I'm doing something weird, finally got my engine running correctly only for a slight lean condition in the basemap to crack a ringland on one of my cylinders. My question is, are there any aftermarket file fit piston rings available for an F23 that comes with a gapping instructions? If not, does anyone have a general rule? I'm only pushing about 8-9psi with a 54 trim turbo on a stock engine, but since I'm rebuilding it, I'd like to gap the rings.

 

If you don't get it tuned no amount of ring gap will save it. No professional tune = no boost, period, as you already learned.

Gapping rings is pretty standard. You can do it by hand with a vice and a file if you're careful, or you can buy a piston ring file. Just pick up a set of standard rings and add a few thousandths to whatever gap they recommend to account for the heat from boost. If the new rings don't specify a gap(they should), you can find that information via google or the factory service manual. Be sure to clock them correctly also. Make sure you inspect all of your other pistons carefully for damage.

My $.02 - Given my extensive history with the F series SOHC platform and boost, they generally don't need extra ring gap in stock form. With a good tune you will window the block before you crack a ringland. H series are a different story.

 

The rods sure are skinny. It was meant to get a full dyno tune this week, but this happened Thursday last week, I've already torn the whole engine down, and yes, a window seems more likely, the pistons look clean on top, no signs of detonation. I think the motor was just sitting for a very long time since it's an import from Japan. Super cruddy and gummy inside, cleaned it out best I could. I'll take a few thousands off each top and second rings, clock them appropriately and reinstall everything, thanks for your reply, hopefully I'll have some dyno numbers soon, only aiming for about 250whp.