you said the oil or blow by is coming from your breather
cap not your pcv valve,if you pull your breather cap off
and look down the valve cover you will probably see
your rocker arms,if you do there are no shields under
the valva cover where you placed the breather cap
if this is the case plug that hole and look down another
hole on the valve cover and find one with the shields,
then put your breather cap there,the shields prevent
the oil from splashing up into the breather cap and
running onto the valve cover,also do this for pcv valve.
I had the same problem once.