Hi Jim
It's not "slightly loose flywheels", but quoting Butch (aka 38AC) a Guru of stactionary engines, in reply #180 (
https://listerengine.com/smf/index.php?topic=8320.msg100707#msg100707), it says, and I agree, was only slight corrosion.
I think that a loose fly will unbalance the engine, in the way you will notice emediatly.
Sizes where ok and I refit flys perfectly.
Be carfull of "a well tightned gib key" because gib is made of very soft steel, in fact gib are a mechanical fuse in order to shear if something suddnely get stuck (normaly pulley), and must be tapped with the right force - about this issue read Peter Forbes (aka Listerdiesel in LEF):
http://www.oldengine.org/members/diesel/Articles/rrchapt6.htmA few days ago (befor finish the 12/2) I read (I think was Utterpower) about best way to fit flys, and I did like this:
1 - A good clean of shaft.
2 - put some baby powder (yes, baby powder) in the shaft and push flys along.
3 - I left 1/4" (in fact 5mm) as 38AC advized, between outside face of the bearing housing and face of fly (put a 5mm steel rod in gap).
4 - snug gib key, and after a good tap in a long rod of brass with a mallet, to not damage gib.
I think Listers don't need any stuff like loctite - Lister are pure mechanic.
Cheers
VP