Propulsion.

Other than the flywheel assembly, this main case bolt was my only other problem.  I had let the gasket material set for a couple of minutes and then joined the cases. They went together very well.  I then quickly started all six case nuts.  Five started with no problem and I got those fully run on ready to tighten.  This one would not start. It was second in the torque order so I did the first bolt to its initial torque value and examined this nut more closely.

The nut threads were fine, but when I looked at the bolt thread, the first full thread was smashed over and there was no way the nut would start. The only way to start the nut was to file the first thread off, but with the engine opening I didn’t want any file dust to get inside.

I quickly covered all the push rod holes and cylinder holes with 2” wide blue painter’s masking tape.  I then filed off the thread and was able to start the nut. I cleaned the file debris and then removed the tape.   I ran the nut on and torqued it to its initial value. After the final torque values were applied to all the case nuts I checked the nut and as I suspected it would, the nut had run past the first thread and filing it off was of no concern.