Oil relief pistons and springs

[Taylor]

When I had my motor on the Dyno last week,  my oil pressure
 was a little lower than I would have liked.  Here is what my oil system consists of,  Berg 30mm pump, full flow through an oberg,  stock oe springs and stock oe pistons with NO groove.  I ran the motor with Lucas 30wt break in oil and a berg 3.5 sump.   At 5000 rpm I have about 69psi but consistently by 7000 I had 55psi.  It was a gradual drop through the sweep.

So... am I the only one who doesn't use the grooved piston? Also I think the oil is adequate so should I put a booster spring and plug in the rear.  If the drop continued I would only have 50psit at 7500.  Any suggestions?
Taylor

[neil68]

I never use a grooved relief piston...always use two solid pistons, as per the late German dual relief cases.  Also, have Berg 3.5 sump and Berg full-flow kit (Geers filter), so I don't think that should be a factor.

Maybe try some different springs, even though you have OEM springs at present?

I prefer 5W30 or 5W40 oil myself for better flow...

[stealth67vw]

Now that it's getting warmer, so is my oil temp. My engine had a hard time getting to 170F but the last few weeks I've got it over 200F and my oil pressure drops down to 5 or 6 psi at idle with a pressure of 40 lbs at at 5000 and 55lbs at 7000, in fact it won't go over 60lbs even when dead cold. I''m running 10W-30 Valvoline VR-1, a Berg 26mm pump, FF cover and System 1 tall filter, Berg 3.5 qt. sump and non grooved plungers and OE springs. Last week I tried the grooved pulley side plunger but it didn't really change anything.

[richie]

Taylor I pmed you

cheers richie

[dangerous]

Sounds to me like your sump may be getting a lttle low and drawing in air.
I never use anything larger than a 26mm pump, because they empty the sump faster than it can get back.
I would go back to a 26mm pump, or even 21mm.

Those wide sumps also thin out the layer of remaining oil, so it will draw air earlier.
You can improve the system by moving the "bell" down lower,
but it will need to be smaller in diameter (36hp)so you can still get the sump on.

The heavier springs, or longer pistons will increase the system presure,
but it will not help if the presure is dropping away at high rpm, due to air mixig with the oil.

[Taylor]

Sounds to me like your sump may be getting a lttle low and drawing in air.
I never use anything larger than a 26mm pump, because they empty the sump faster than it can get back.
I would go back to a 26mm pump, or even 21mm.

Those wide sumps also thin out the layer of remaining oil, so it will draw air earlier.
You can improve the system by moving the "bell" down lower,
but it will need to be smaller in diameter (36hp)so you can still get the sump on.

The heavier springs, or longer pistons will increase the system presure,
but it will not help if the presure is dropping away at high rpm, due to air mixig with the oil.

Maybe you are right about that as I noticed that when we turned it over for oil pressure (no valvetrain or spark plugs,) that we could only get 12psi.  I don't think anything is wrong with it as it was spraying oil all the way up to the rocker boxes.  I think it was due to the lifter bore bushings having the groove in them, which in retrospect, I don't think is necessary.  I have the the 30mmoil in there in preparation for a front mounted oil cooler, so maybe when that is installed I will need to add a booster to the flywheel side relief spring.

[Taylor]

I have now decided that, after looking at my Dyno sheets, everything is actually pretty good.  I noticed that actually it was when we made pulls with less than 15 min in between that the oil psi started to drop.  On pulls with more than an hour everything was good.   I might put a booster plug in for a slight increase but that's it.