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May be worth tapping a couple of holes in the sump and end cover flanges so you can use a jacking screw to help get things apart, often seen on old steam engines
We are in danger of spoiling Doubletop's excellent Puma build with all this O ring piston ring discussion. .........................
Viton o-rings do an incredible job of sealing a piston in a cylinder. Based on experience, I use a single 1/16" nominal cross section o-ring in a 0.094" wide slot x 0.058" deep in the piston
Maybe we should adopt the social media habit of including #hashtags in our posts so a search for say #Orings or #OringvCI will bring up all the threads on the subject (a search will find this one now ). I'm sure there will be a number of discussions that would benefit from retrospective #hashtagging. The mods could add a sticky on the topic #Hashtags and maintain a list of those to use so everything gets correctly grouped.
That exhaust looks a lot cleaner now with the baffles in place
Great engine and build log!! What about a dyno run?
Doubletop--Look up "Prony brake". That is a method used to calculate engine horsepower. There are Youtube videos of it being applied to model engines. ---Brian