Quote Originally Posted by vnx205 View Post
About the time I was in Primary School (the middle of last century) there was a fairly widely held belief, especially amongst school boys who thought they knew everything there was to know about everything, that using some oil was a good sign.
I think the theory was that a bit of oil had to make it past the oil rings to make sure the compression rings didn't wear out.
Does anyone know whether that was actually true at the time with the existing technology or was that just some sort of schoolboy mythology? Or was it a rumour spread by manufacturers who didn't know at the time how to reduce oil consumption?
As Bigjon says, there has to be some oil get past the oil control rings to lubricate the compression rings. Applies just as much now as it did then. The difference is that with pressure from emission regulations, plus more careful design and more accurate manufacture (so there is just the right amount of ring pressure on the cylinder wall), the amount of oil needed is very small.

But some manufacturers used it either as an excuse for poor manufacturing and design, or they actually believed that a lot more was needed than turned out to be the case when the pressure came on to reduce emissions.

John