408 oil pressure issues

[Infecteddog]

Background- '72 360 based 408 with newer oil pump/pickup, 360 car pan and dipstick, '98 magnum heads with a hydraulic roller.

Hot oil pressure gets low. It's been a few years since it got together and it hasn't seen many miles but it looks like I may have painted the oil filter mounting plate as I think I found paint flakes down there. Motor sounds better and quieter than my low miles 3.6 so I suspect no engine damage. I think we have a high volume pump in it so I'm thinking the Canton Racing plate may help resolve my issues but I wanted additional input. I was able to pull the adapter fitting with a 3/8 extension after I nicked it up some with a 12 point like a fool. I may pull one from a 340 or another 360 I have or replace the fitting. Looks like the old gasket is still hanging out there, but I have the Canton to replace the adapter. Mostly I'm curious if there's something else I may be missing causing the drop in hot oil pressure. I did not have a gasket/washer between the bolt and plate though.

 

[Ironracer]

What kinda oil Ya runnin'? It is kind of common for lower viscosity oils to thin out when up to operating temperature especially in hot climates.... Do you have a mechanical gauge on there and
what are you reading on it?

 

[Infecteddog]

What kinda oil Ya runnin'? It is kind of common for lower viscosity oils to thin out when up to operating temperature especially in hot climates.... Do you have a mechanical gauge on there and
what are you reading on it?

Have a mechanical guage, had the issues with 10w40 and have had the issues with 10w30. Reassembled it with nylon bushings on both ends of the oil filter adapter fitting and will soon test drive it to see if I still am having the same issues once hot.

 

[Ironracer]

Have a mechanical guage, had the issues with 10w40 and have had the issues with 10w30. Reassembled it with nylon bushings on both ends of the oil filter adapter fitting and will soon test drive it to see if I still am having the same issues once hot.

Right on! May be a big difference there! I'm running 2050 but I'm down here in Tampa Bay it gets pretty damn hot but I still run about 185 when warmed up it'll creep up a little bit at a red light but it drops back down. I've noticed the oil pressure drops a little bit when it gets up to operating temperature but not bad the main thing is to watch that gauge when you're giving it gas and to make sure the oil pressure is going up with the RPM. That and obviously too low of a pressure'd scare the snot out of me anyhow!

 

[Infecteddog]

So it still drops back down when hot. Quite possibly one of the most notable observations is that when a filter is fresh, I can easily get 60+ psi. After a few minutes, I will drop pressure and 40-45psi is about the max I'll have from then on. This is an F body with 2.45 gears so 5000rpm even is rare. I do have hollow oil-thru pushrods. Oil never has any signs of coolant.

 

[GTX JOHN]

40 to 45 is not terrible for that engine depending
on the bearing clearances and type of pump.
In the old days we tried for 10 Lbs. per 1000RPMs.
Not so much any more.
I have had issues with Fram filters the last couple of years
with them dropping the pressure significantly. I will no longer
use Fram filters.

 

[Infecteddog]

I steer clear of Fram filters. I try using Purolator most of the time as I have comfortably put like 100,000 miles on their filters in the last 6 years across my drivers. Thanks for making sure to add that point to the list, as I want to be sure I am not leaving anything out. As stated, warmed up I get down to about 10psi at idle and it will pick up in throttle but not above 45psi. Also of note, the oil pan is the stock 360 C body oil pan that I have used since we put the 360 in it over 10 years ago- no windage tray and a stock replacement pickup.

 

[GTX JOHN]

You can drop the pan and install a High Pressure Pump
that is made by Mellings as I recall. First I would go
to a higher Viscosity Oil.