In the initial start up of Sentinel it would just hit a few times and stall. After playing around with the cam and ignition timing a few degrees and no difference, I felt the compression was too high. The power stroke wasn't enough to overcome the compression for the next cycle. I removed the 3 washers in the conrod beam and the engine responded a few more beats. After shortening the beam 3/32nds and reinstall, the engine ran and it was just a matter of setting fuel mix for a steady idle. Here checking the height, piston to top of cylinder to get numbers for a volume check. No need to check cylinder head volume separately as the cylinder itself is the combustion chamber here ( it bottoms to internal roof of head) and plugging the numbers into a static compression ratio calculator indicates a 3.3 compression ratio. The black O-ring around cyl. is the head gasket.
. can you tell me what takes the thrust from the cams, I don't see any tappets, does your engine rely on the generous sized guides you have used?
