"Frode Berg" wrote in message
...

I have one more question regarding a factory overhauled engine.
Is it critical in any way to fly the first 25-50 hours quickly?
Can we shorten the life of the engine by letting the plane sit in the
hangar
for many days/weeks between flights?

Mineral oil used for break-in has no additives to help
it stick to moving parts when the engine isn't running.
Also, before the cylinder rings seat, you'll get a lot more
blow-by into the oil which will make it dirtier quicker,
and subsequently acidic and corrosive. You want to minimize
the time you have that crud in your engine. So don't
let it sit for long periods & fly at least every day if you
can. At least for the first few hours.

FWIW, I flew the first 8 hours of my break-in in just
over a week & then drained and refilled with fresh
mineral oil. I didn't reach the 25 hour mark until about
3 months later. The first 8 hours were flown at close
to full throttle, and as far as possible below 4000' to
keep the MP up high. I replaced at 8 hours because
my after-market filter got clogged up with gunk so that
the bypass light came on & the oil was absolutely filthy.
Runs great now after 120 hours, oil consumption minimal.