over here it seems like there are some more experienced engine builders than my VW fourm so ill ask here too.......
that are exceptiable clearances???
my pistons are je 83mm(3.268")
my cylinder diamater is 3.287"(83.489mm)
the cylinder wall varies by 1 onethousand of and inch measuring in about 6 diffrent places....
so that leaves about 10.5 thousandths of and inch on any side of the piston....is this exceptiable???
i havent measured the piston in multiple places yet,but what im trying to do is re-ring a motor and hoping that these specs are gonna be exceptiable....i still need to hoan out the cylinder so i would expect that the diamater of the cylinder would increase by 1 or 2 thousandths....yes?

this is a turbo motor also if it makes a diffrence........

 

were these pistons recently run in the engine? right now you have .0190" of piston to wall clearance, which happens to be way too much. it seems like you need .020" over pistons, if it is standard bore now. where are you measuring the pistons? with j/e pistons, you need to measure .500"(half an inch) up from the bottom of the skirt. check your numbers again. if the bore size varies a thousandth of an inch(.0010"), then this is not good. its ok for it to vary a couple of tenths of an inch(.0002"). the bore should be straight and round, and should't have any more then half a thousandth(.0005") out of round or taper.

when re-ringing, only a de-glaze is needed, which only takes a couple tenths.

 

yes they were recently ran in the motor...about 10000 miles on them

it is not the standard bore....standard is 82.5mm
i just measured the piston 1/2 inch from the skirt and it was 3.283" and the bore was 3.287".....is .005"diffrence ok???
the .001" diffrence in the bore was probally closer to .0005" i was rounding up and it was in only one place out of the 6 diffrent places i measured the bore....

is all this ok???

 

No way jose... 10.5 thousands of an inch piston to wall?? no way man.. your done.. that motor will have alot of blowby.. with forged pistons you generally want to have about .003-.004 thousands of an inch p-w... get bigger pistons. or resleeve the block and tell your machine shop the specs you want. measure the piston from the sideskirt though. not the top. its gets smaller up there.. good luck!! even though your a vw guy..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MHRacing-310 &raquo;</TD></TR><TR><TD CLASS="quote">No way jose... 10.5 thousands of an inch piston to wall?? no way man.. your done.. that motor will have alot of blowby.. with forged pistons you generally want to have about .003-.004 thousands of an inch p-w... get bigger pistons. or resleeve the block and tell your machine shop the specs you want. measure the piston from the sideskirt though. not the top. its gets smaller up there.. good luck!! even though your a vw guy.. </TD></TR></TABLE>
it was only .005" diffrence at the sideskirt......im gonna try it anyways,it takes me 2 to 3 hours to pull the hole thing down anyways......i got nothing to lose and if it doesnt work,im gonna be done for the season anyways....


"even though your a vw guy.. "
hell,if i know what i know now after building 2 hondas for people,i would have played with one along time ago,but hell,300WHP in a 1900 pound car if fun no matter who made it :

 

thats still .001-.002 thousands of an inch bigger and out of round then what the tollerances should be at.. you will definetly have blow by and significant loss in hp. if you got no choise.. fuckit.. ***** to the wall.. just dont break a tranny.. i know the vw's i have had to race against break alot of those things..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MHRacing-310 &raquo;</TD></TR><TR><TD CLASS="quote">thats still .001-.002 thousands of an inch bigger and out of round then what the tollerances should be at.. you will definetly have blow by and significant loss in hp. if you got no choise.. fuckit.. ***** to the wall.. just dont break a tranny.. i know the vw's i have had to race against break alot of those things..</TD></TR></TABLE>
hahaha true,this is why i pulled it apart in the first place.....80 lbs on compressom is a little low....lol.....i was filling up a catch can after 2 beet runs....

trannys.......dont even get me started,2 in a year