G.R. Patterson III wrote:

text news wrote:

snip

I understand that with "re-built" you get a new log book. This sounds good
but in practice it is because the engine has been re-built from a collection
of untraceable parts, hence the new log book, so the advantage seems
emotional rather than mechanical!


You've been lied to. When Lycoming creates a remanufactured engine, they use mainly
new parts. Whether new or used, all parts used meet the spcifications for new parts.
That's the logic behind the new logbook.

If "mainly" means pistons and cylinders, yes. So by parts-count, I guess you
could say "mainly". But AFAIK you are taking pot luck on some pretty expensive
parts: crank, cam, case.


When Lycoming overhauls an engine, they also use used parts "from a collection of
untraceable parts", but those parts only have to meet the specifications for return
to service. Either way, they install new pistons and cylinders.

New pistons and cylinders, yes. Since the prices of new pistons and cylinders
from Lyc have dropped so drastically a few years ago, I don't think anyone is
overhauling Lyc cylinders any more. The cost of overhaul is too close to the new
price.

snip


The main thing that gives problems is the cylinders. In a field overhaul, your
old cylinders are usually bored and re-used. If necessary, the bore may be
plated back up to size. Other things may be done to recondition them, but, any
way you look at it, they've put up with a lot of abuse. Few cylinders will reach
TBO three times; some won't make it twice. Lycoming replaces the cylinders with
new.

I think this is obsolete information. It was true a few years ago, but these
days field-overahulers are putting in all-new cylinders.

snip

Dave
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