Having had the much improved refurb of the engine it looks like we have too much oil getting into the rocker boxes … it’s good to have them lubed …but not over lubed
The pipes from the sump route oil up to the rocker boxes and it then drains back down the alloy pushrod tubes …
If the feed is too great then 5e exit back down into the sump can’t keep up … so the rockers fill and, eventually, it reaches the old vent drilled hole that allows venting to the head fins
To confirm all this I’ve now got use of a converted rocker box head … that has had the centre cut out and a glass inspection panel sealed in place. This will allow us to run up to speed and eyeball exactly what is happening
If we find the oil supply is too great … then it’s probably a simple switchover of the oil feed pipes … it seems the ones in place now are high capacity feed
Update .. late September … looks like it might have been user error. I replaced the oil cooler matrix with a new slightly larger one … and, on refilling with oil, I was over generous allowing for the new EMPTY matrix … by about 750ml ! This had nowhere to go .. except out through the breathers …lesson learned 😊
Jersey Sherwood Ranger 
Hi,
it’s Marco here from Italy, i’m running a Fly Synthesis Storch powered by a Jab 2200A Gen1 (solid lifters). I’m experiencing severe oil fouling of spark plugs on cyl #4 in about 3 Hours of flight, the “lighter experience” is about a mag test fail on 1 mag, while the “havier” has been a complete cylinder fail (off) in flight, luckly the airplane is quite light and can flight safely home with only 3 cylinders running..
The problem seems to be very related to low RPM settings like idling on runaway, or idling for landing/descending.
I’m writing you because this post is describing exactly my suspects, too much oil in the rocker chamber, leaking down somehow from valves to the combustion chamber, but you wrote it was “user error” and because of that error the oil had “no other way to go”.. here we are to the reason of this message: i need to understand this better, because of my english understanding level i am not capable to understand what your error was about exactly, can you please try to explain me your “error” in different wording so i can learn from it?
I also run an extra oil-cooling-radiator (is this what you mean when you say “Matrix”?) and I also have been doing some “user-errors” while adding oil: just after overhaul i ran about 10 hours with too much oil (if we consider the lower mark on the oil stick as 0% and the upper mark as 100%, i was running at 125-130%).
Thank you so much, Marco.
Hi Marco
Good to meet you (albeit remotely!)
You do sound like you have had a lot of problems and it’s quite difficult to know where to start as you have had so many problems !
If the post you are referring to was about my Jabiru overheating in the early days it was because I put a very small oil radiator on … and this needed to be 3 times bigger !
I had problems post an upgrade to the engine and this we eventually found was due to the small rubber rings that go in the end of the rocker shaft tubes… this was allowing oil to seep from the rocker head down the outside of the shaft guides
Kr
David
How are you getting on Marco .. you can email me on dsbreflex@gmail.com