patSS/00

iTrader: (6)

I have an LS1 block that's been freshly honed .010 and new flat top pistons. The pistons are all .002-.003 under the deck, but one (#8) is .000 on the left side and .002-.003 on the right side. I'm measuring with a machinists straight edge and feeler gauges. What does this mean? The block deck itself is flat. The opposite piston #7 is level. Is there a spec for this, and should I just ignore it?

Ls7colorado

iTrader: (3)

the pistons will have a SLIGHT rock to them, try measuring how much each piston will rock side to side

patSS/00

iTrader: (6)

OK, well I thought they could only rock top to bottom, not side to side.

Edit: You are right!! I was able to push down on that side, now got at least .0015 gap on that side.
Thank you!

Should have realized, there couldn't ever be "piston slap" if the pistons couldn't rock side to side.

Ls7colorado

iTrader: (3)

no problem!

00pooterSS

iTrader: (40)

Also, you have to rock them and add the measurements then divide by 2 to get the out of the hole measurement.

Sounded really off when you said they are all in the hole. They shouldn't be, especially if the block was decked.

patSS/00

iTrader: (6)

Block was not decked. The stock pistons were about .007 out of the hole. The new pistons are .010 shorter than stock, so they end up being .003 in the hole.
Both Mahle and Sealed Power replacement flat top pistons are only available as .010 lower compression height compared to the originals. I even called Mahle to verify they no longer make the original stock height pistons, even though they're listed in their catalog.

00pooterSS

iTrader: (40)

Gotcha. For some reason I thought you said in the first post the block was decked, I just ran **** together that wasn't there apparently.