TheMiniMan wrote:
There is another way to combat the problem without taking the cyl head off etc, & that is to simply make 2 decent sized drain pipes , externally from each end of the rocker cover back to the both the primary case breather & the fuel pump hole in the block. both these places are perfect for both crank case breathing pipes & oil drain return pipes
I fit this system on all our race engines & large road/rally engines regardless of whether the cyl head gets too much oil or not.
Yep, this is what I have set up too, on a slightly smaller scale; any oil getting to the catch can is drained back into the sump via the fuel pump hole.
However what I find is happening (probably due to excessive blow-by at high revs) is that the rocker cover fills up and oil starts weeping from around the oil filler cap (non vented type). I don't think this is an ideal situation and would prefer to reduce the amount of oil getting up there in the first place.
Is there "blow-by" normally generated from the valve guides? This may be the cause of the over presure I'm experiencing in the rocker cover. If the supply of oil is too great for the normal head-to-sump drainage path then this path is effectively blocked and any additional blow-by pressure in the rocker cover will result in oil being forced out the easiest path (the breather pipe).
Dave