Dry Sump Oil Aeration

[ashleyd14]

Hi all,

I have a Raceline dry sump kit on my 2.0L Duratec with a swirl tower. It's a C400, track car only.

The engine has just been rebuilt, previously it had a Caterham/Cosworth dry sump which had a scavenge pump failure. I have not run the car since purchase following the issue with the old dry sump.

I have never really paid much attention to the oil in the swirl tower, as previous Caterham's I have owned were run by race teams. I now live in Australia, and imported this car for track days. So, I am doing more of the work myself. I have noticed there is a lot of aeration in the oil in the tower. Is this usual? I have read all the instructions on oil levels (5mm below the baffle when warm after running), and I understand the wall of death and the baffle should reduce aeration but I am still a little worried. See the photos.

Is this normal? Keen to get some feedback from people who would know what it should look like.

[DCL]

The scavenging pump will pumping oil and air when the sump is sucked dry, so it's not unexpected for the oil returning to the tank to be aerated. It's a sign that the scavenging has the capacity required to remove all the oil.

The difference with the Cosworth design is that it is a two stage scavenging pump that collects from front and rear of the sump so always has some oil to pump. The Raceline pump is a single stage that only collects from the rear of the sump. So under breaking it may only pump air.

I think it'll be unlikely that the oil feed back to the pressure pump has any significant air in it. So I wouldn't be too concerned, but clearly the more oil in the system there is, the more time there is for the air to separate out.

[ashleyd14]

Thanks, I very much appreciate the response and the explanation.

I have taken some photos of the oil that I have pumped from the bottom of the swirl tower. There is a lot of aeration. From these do you think it is sucking too much air? It's a new engine and has running in engine oil in it.

[ashleyd14]

Another pic

[DCL]

Those pictures do look odd, particularly if that's from the bottom of the tank. I'd investigate it further before using the car. That sort of foaming suggests the crank is being immersed in oil.

Was the oil filled to the engine rather than the dry sump tank for example? If it's got good oil pressure I try leaving it to get hot and see if it settles down.

If not then things to check would be the sump has been assembled correctly - the windage tray, the core in the pickup passage in particular, and obviously the 'in' 'out' hoses are the correct way round to the tank.

[ashleyd14]

Thanks again for the reply.

It was filled from the oil tank.

Having spoken to Raceline again, it seems my tank is somewhat different to most. It has only 1 breather on top, and it's on the wall of the tank rather than in the middle. I am going to get a new tank with 2 connections, 1 in the center and 1 towards the edge and connect them to the crank breather and catch tank as they describe.

After that I agree, the sump will have to come off and see if it was put together correctly.

Will post an update once I have it fixed!

Appreciate the support

[mickrick]

Watching this thread, as I just bought a dry sump kit for my 2.0 Duratec, but not a Raceline one. I'll be interested to see what tank you have, and what you replace it with, as I'm researching dry sump tanks right now.
I wonder if that single stage scavenge pump is taking the oil away quick enough? the oil looks like it's been frothed up by the crank?