The engine manufacturers that we use do not recommend ground run on the engines just because we can.
If you want to run it on the ground just because you can, please go look at the manufacturers recommendations and show me where it says to run it on the ground other than for checkout before 1st flight after a rebuild.
We have already had one person that has been working on these engines for 40-years say not to run it. Please look for someone with 40-years or more experience say you can. 40 people with one year experience with these engines is not the same as one with 40-years of experience.
Lycoming Tech Tips can be download
here.
One can find Lycoming recommendations in the Tech Tips document. Do a search for ground and read.
See page 62.
From page 62 follows:
Some operators are running the engines on the ground in an
attempt to prevent rust between infrequent
flights. This may harm
rather than help the engine if the oil temperature is not brought up to
approximately 165˚ F, because water and acids from combustion will
accumulate
in the engine oil. The one best way to get oil temperature
to 165˚ F is to fly the aircraft. During flight, the oil normally gets hot
enough to vaporize the water and most acids and eliminate them from
the oil. If the engine is merely ground run, the water accumulated in
the oil will gradually turn to acid, which is also undesirable. Prolonged
ground running in an attempt to bring oil temperature up is not
recommended because of inadequate cooling that may result in hot
spots in the cylinders, baked and deteriorated ignition harness and
brittle oil seals which cause oil leaks. Pulling on engine through by
hand if it has not been run for a week or more is NOT recommended,
and can result in increased wear. Refer to Lycoming Service Letter
L180.
Just my opinion.