S52 standard size piston rings

[adamnur]

Hoping the track folks have some experience on this.

I'm rebuilding my S52, going to re-ring the pistons. Mine are stamped with 86.365, but these rings are ~150/cylinder from BMW. Grant are 300/set, total seal are 300/set.

If I go with the 86.415 rings also listed in realoem as standard, they're 40/cylinder from OEM suppliers and hastings has a set for approx $120.

Would the extra 0.05mm cause any issues? I'd rather not have to file anything. The cylinders look good, cross-hatching is all still there so would just need a hone to de-glaze not wanting to bore anything out either

Thanks in advance

[aeronaut]

You need to measure and adjust ring end-gaps no matter which rings you get.
The cylinders need measured for taper and roundness. (Having hatch marks means nothing.)
I'm pretty sure it's standard procedure to buy the 86.415's for ring replacement in a used cylinder.

[adamnur]

Thanks. I'm leaving the mic'ing to the machine shop, just want to have a replacement set of rings ready to go for them if the cylinders are good.