Hugh---Being able to still see the cross hatch marks in the piston bores
may have given the mechanic to conclude that it was recently re-ringed.
Not a safe thing to assume that the cylinder taper was OK. Bentley
doesn't say how much taper and ovality is acceptable, but at least one
book that I have on the subject gives the following data:
Cylinder taper-- max. .008
Out of round-- .Max. .005
This seems a bit much on pistons less than 3 inches in diam., given that
new, round rings must then expand and collapse each time the piston
changes direction.
Seems like this would be a good prescription for blowby and oil
consumption.
Rings that are + .010 (if you can get them) wouldn't work well on std.
pistons. The next size up would be .020 over pistons, and of course a
rebore. Custom pistons run around $1000/set, the last time I checked.
Dick T.
.020 over
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