When I first cracked a cylinder head I looked up main causes for full size aircraft and it was something like the mixture was too lean and something about timing. (This was in 2016 I don’t fully remember) however since I had the engine apart I was looking at the relationship of the master rod and sister rods and the hole in the hole in the prop hub that has the pin to keep it in place. On No.1 the hole lines up with the hole in the cam cover and the piston is at the top of its stroke. However on 2 and 3 it has a little before and a little after. This confused me so after further investigation I thought the master rod was designed wrong. So with some time spent in AutoDesk Inventor and the use of a friends 3D printer I was able to make ( what I thought) a corrected master rod. See pics. I installed the part and yes it did correct the timing of the piston to be at top of stroke and the hole lined up with cam cover. But I brought the pistons to far down and would hit the crank and not allow it to rotate fully. That was as far as I went with the idea. I’ve included a pick of the master rod and you can see how I relocated the sister rod holes. Soon after I figured out that the timing of the magnets was not right but didn’t know how to fix it.