[Healeys] Ken's three pistons final

[Freese, Ken]

 The two Mikes are in agreement. Michael Miendorfer and I stripped down
my engine yesterday and his analysis pretty much equals Michael Salter's
on the cause of my holed pistons. See M. Salter's comments below from 6
months ago. The ring movement was happening in all pistons so eventually
my thee piston problem would have been 6. Luckily there is no real
scoring, just normal cylinder wear, but I doubt we can get by with less
than a .010 overbore.
 One thing, I should mention that when I rebuilt the engine in 1983, I
did not replace the timing chain damper. Yesterday we found the rubber
rubbing block had separated from the steel backing plate and was
floating loose within the timing chain cover. The chain had worn itself
into the steel backing plate and made big grooves. I don't remember
noticing a timing fluctuation, but then with electronic ignition, timing
check/tuneups are not performed as frequently as the old days.
Ken Freese
65 BJ8
 "I am pretty sure that ring failure was the root cause of this problem.
I would hazard a guess that either the rings were not gapped adequately
or the engine has been overheated to the point of partial seizure at
some stage. Take a close look at the cylinder walls there may be some
signs of scoring as a result.

I think that when a ring seizes the ends tend to dig into the cylinder
walls and jam. That causes the sort of damage evident in picture #5 & #6
with the straight end at one end of the damage area and a tapered area
of damage at the other.

I'm pretty sure that the depression in the middle of #6 piston and the
ridges on #3 are the result of pieces of broken ring. In the case of #6
piston these will have migrated from one of the other pistons, probably
#4 with which shares an intake plenum.

The fact that the #3 piston has the little ridges on it is a pretty good
indication that the extremely high temperatures associated with
detonation have not occurred. "- M. Salter