Just how bad is..... ***updated***

I agree... call the maker with the job# for piston ID. The builder may be measuring the skirts in the wrong place and/or that may be the design intent of the maker. Or you may want to coat the skirts.

i had my diamond skirts coated, don't know the thickness. $120.00 to do the skirts. as mentioned, that maybe a good option for u. good luck, seeya.

Yes you need new pistons. That is way too much clearence. The pistons will rock too much causing the rings not to ride square in the bore and the ring seal will be horrible. We run .004 in my small block.
Steve

Don, the piston clearances are determined by several things, the piston alloy being the main one Get the job number off of the pistons and call them(JE) to get thier recommendations If they need coating try calling Embee CO., 714-546-6907, to see if they will hard anadyse(SP?) your pistons. I had them do a set several years back to restore the skirts on a set of Ross pistons that where in a motor that the lifters tops failed and the debris hurt the clinder walls and piston skirts. That was a long time ago and the owner has squeezed(sprayed NOS) that motor a lot since then and beat the snout out of it on the street for close to 20,000 miles on pump gas and accoding to him the pistons look like new the last time he looked at them EDITED: I forgot to mention that Embee is a goverment certified aircraft parts maker and repair center, good stuff Make sure you tell them, if you decide to use them,that you want the hard anadising coating, just like the top fuelers use

Are the pistons or the bores out of spec?
Don't know what you have invested in the block but it may be more cost effective to find another.

Definetly find out what the piston manufactor specs are. Some pistons call for much more then others depending on the piston material and make but .010 is a good bit. Ron

i didnt see anyone ask were it loose at.. is it taper? meaning the top of the cylinder has more wear/taper than the bottom..
Like engines with lots of miles?
If its consistent, you could use little bigger bore ring, say .005 or so.. if it's taper it wont matter much... It will run sure... It might slobber and have excess blow by...

I think you know my answer

Spoke with JE Pistons.. the pistons I have are old as they have no engraving on them.. and also, JE would like to see a max clearance of .0045..

So it looks like I will be shopping for new pistons..

Thanks to everyone for their assistance

Don't drink the Kool-Aide! If .007 is acceptable, .010 will be fine with that big of a bore and forged pistons. That difference in clearance isn't going to cause the rings to not seal properly, sure it may not be the absolute best possible but you'll never know the difference if you stop worrying about it. Not having any taper in the bore and setting the end gap on the rings where it needs to be will be the important things, probably .018-.019".

The only identification on the pistons is the forging number.. (or so I'm told) That number is "JE 314F" and is located on the bottom side of the piston..

Being that there is no engraving on the piston, this is suggesting the pistons are pre-2004 as that is when JE started the engraving program.. So not only are we dealing with a piston that fits a little loose in the bore, but its also getting on 7 or 8 years in age..

I dont know if the age means anything towards reliability, but I would hate to toast a motor because I got cheap..

Tried to do a little research for you but all I found is were the numbers should be. Sorry.
http://www.jepistons.com/TechCorner/HowToIdentify.aspx

I will probably get flamed by the you shouldn't do that Mopar crew, but year ago I had a good year going and developed a blow-by issue on an engine that should have been gone through over the past Winter. The funds were not there and I had some choices to make. Try to make another season or sit out the year. I chose to race and like I said had a good season going. When she started puffing smoke I quickly pulled the engine, ripped her down, and took some measurements. .011 clearance so I made some calls to some old time machinists and do you know what they recommended? A fresh hone job and buy some broken sets ( rings set back with missing or broken rings ) and rebuild it with cast rings. At that time all broken sets were set to California so I ordered 3 incomplete sets ( at a great price ) and I put it together. Cast rings only no moly ring. You won't believe how well the engine ran. After the season it became a backup engine that was put to use for years to come. Rant on if you want to but trust me it worked.

Too cool .............My pistons are around .007 this time around and I hear no loose pistons in my motor. Revs nicely and thats w/moly top napier 2nd(both back cut)and med oil rings...........You may coat em for peace of mind although that only lasts so long anyhow.