Bill,
Plug wire loose is (very) secondary to the push rod. I almost missed
this message, because you didn't convey the HORROR of the racket made by
the push rod slamming into the valve cover. Perhaps because you were
motoring along relatively calm.
Yes, I've had this happen several times. One of two (2) possibilities,
one of which you discussed. Secondly, you may have unknowingly raised
your temp (or whatever) to the point you had a valve partially stick (or
possibly just floated it, as you gave mention earlier). This happened
most recently to me about, oh, maybe a year and a half ago. I ALMOST
missed this, due to being 'camoflauged' by the spring (eye 'passing' over
it), but the top of the guide had broken... literally looked like it
shattered... (I've since suspected shoddy manufacturing). Anyway, I
can't stress enough how much I almost missed it. Don't know if it broke
before, during, or after, but it wasn't good. (at 75mph on the
interstate, and pulling harder, its AMAZING the 'din' the rod makes
getting repeatedly slammed into the valve cover by the camshaft
lobe/tappets).
Please check your guide. Also, you may want to, as a matter of course,
pull the head and 'spec' your valves, paying close attention to the
afflicted one, 'specially around the head. While the head is off, you
may want to check the piston, see if there's any minute 'impact'
indentations in the deposit atop the piston... see if anything was
literally bouncing around in there. Crazy as it sounds, if a bit of
minute foreign matter cased your valve to stick just for a second, might
be because of worn valve stem (i.e. to much play in the valve/guide
specs).
FWIW, I had some serious wear of the valve stem... probably due to the
broken guide (but of course, there was no rocker action on the afflicted
valve stem once the rod slipped it's cup, so perhaps it happenned well
earlier... don't know, just be careful). After replacing and lapping
that valve, I fired her up none the worse for wear.
Don't forget to torque again after running her for a while (I think the
book calls for a re-torque at 500 miles).
MOST IMPORTANT OF ALL, is to remember that I am NOT a mechanic, so listen
to those more in the know for good ideas. There's some awesome
talent/experience on this list.
LWB,
Gary J. Durham
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