The Thermal Time Switch is a pipe thread which is pretty much universal.
And the late B20 Block that I have worked with is only metric on the bellhousing
mounting bolts and the maincap bolts, both of which are M12-1.75. All the other
threads on the block are Unified, not Imperial, just like the earlier B20s and
B18s, not to mention the B30s. Some of the sensor holes, particularly the temp
sensors seem to be UNF (formerly known as SAE) threads.
In any case I have them from both B20 and B21 so it will be easy enough to check
them out, which I plan to do in the morning. They sure look alike.
--
George Downs, Bartlesville, Heart of the USA!