Quote:
Originally Posted by piersman
Hi HS, did you ever get an answer as to why your oil in the head wasn't draining back down to the sump with the car at rest? There was a discussion on one of your threads where the question was raised but the answer was never clear. I can understand that a small'ish amount of oil will always remain in the head but your engine seemed to have a lot in the effected side based on the pictures you posted. Shouldn't that have drained back to the sump (albeit slowly) once the engine was turned off?
I ask because I can see me taking the rear scavenge pump off this weekend and being covered in oil as it pours out the hole from behind the pump! 
Cheers |
Oil will not be returned to the sump without the aid of a scavenge pump. This is due to the design of the head and the fact that the engine is horizontally opposed. Oil can be drained back to the chain wells but will puddle there in some amounts if only sitting static.
Also, Scavenge pumps are high enough in the cylinder head that they can be removed with very little oil loss.
In my experience the smoke that is emitted from these engines when cornering IS NOT the fault of a scavenge pump. I see this condition routinely and have only had a scavenge pump replacement dove it in the instances where a scavenge pump has failed. These failures only occur when a pump sucks debris from another failed component into it, thus seizing the tightly internal clearance pump and breaking the drive tang off completely. This results in a mechanical disconnecting of the pump from its drive and also generally has other symptoms, like exhaust cam retardation on the afflicted bank that can be great enough to make valves contact pistons and bend them.
An example:
Timing chain failure shed a portion of chain roller. Scavenge pump inducted this, pump seized and drive tang snapped.
And here are the damaged pistons from valve timing retardation allowing exhaust valves to contact pistons:
There are lots of dynamics behind each of the 27 modes of failure I have documented, with primary and secondary failures along with collateral damages extending from each.
If I had to bet, you are not seeing a scavenge pump deficiency.