If you recall, I installed an Anti-Splat oil-air seperator that features an exhaust line connection to a vacuum valve mounted to the exhaust pipe. The concept: Vented oil is vented into the exhaust pipe, which also creates a mild vacuum in the engine case to boost horsepower.
I have decided to remove the vacuum valve in light of several reports of coking at the valve's mouth into the exhaust. One pilot/owner's RV-8 engine suffered a catastrophically blown engine seals and engine failure...they made a successful dead-stick landing.
Given what I now know about the risk, I chose to manage that risk by eliminating it completely.
