[ramuk]

I understand that these seals are around the crank (x1) and cam shaft (x2)

I just don't see how a rubber seal that's pressure fit can keep the oil from spilling out?

Is there active engine-oil on the other side of the seal?

I would appreciate some insights!

I am coming up on a timing belt change and have been reading up on the crank and cam seals and would like to understand it better.

 

[FLfrstr]

Seriously you don't see it, it fits perfectly or pretty darn close around the shaft and rides on a thin coat of lubricant usually grease and is like a splash guard for any oil that may find its way to that region. It isn't like oil is pooling there, the seals are well above the oil level in the engine they are really just stopping any incidental leakage. If they were below the oil level line of the engine they would most likely develop leaks very easily.

In as straight forward of an explanation as I can think of right now is that there is no oil behind those seals to "spill". They are just making sure that the oil doesn't leave the engine on its way back to the oil pan.

 

[flstffxe]

It may take a couple of times reading it to get it.
Anatomy of a Shaft Seal

How a Shaft Seal Works

Many shaft seals are under a positive pressure. Hydraulic cylinders can see 5,000psi or more. It is all about the seal design and how the pressure is applied to it. Most seals that are under a positive pressure are designed to use that pressure to aid in creating a seal.