I have been running an open crankcase breather with a catch can. It works good in terms of performance, but probably isn’t doing our atmosphere any favors. I can do better. It was time to see if I could recirculate the crankcase vapors into my induction system without sacrificing any performance or economy.
I also wanted to revisit the Hayden KrankVent to see if I could improve performance. Maybe I could get a little better fuel economy, or crisper throttle response. The KrankVent is a one-way check valve that is installed in the breather hose. It lets air pass out of the crankcase when the piston moves down, but prevents air from being returned to the crankcase when the piston moves up. With the check valve installed in the breather system, a vacuum should develop in the crankcase. The vacuum will increase the differential pressure across the piston rings, and should result in improved power and efficiency. Seems like a good idea to me.
Back in March of 2020 I tested the KrankVent . Other than adding weight, the KrankVent didn’t seem to do much. I felt that the concept was technically sound, so I wanted to give it another try. When I did the initial installation and tests, I was using a compound gage graduated in inches of mercury on the vacuum scale, and pounds per square inch on the pressure scale. I always felt that the instrument I used was not sensitive enough to provide a clear picture of how the engine was behaving. The pressure I was trying to measure was extremely low (about 1 to 1.5 inches Hg). I really needed to be using a water manometer. One inch of mercury is equivalent to 13.6 inches of water. The resolution on a water manometer would be a vast improvement.
This is a link to the old KrankVent post. It provides some background info if you are interested.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1585377641