From: Nina Barton <ninab@scoresheet.com>
>Hi Everyone,
> I have a 1971 MGBGT, but am rebuilding an earlier engine to put in
>it. The pistons are almost brand new, and have no signs of wear or scoring
>on them. Would it be advisable to replace the piston rings, even if the
>ones I have look perfect? Since much of the rest of the engine has been
>redone, I'd hate to skimp and have potential problems down the road. Any
>advice? Thanks, Nina
Well, Nina, it's up to you. If you did a compression check on the motor
prior to the tear down and compression is okay, it's still be okay when
you're done. So you might do nothing. Without a compression check, you must
rely just on the visual. If they're truly shiny new looking, then new rings
may not be justified. Any hint on the number of miles on the motor?
You have to be careful if you replace the piston rings as the old rings may
have formed a groove at the very top of the cylinder wall. New rings are not
likely to match with the groove and will break on contact. There are tools
that remove the groove (ridge reamers) but, if not done expertly, can leave
a slight notch on the cylinder wall and the new rings may take forever to
seat.
There are plenty of "Grapes of Wrath" engine rebuilds, though, where the
engine ran find for years afterward without replace the rings.
The "right way" is the first overbore, new pistons, and new rings. Of
course, asking a mechanic on what to do is akin to asking a barber if you
need a haircut.
--
Bob Allen, Kansas City, '69CGT, '75TR6
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