Re: Johnson K45 piston/cylinder

[George Emmanuel]

PM T2,

You can’t use buttons on that engine….exhaust ports are on the bottom..

Regarding cotter pins, I have seen too small of a pin used because the holes in the wrist pin and the piston bosses don’t line up perfectly and prevent the correct size from going all the way through, so folks use a smaller pin. I encountered this on a motor recently. So before installation in the motor I put the wrist pin in, aligned the top hole perfectly with the wrist pin hole and then used the correct size aircraft drill and drilled through. Using too small of a cotter pin allows the wrist pin to rock and eventually the cotter pin breaks….ugghh.