Relocating oil pump pickup hole

[AC sports]

In my efforts to build the ultimate wet sump for the Fiat twincam, I have struck another dilemma. My design now features a winged, trapdoor sided oem modified unit, but I want more.
Originally the car has 1 engine block mounted breather that feeds into a block mounted air / oil separator. The separator then has a tube going back to the sump to dump oil from the mist, and a hose going to the intake or in my case catch can for the fumes/ air.
The oil drain tube exits near the oil pump. Indeed the oil pump has its intake hole drilled to one side and close to the return tube. I assume this is to use the oil pump suction vortex to help suck oil out of the separator.
Problem is that with this offset oil pump pickup hole, the oil pump pickup gets uncovered and sucks air on left turns as it's not in the centre of the sump.
My question is: how critical is this oil pump suction on the air /oil separator given I want to relocate the hole to the middle of the pump and hence sump.
In pic you can see what I mean. OEM its drilled in the red zone. I want to drill it central and to the black. You can see the oil return pipe on the left of the pick up.

[dwilliams]

Move the pickup opening to wherever it's most likely to stay in oil. For that matter, you can bend or relocate the whole pickup if that's what it takes.

[jed]

XX2

[ProPower engines]

If this is a road race type engine useage then build a swinging PU tube.
There is several examples on the net to look at. the other option is build a oil pan with a recovery pouch to catch oil as it
comes off the crank and directed into a well baffled sump off set to allow the PU to be covered in oil at all times.

The gates and baffles must be made to allow for oil direction to the PU as it drains back to refill the sump.
Its a good time to add a windage tray and aeration screen to the pan as well as oil pumps better then air does.

[AC sports]

The actual oil pump pickup is aluminium and cant easily be moved. Only the hole in the cover can be moved as in the picture. From originally the red position to the black position. If you look at this in relation to the oil drain tube to the left you see its moved away about 3/4 ". My question was will there still be enough suction from the pump to pull the separated oil back to the sump given the extra distance.
The tube is already up against the pick up, so cant be bent any closer.

[ProPower engines]

Probably not.
But I do not see why the PU can't be modified from stock. Aluminum pumps are easy to weld on the cover plate like this pump uses. Yes it needs to be tig welded and the tube is thinner and you need a tight radius bending die to get the job done but I see no issue. Done this 100ès of times with old ford pumps that used an aluminum body for marine engines.

But if all that tube is allow upper oil to drain back to the sump I would be looking at a re-route of the oil system.
Anything can be changed for the better unless there is no money or time or want to fix the issue correctly.

as you mention the sump needs to be relocated so then relocate the sump then make the PU suit the sump. Add a few gates and baffles to direct the oil to the PU and oil pressure issue solved.
Now the blow by issue from the top end needs more venting to the lower end. the oil is misted by the valve train and the drain back holes are not getting the oil to the sump without causing it to aerate along the way.

You must develop a way to drain the oil to the base that does no cause the lower base pressure of the rotating wiping the oil about the crank case assembly to stop it from returning from the head area.

Run a vacuum pump if you have to to get the internal pressures under control and use a puke can mounted externally to catch any misted oil and a drain back hose to the sump.

Some Suzukiès had this issue and the fix was larger drain back holes in the gasket to allow the oil to get back to the pan without the base pressure causing oil mist or blow by to get all over the engine externally

[Kevin Johnson]

WAG is that the opening is offset to help counter the natural development of a vortex to the surface of the oil. If you move the opening add some convex dimples to the smooth cover. There is a reason other OEMs did this.

The return pipe works simply by communicating volumes. Similar to the setup in the Porsche 944.

[AC sports]

WAG is that the opening is offset to help counter the natural development of a vortex to the surface of the oil. If you move the opening add some convex dimples to the smooth cover. There is a reason other OEMs did this.

The return pipe works simply by communicating volumes. Similar to the setup in the Porsche 944.

Interesting. I'll look at other oem solutions to this. It would definitely affect the vortex as you say.

[Kevin Johnson]

WAG is that the opening is offset to help counter the natural development of a vortex to the surface of the oil. If you move the opening add some convex dimples to the smooth cover. There is a reason other OEMs did this.

The return pipe works simply by communicating volumes. Similar to the setup in the Porsche 944.

Interesting. I'll look at other oem solutions to this. It would definitely affect the vortex as you say.

I think for a circular opening the indices of an equilateral triangle would work. You can see the type of convex bump/dimple that I mean.

[AC sports]

I always thought those dimples were to stop the pickup closing up totally in the event of a pressed steel oil pan being hit and pushed up against the opening.
I usually weld 2 or 3 nuts around the opening for safety.

[Kevin Johnson]

I always thought those dimples were to stop the pickup closing up totally in the event of a pressed steel oil pan being hit and pushed up against the opening.
I usually weld 2 or 3 nuts around the opening for safety.

Some time ago I found the technology listed in a patent. Naturally each OEM came up with a sufficiently different variant so as to avoid licensing fees.

Yes, there are firms that use tabs of one sort or another as a way to prevent closure of the gap due to a shunt or hitting debris, curbs, etc.