Metal fatigue in Lycoming engines limiting its TBO?

On 3 Nov 2004 10:25:09 -0800, (Wolfgang) wrote:

Many of the small Lyc. engines have a TBO of around 2,000 hours. My
O-320-D3G (TBO 2,000hrs) has now 2,200 hrs since new, it's never been
opened for any reason. Of the above time, 1,100 hrs have been flown in
my RV-6.

I change oil (15W50) and full-flow filter every 50 hrs, cut-open the
filter for inspection, and have the oil analyzed. The compression is
still in the mid-70s.

I plan to continue flying until any of oil analysis/compression/oil
consumption would indicate a noticeable departure from their historic
values.

I am flying the same engine (O-320-D3G) with 2500 hours on it, a Lycoming
factory reman in a Warrior. I do all the things you do. Compression was
consistently in the mid 70s. This year's annual showed a drop in compression on
one cylinder. It was noticeable, but not unairworthy, so we are still flying
it. We are checking the compression often and planning a engine replacement for
this winter.

Catastrophic failure is a concern for all engines, new and old. Fly the thing
until it tells you it is tired. Test the compression often. If you can do it
yourself, do it every oil change when you rotate the sparkplugs - you are
rotating your plugs, yes?. The differential gauge is less than $100 and if you
already have a compressor it's your only expense. Google for information on how
to test compression or contact me and I can point you to what I have found.

Demonick