Douglas S6 ring gap

[alan reid]

Douglas S6 Piston Ring Gap.
I am putting together a 1930 S6 engine and looking through the Douglas Care & maintenance book
it states the ring gap is .004 in!
My question is, is this enough.
Alan Reid

[cardan]

Hi Alan,
Radco says "at least .003" per inch of bore" for a "standard engine"; I wouldn't go below this unless the packaging for the rings expressly says so.
Leon

[richard s1]

Make sure your pistons are the original cast iron ones.  Hepolite and Specialoid made aluminium pistons for retro fitting and they don't fit very well in S/T6 barrels when hot.