At 12:01 PM 5/29/2011, Rocket J Squirrel wrote:
>(1981.9L) Got the tin off the bottom of the left head. Three 13mm and
>one 12mm? Who designs such things?

Sounds like someone put a Japanese bolt in there.  J.I.S. bolts have
a 12mm head where M-series have 13.

>The switch reads open to frame with the engine off, so it's a goner.
>Found the fossilized remains of what appears to be an ancient
>Pre-Columbian rubber boot on the switch. After than crumbled off, the
>the brass push-on connectors had nice green verdigris.

Because of the sliding action the terminal is self-cleaning to a
considerable degree.  This is a signal connection so contact
resistance may not be so critical.

>When I pull the switch, will there be much engine oil loss?

Depends how quick you are putting the new one back.  Generally
speaking I'd say not much, especially if the engine is cold.  But if
you have to go back to the house to get the sender you might lose
some.  It would be limited to what's in the galleries though, I'm
quite sure the oil pump would drastically inhibit siphoning from the sump.

Yrs,
d