K-series dry sump oil volumes (suction pump efficiency)

[mcerbm]

I have a retro fitted caterham dry sump on my superlight R. It has the gold pump and bell housing tank. It also has the cam cover breathing ports sealed off.

After reading about the gold pump clucking becasue it has removed all oil and only has air left, I noticed I have never heard this myself and I also had a reasonable amount of oil coming out of the sump during oil changes.

Which made me think how dry is the sump and could i be getting windage on the crank. I know that oil will collect after the engine is switched off and I was wondering if other owners had measured what they remove from the car.

I got:

sump - 1.4L

Tank - 2.8L

Filter - 0.2L

Oil radiator - 0.6l

Its also worth mentioning the pump is back from a titan re-build so should be in fine order. Do these volumes seem correct (especially the sump). 

[OliverSedlacek]

I can't comment specifically on your setup, but in my experience drt sumps aren't that dry! Oil does tend to flow downhill (backwards) from the tank to the sump when the engine is stopped, but the rate depends on the wear on the scavenge pump, the ambient temperature and what sort of slope the car is parked on.

The scavenge pump must have a higher capacity than the pressure pump, but I'm assuming that's not a problem. Race engines often run scavenge systems with 3 to 4 times the capacity of pressure system, The scavenge system will be pumping an air/oil mix under normal circumstances, with the mix varying to keep the levels stable.

[mcerbm]

There isn't a way for the tank to drain to the sump on the caterham system so it would only be the oil pumped around the engine that would drain back to the sump. With the amount that I am taking out I'm guessing I'm not close to having a dry sump when operating. 

[jackb_ms]

When I do an oil change i get the best part of 5-6 ltr of oil out of the systems.

So those quantities seems ok.

I use a suction pump to take the oil out from the bell housing tank

Jack

[mcerbm]

Thanks Jack, do you know how much you get out of just the sump?

[jackb_ms]

No Sorry.

When I do an oil change, I run the engine until the oil pressure drop to 2 bars, which should indicate the engine is nice and warm.

I then more or less empty the oil straight away so the oil doesn't have time to drain back to to the sump.

Jack

[Richard Price]

There isn't a way for the tank to drain to the sump on the caterham system

it drains back to the sump through the pressure pump.

if you were to drain the sump, the moment you stop the engine, you'd get less out of the sump and more out of the tank. 

[Superwhite R283]

Agree with Richard. My dry sump tank level goes down when left for a period. 

[mcerbm]

Ah do you mean the tank level lowers slightly as the oil level seeps upwards past the pressure pump trying to equalise. Looking at the pictures of my caterham sump the oil can only get to the sump after it's been through the engine, there is no communication to the tank other than via the suction pump.

i did warm up the car before the oil change and dumped the sump maybe 2 mins after turning the car off. So I'm thinking it's certainly not dry as the oil won't have drained from the engine that quickly.