Do we have an engine oiling problem with our BMW 435i?

What prevents the scavenge pump from losing its oil and just sending air when any 1 of its 4 pickups is no longer submerged and need it the most?

In reply to Driven5 :

That would be a real concern if there was one pump drawing from all the pickups, but typically the scavenge pump is actually a set of separate pumps (sometimes referred to as "scavenge stages"), with one pickup per pump, so if one sucks air the others can still suck oil.

The scavenge pump doesn't feed the main pump directly, it just feeds the well where the main pump picks up. 

In reply to GameboyRMH :

Yeah, they're calling it a 'twin flow gear pump'. So I'm guessing it's basically a '2-stage' pump, which would answer my question. It looks like they're also using the turbo drains to also (gravity) feed each side and give it more capacity to keep up during prolonged high-G cornering.

Maybe something like this is needed?

https://www.ecstuning.com/b-mmx-performance-parts/mmr-n55-baffled-sump-plate/mmr20-0501~mmr/

The n55 also added variable oil flow with a bypass solenoid at the front of the engine.  As the similar n54 did not have as many bearing issues I wonder if that contributes to problems as well.  The s55 oiling system should help

I'm interested in your solution since we've had similar problems with OEM oiling in endurance racing.  I'd be even more interested in BMW's excuse for not designing a solution for the pan which would have cost them zilch..  but has now damaged their reputation...  

Is this what was installed?

https://www.bimmerworld.com/S55-Oil-Pump-Upgrade-OEM-135i-M235i-335i-435i-N55.html $1649.99

Keith Tanner said:

Is this what was installed?

https://www.bimmerworld.com/S55-Oil-Pump-Upgrade-OEM-135i-M235i-335i-435i-N55.html $1649.99

It is indeed, along with the S55 baffled pan. We didn't replace the oil pump sprocket, though. Unless you're taking the front cover off (which adds cubic hours), the sprocket needs to stay in place to keep tension on the drive chain. I think BimmerWorld said this was like the third conversion they'd done and they've refined the package a bit each time. 

JG Pasterjak said:

The scavenge pump doesn't feed the main pump directly, it just feeds the well where the main pump picks up. 

So it's a kind of integrated dry sump.  Neat.

Pete. (l33t FS) said:

JG Pasterjak said:

The scavenge pump doesn't feed the main pump directly, it just feeds the well where the main pump picks up. 

So it's a kind of integrated dry sump.  Neat.

I'm going to call it a "moist sump" and good luck trying to stop me.

In reply to JG Pasterjak :

I'm fine with "moist sump",  just be glad there's plenty of girth to it to make sure it get copious amounts of oil to squirt.

russelljones48 said:

I'm interested in your solution since we've had similar problems with OEM oiling in endurance racing.  I'd be even more interested in BMW's excuse for not designing a solution for the pan which would have cost them zilch..  but has now damaged their reputation...  

Yes, BMW's Stirling reputation for reliability was sullied by the N55. 

calteg said:

russelljones48 said:

I'm interested in your solution since we've had similar problems with OEM oiling in endurance racing.  I'd be even more interested in BMW's excuse for not designing a solution for the pan which would have cost them zilch..  but has now damaged their reputation...  

Yes, BMW's Stirling reputation for reliability was sullied by the N55. 

I chuckle because it's true, but know that I do it with a single tear running down my cheek.