[Terry Burtz, Calif]

Taildrager,

Thanks for your comments.

With your "screen" name, are you planning to use the "New Engine" in an airplane?

Since this is the 3rd engine that you have worked on, do you have someone that can help you? Your helper should be familiar with '60s and newer engines.

Regarding the flat head screws to hold the thrust bearings, Syncro909 is correct, the ones from China had thick heads and they were replaced with thin head screws. I know that all engines distributed in the USA and Canada had thin head screws substituted and that our distributors in Australia and Europe knew of the problem before distribution.

Regarding your main bearing insert problem, the half-shells are not round before assembly and they should protrude above the parting line. Hand tightening main caps 1 and 5 is not enough pressure to force the insert half-shells to become circular and that is why the crankshaft was hard to turn. The half-shells become round and the equivalent of a press-fit when torqued to 55 lb-ft.

After getting off the phone, I'm happy that the main bearing bore and crankshaft journal diameters of the "New Engine" were within specification.

By removing material from the ends of the inserts with 400 grit sandpaper on the table of your saw, you have destroyed your inserts. When torqued to 55 lb-ft, there is not enough material on the end of the insert to force it to become round and the equivalent of a press fit. The only thing keeping your inserts from spinning in the cylinder block are the bearing tabs. This is not good. A spun bearing will damage the cylinder block.

Fortunately, inserts with larger outside diameters are available, but to use these, the cylinder block bores need to be enlarged.

The connecting rods use the same insert, journal diameter, and housing diameter. I'm curious as to why there were no problems and happy that everything fits.

Terry Burtz