Oil Aeration with dry sump

[Ted Gerstenslager]

Fresh build, run time 10 minutes. 4.5 crank . .0034 average mains, .0025 average rods
Ran 10 minutes couple of quick whacks, shut it off and cut filter. Lots o shiny stuff.
Pulled it, pulled all the mains and all touched, same for the rods. Not drastic but touched nonetheless.
Only thing I found was the front 2 stages were loose enough to suck air at the pump. Back 2 were tight, a manifold with 3 stages is on the exit side to a #16 hose to the tank, the 4 th stage is ported internally. So the rear 2 have to push oil through the front 2 which are injecting air into the manifold.
8 qts in system.
Would 2 stages sucking air inject enough air into the oil system to cause the failure?
Maybe mr Haberkorn is still around

[BILL-C]

The dry sump stages suck huge amounts of air anyways, so a little air leak on scavenge side makes no difference. The oil tank is where the oil and air get somewhat separated. A leak on suction side of pressure stage would be a problem. I've run into issues with edges of both main and rod bearings (H series narrow race shells) kissing the extra large radii on race cranks many times and extra chamfering is required.

[frnkeore]

As Bill says, only a air leak, on the suction side of the pressure stage, will cause a problem, on the pump, itself but, also check the hose from the tank to the suction side of the pressure pump. I once lost a engine, because something got in the fitting, on the sealing area of the AN taper.

If the tank is round and tall, there should be a problem with aerated, return oil. If it's not a tall tank, a Oberg filter in the return line will help, a lot to get the air out of the oil. It will also be a easy check for metal in the oil.

[In-Tech]

Sorry for the side check, can we still buy Oberg filters and parts? I always liked them but have been using System1 since I thought Oberg closed up years ago.

[dannobee]

Yes, still available. https://www.obergfilters.com/

Racor also made/makes them that look awfully similar if not an exact copy. Maybe Racor bought Oberg, dunno.

[In-Tech]

Thank you, the assembly shows discontinued but I am very glad to see the elements are still available in the 28 micron.

[dannobee]

https://www.jegs.com/i/ZMAX/706/6040/10 ... fvEALw_wcB

Do you need the 8" one? We've used the 6" ones in circle track racing for years.

[Ted Gerstenslager]

As Bill says, only a air leak, on the suction side of the pressure stage, will cause a problem, on the pump, itself but, also check the hose from the tank to the suction side of the pressure pump. I once lost a engine, because something got in the fitting, on the sealing area of the AN taper.

If the tank is round and tall, there should be a problem with aerated, return oil. If it's not a tall tank, a Oberg filter in the return line will help, a lot to get the air out of the oil. It will also be a easy check for metal in the oil.

Yes, tank is tall, holds 8 qts when full to the top. It was a std small Moroso with 4 inches added at sometime and still has the 3 circular baffles suspended from the top.
Going to vacuum test the suction line, and it is pretty stiff from heat and time, so It will get replaced.