Ring gaps

[itiejim]

I'm just checking the ring gaps as I reassemble my AJP V8 (TVR) engine. The build manual suggests that the top ring should have a gap of between 15-17 thou and the second ring should be 9-11 thou.

Measuring the (new AE) rings in the checked bores the top rings are all around 17 thou - OK, however, the second rings are all around 14-15 thou.

Having done a bit of research on this it appears that there is a suggestion that the second ring gap should be bigger than the top ring to prevent piston ring fluttering. I have also come across a "calculator" which suggests that piston ring gap should be calculated as bore (inches) X 0.0045 (top ring) or 0.0055 (second ring). This would give me gaps of 16 and 19 thou respectively.

So - what should I do - leave them as they are, try to get another set of second rings to achieve the TVR guidance or open them up as per the "formula" above?

Any thoughts welcomed!

Also posted on the Cerbera forum.

Edited by itiejim on Sunday 24th January 11:49

[itiejim]

Thanks folks, what about the general theory that the second ring should have a greater clearance than the first?

I'll try to have a chat with AE on Monday too.

[itiejim]

TVR spec 15-17 thou top ring and 9-11 thou for the second ring.

I'll have 17 top and 14 second.

I was a little concerned that 9 thou was very tight anyway. So... fit as is?

[itiejim]

Excellent thanks!