible to simply shim up the existing spring with small flat washers.
Posted By: dOrk !
Re: Oil Pressure vs High RPM's ? - 03/12/11 04:10 AM
what size pan do you have ?
Posted By: Junky
Re: Oil Pressure vs High RPM's ? - 03/12/11 07:05 AM
It's a 4 quart pan one that's on a '71 383. I run a windage tray. With new oil filter I run 5 quarts of oil.
20 psi, hot engine, in gear at idle, foot on break. It actually fluctuates from 20 to 25 at idle, since idle is slightly up and down due to the cam. Idle is 750 RPM.
I asked this question because of so many people saying that oil pressure should be 10 psi per 1,000 RPM. It's just always bugged me not having 60 psi at 6k. Don't wanna hurt the engine.
I gotta say I trust RapidRobert and stumpy's opinion.
Posted By: Junky
Re: Oil Pressure vs High RPM's ? - 03/13/11 12:47 AM
Here pretty soon I'll try experimenting with a shim. It's easy to get to. See if I can get it to 60 psi at 6k. I'm just that way.
Thanks for everyone's help.