Tight engine UPDATE

[700rpm]

See post #24 on page 2 for most recent update.

OK, I thought it was a ring gap problem, but now I don't think so, but I am lost for options. Here is the earlier thread for background:
https://fordbarn.com/forum/showthread...=170253&page=2

I set the rings all to mfg's specs, and rechecked the clearances of the pistons and rod bearings. I changed out the starter for one I knew was strong, and the battery is only six months old and has a full charge. I finished reassembly yesterday and went for a ten mile drive today. When I stopped, the engine would not turn over. I waited about four minutes, then it would turn very reluctantly, enough to get started and head home.

When I got home I shut it down, and immediately tried to start it. It would not turn over. I tried by hand, and I could turn it partially, about 1/4 turn, with the crank, then no more, but I’m a weak old guy. Then I removed one spark plug, #2, just to see what that would do. It turned over with the starter!

At no point on the drive did the engine indicate overheating according to the motometer. The radiator doesn’t feel overly heated in comparison to my other A’s. Perhaps removing the plug relieved the compression, allowing it to turn? This might also happen (release of compression) by waiting five or ten minutes.

I am pretty sure at this point it is not something that is too tight, but perhaps something that just needs more breaking in. That may be wishful thinking, but I’m gonna go with it, and drive it, unless someone comes up with a theory about what the hay is going on here.