TR3 versus TR4 piston ring end gap

["Jack I. Brooks" <brooks@belcotech.com>]

I've noticed that the piston ring end gaps are very different between the
TR3 and the TR4 as follows:

TR3     0.003-0.010 (83mm pistons) Bently Manual
TR4     0.010-0.030 (86mm pistons) Bently Manual

Does anyone know the reason why these two nearly identical engines should
have such different ring end gaps?

Thanks.

Jack