In article , John
Roncallo wrote:

This is true but the tach doesn't know any more than RPM. The rest of
the story is all assumed. What I'm wondering is did we replace our clubs
perfectly good running engine last year at 2000 hr or was it more like
(2300RPM/2566RPM)* 2000hr = 1793 hr. My most recent flying and some of
the posts in this group are telling me we may have replaced it at 1793 hr.

It doesn't matter how many hours are on the engine, it's why you had to
replace it?
Was it making metal?
Were parts worn out of spec that they could not be replaced?
Many things affect TBO.
Some engines go significantly beyond TBO, some significantly less.
Operation and environment make a difference.