Can anyone help with a problem on a Pace Dry sump system that is fitted to a ZX12 powered Phoenix. I have had one engine failure at Mallory Park and a new engine has now been installed. On running the car we found that initial oil pressure was good (40 psi) but when the revs were increased the oil is rising suddenly in the oil tank and the pressure is dropping right down to vitually nothing. Everything appears to be right for the system. The pipes are -12 and the oil cooler is on the scavange side of system as suggested by Pace. We have also tried a new pressure relief valve that has the same effect. Any advice or suggestions would be greatly appreciated!

40 psi at what revs? seems particularly high for the ZX12R given that it should be 23 psi @ 4,000rpm with oil temp at 90 degrees.

Phil

Oil filter and cooler both on output side of high pressure pump. Both should blow through not suck through don't you think?

Hello, The 40psi is at start up when cold. When it runs at fast idle (1200 rpm) with engine oil temperature at 52 degrees (in the workshop) the reading is 20 psi. When the revs are blipped to around 3000 - 3500 then the oil level in the tank rises suddenly and the oil pressure drops to 0. The oil in the resevoir is rising right to the top. The only thing we can think is that it is a problem with the aeration of the oil. Pace have suggested a new resevoir tank but I am not convinced the tank design could create the problem we are experiencing.

What guage are you using? Could it possibly be a faulty guage?

We are using the etb digi dash but have also tested with a normal gauge for a 2nd opinion. The results were the same.

Do you have 2 scavange and 1 pressure fitting on the pump?
Sounds like your sucking the engine dry, and the pressure side is not supplying sufficient oil to lubricate the engine.
Is the tank well vented to allow the oil to be sucked out of the tank to feed the pressure side?
Is the bottom of the tank above the pump?

there could be a problem with aeration. do you have a swril pot in the top of the tank? also, is the tank as tall and then (and baffled) as possible? you won't have oil pressure if there is a lot of air in there due to the compressibility of air and the fact that there is far less oil going through the pump!

The tank is 5" diameter and as tall as possible but this means there is no signifcant height difference between the bottom of the tank and the pump. There is no swirl pot in the top of the tank. I a sure there will always be aeration of the oil due to the way the system scavanges.

well if you won't take it from me, then take it from an f1 engine designer...the two most important pieces to a dry sump system are the pump and swirl pot and the interaction between the two. i am also in the process of designing and researching a pump and matching swirl pot for the s2000 engine at uni.

the oil is getting battered around on its journey through that engine, i believe at the tip of the crank it is being hit at 300 m/s so a lot of the 'oil' you're drawing out is more like fog. i believe pace also use a gear type which causes a little more airation than lobe style due to the meshing teeth (correct me if they actually use lobe).

i'm not pinning down gthe problem solely to aeration (although it looks likely) but it would seem your system does little to combat it at present

We have unwound the pressure relief valve and the pressure at high rpm is improving. Can anyone advise why this would happen? We still have a pace dry sump tank to fit and we are hoping the design of this will reduce the aeration of the oil