Piston ring gap

[rafa89]

Hi,

Looking for some help again!

I'm rebuilding my AAN and installing Wossner 81.50mm piston.

The machine shop set the piston to wall clearence of 0.07mm, as stated on the box.

My question is abouy ring gap, as I didnt find any definitive anwser after some search. Out of the box they are:
1st: 0.30mm
2nd: 0.35mm
Oil: 0.40mm

I'm running 1.8bar. Do you think those gaps are suficient?

Regards

[SteveH]

The standard gap for the OE rings is 0.15mm to 0.35mm with a wear limit of 1.0mm. I don't know what material Wossner use for their rings, so there's might differ based on the thermal expansion of the material they use. I recently put new rings on my pistons with a new block, so standard bore. The rings came gapped at 0.3mm, so I left them as they were. Higher power motors will require larger gaps to accommodate the additional heat/cylinder pressures generated. I'm sure someone on here will have a high output motor using Wossner pistons who can advise what they have used.

[rafa89]

Thanks for your input!

Following wossner generic table and assuming turbocharged factor, 1st ring should have a gap of 0.45mm, 0.53mm for the 2nd and oil control ring between 0.35mm to 1.00mm.

I'm waiting for wossner reply, but withou any other experiences reports, I think I'm gona follow the numbers above.

Do you guys think its safe enought?

[Error404]

For road use with moderate boost up to around 2bar I set them at:

Top 0.45
2nd 0.50
Oil 0.35+

[rafa89]

Perfect, that's the intended use!

I will set then with those numbers.

Thanks a lot for your help!