Another disturbing noise from Ruby

[Stuart Giles]

As a specialist unit, I’m sure they know what they are doing and setting them square in the bores with say a 5 thou gap (I can’t remember the optimum gap off hand) should be fine.

However, when I was a spotty teenager and thought I knew it all, I rebuilt an old Humber motor and didn’t gap the rings at all, but still got the pistons in and the result was a similar noise to what you have.

I hope I’m wrong!

My worry with no ring gap would be that they'd break when the motor gets hot, with the Humber motor it's good that you got a warning noise. 5 thou ring gap would probably be OK; but I've always used this chart, -which used to be packed along with replacement Hepolite piston ring sets- for gapping piston rings on any motor I've built.



So, .007" for an A7 motor