From the time I was working on a engine of my motorbike I remember that
putting some oil into the cylinder was used to make a distinction
between worn out rings and worn out valves. Start with a (hand)warm
engine, so piston and cylinder are closer to working temperature,
measure compression, that some oil in the cylinder, and again measure
compression.
But that was an engine with vertical cylinders, I don't know if this
works with horizontal cylinders.
Also when an engine wasn't used for a long time, rings could "stick" in
the piston grooves, another reason to let it run for some time.

Jaap
'87 Caravelle diesel

Ken Lewis wrote:

>I would say it is more of a difference between dry vs. wet instead of cold
>vs. hot. As in the rings having oil on them or not.
>Ken Lewis
>http://neksiwel.20m.com/
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