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Old 02-25-2019, 11:45 PM   #55
Scooby Newbie
Member#: 493470
Join Date: Nov 2018
2019 STI
Crystal White Pearl


Originally Posted by car_freak85 View Post
@xX_STI_Xx, does oil not also drain off cylinder walls in a vee or inline engine when it is shut off as well? That dog doesn't hunt...

I agree 100% on the oil drain-back not being as good, but the oil trapped in the cylinder walls doesn't care how the cylinder is oriented, the oil will still follow gravity and pool around the piston rings in a vee or inline engine, where in a flat engine the oil just pools at the lowest point in the cylinder bore.
Sure, the concept is the same across any piston-type combustion engine (V, I, or H layouts). However, like you mentioned, the oil drains back down with gravity between piston skirt & cylinder wall MUCH better in a (V) or (I) type engine than a Boxer (H) motor. Why? Consider the expansion and contraction of the piston rings when they are hot vs. cold. Piston rings are gaped to allow for expansion when the motor is up to temp right? when the engine cools down, the rings contract and the gaps or ring openings are more pronounced or apparent...thus allowing oil to continue to drain back down the cylinder walls via gravity. This does not happen on the Boxer motor. The oil settles at the lowest point of the cylinder wall and remains there until the motor is run again.

Again, nothing serious as Porsche's are designed the same way. Just like Porsche's, we just need to check our fluid levels more often that's all.
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