Z1OwnersClub GB

Finally getting round to fitting the 1075 kit that has been siiting on my desk for the last 6 months and straight away I am right out of my comfort zone

In the instructions with the kit it says to check for proper ring end gap by putting the piston rings in to the bore, squaring them up and measuring with a feeler guage.

If I have done my calculations correct the top ring should have a gap of 0.014 inch and the second ring a gap of 0.015 inch.

I have put the first top ring in , squared it up and measured the gap at 0.010 inch.

So what do I use for filing 0.004inch off a piston ring?


I was expecting to just fit them. Was not expecting to do this at all.

Further to the above I have just measured the second ring gap at 0.020 inch so that is to big by my reckoning????

What do I do about this???

A small file is what I use, but make sure the ring is supported or you may snap it.

I used a fine needle file.... which I clamped in a vice and held the ring and moved it gently back & forth on the file....
This method gives better control/feel to avoid damaging the rings
Be sure that you don't leave any burrs that could scratch the bore

Hi Rich,
Supported with what, pliers or mole grips?
and what do I do with the second ring that is to big a gap, having now rechecked it in every bore its actually 0.020 inch.

or a lolly pop stick. If the ring is too small check the other rings with it as well and if it is the odd one out send it back, if they are all the same maybe the problem lies with the bore being the wrong size.

Rich, a lolly pop stick, how?

Have checked all the bores with all the rings and they are all the same, is it going to be a big problem having a 0.020 inch gap on the second ring?

Just put it behind the ring you are filing and file the ring and the stick, It is only there to support the ring.

Hi Rich, understand now.

Does anyone know if 20 thou is going to be ok on the second rings?

Spoke to the engineering firm this morning they say its bored to the piston skirt. The problem is with the ring manufacter and that there is no problem running 20 thou on the second ring they have seen twice that anf its fine.

Dont know what to think?

Hello Steve R, the 2nd ring should always have a larger ring end gap than the first, the 1075 kit has a 2.835" bore, so you would want to aim for a ring end gap of 0.013" on the top ring and 0.016" on the second ring, if the gaps are larger than this do not worry, but be sure the gaps are not smaller than this, Regards, Steve

Thank you very much Steve. I will file the top rings to 13 thou and leave the bottoms at 20thou.

Thanks again I appreciate your advice.