Also to add to that, I feel I can say that the PCV was a very signifigant part of any oil being burned by this engine.
Over the years we had a stroker engine where a catch can was the solution to a similar issue. And currently we have
another one (that gets wound to ∞ ) where I'm going to refresh the rings -and- put a catch can on it also.
One possible reason I think why catch cans are becoming more popular has something to do with us increasing
the piston displacement while at the same time being forced to do this in the
same total internal volume defined by
the block. Back in the '50s there was a 265 or 283 worth of piston displacement stirring up the internal volume.
(And a no-resistance road draft tube to relieve any pressure from imperfect piston ring seal.)
Fast forward to today, and we're grinding the inside of the block in order to make room for a stroker 383.
Or running a .030" over 406. And yet we're doing so in the
same internal case volume as the old 265/283 motors.
Now some will jump in and state that the 'average' displacement inside the engine remains the same (one piston
going up while another is going down) but since the air is still being pushed around by the bottom of each piston,
there's going to be a lot more 'slinky-style air movement' between cylinders that are 180° apart from each other
in terms of crankshaft rotation. With enough added 'excitement' inside the engine, there's no doubt that there's
more oil vapor in the air, so as the blowby from the piston rings is evacuated via the PCV valve, there's going
to be more tiny oil droplets leaving via this path. Ergo the need for a catch can.
Note: A side effect of our added displacement is that there will be more vacuum on the intake side of the PCV valve
for a given vehicle at a given cruising speed. Even assuming the same state of tune, a 283 pushing a van down a
TX interstate at 80 mph is going to have a lower intake manifold vacuum than a 383, given the same gearing & all that.
So, more intense pressure pulsing on the same size crankcase on one side of the PCV valve, while at the same time
more
intake manifold vacuum on the other side of the same valve? Sounds like a recipe to need to add an oil/air separator
in line?
Given all of the above, adding a catch can to the mix makes sense once you think about it. Sure, the first thing that
comes to mind is to double-check the piston ring seal. But if you are already getting stellar leakdown rates, then we have to
stop & give some thought to what we're asking of this architecture. We're a long way from a 283, Toto. :0)