LCGB Forums

What is the max ring gap for tuned motors ? Stickys manual says 0.6 for standard but MB suggest larger 0.5 which isnt larger.

Both will run ok but I've just stripped a top end and measured the ring gap at 0.55 and there is quite a bit of colour beyond the rings.

Doesn't the gap vary according to the bore size? I seem to remember being told the gap was a percentage of the bore diameter

I read that too coaster but it made my brain hurt lol.will check that,my gap is 0.64 on 70mm bore.

The ‘rule of thumb’ for minimum ring gap that I have always personally used is ‘a thou per circumferential inch’ which, for Ø66 mm bore equates to just over eight thou (0.0082” or 0.21mm)

However, these days, it’s not often that you will acquire rings as ‘tight’ as that.

So, possibly advice from a manufacturer would be worth considering.

Wiseco say four thou per inch of diameter which, for Ø66 mm bore equates to just over ten thou (0.0104” or 0.26mm)

I consider the maximum ring gap to be a grey area.

From what I now recently understand, a brand new ring with a larger gap would be better than an old, worn ring from a bigger bore that had been ‘gapped’ to suit a smaller bore.

There has been some research on it & the actual ring gap is not as critical as the radial function of the ring in its groove.

Hopefully, that makes sense & I am not advocating huge ring end gaps.

I looked at the wiseco site warkton and got the same measuremant. Theres no sign of anything getting passed the rings,its just ive had to deglaze the bore on a steel lined TS1 and know how easy it is to get carried away.I have some new rings on the way and when they eventually get here I'll compare the measurements.