Pits....lots of them.
#4


What's larger than the sum of the thicknesses of ten human hairs, and smaller than the thickness of a finger nail?
#1


In case you can't squint hard enough to read the numbers, it's .010"...at least 3x too much clearance on those pistons.


Normal? Probably not...
http://portfolio.iu.edu/bchang...I.AVI
-Right click, save as

Pissed off pistons in an unhappy bore.
#1




What's missing in this picture?
#3 foreground, #2 background


A closer look. Can you see it now?
#3

#2


Side-to-side piston rocking. That's quite a bit IMO.
Measured on #3.




What else can go wrong?
#1




#3 spark plug died


The motor had good compression a year ago at 260psi across the board and dyno'd 190whp and 130lb*ft in March 2003. We pulled the motor apart to replace the head gasket a second time in one year and found all of the above.

The pistons are standard 81mm bore and have only been in the car for 9k miles. Pistons were not clearanced when initially installed. Check your clearances before throwing parts together guys.


Modified by IN VTEC at 1:29 PM 9/30/2003

 

I say send the pistons to me.. I'll check them out for ya! Everytime I see the cosworth design.. I get a happy tent! That's fukd that the tolerances are messed up.. who put the motor together?

 

My roommate did it about a couple of years ago before he moved here from NY.

What's coincidentally funny is that his dad just wrecked a cylinder bank full of valvetrain items during a track event in his 80's 911. They'll both be doing winter rebuilds.

After discussing things with him and putting compression ratio, reliability and economic feasibility as priorities, he'll be going with .25OS PCTX pistons b/c that's the only OEM Honda piston that will get him close to the CR of the JUN's. He used the stock rods with the JUN pistons anyways, so there's no concerns about having to modify the PCT's to accept a spiro-lock.

 

OS PCT's are the safe reliable way to go, sorry to hear about that, good luck with the rebuild

-sander

 

Thanks. This one will last more than 9k.

 

would my motor need to be bored or rehoned when i put higher compression pistons in it?? sorry to rob the thread, just wondering

 

you didnt notice you had ruined spark plugs till you tore the motor apart???

 

damb hommie that sucks, you may want to hone it out man just to be on the safe side before installing new pistons

 

Didn't misfire, and even if it did, the car's too damn loud to notice it anyways.

 

well living in switzerland the past 2 months with one more to go, i would have to say that the cheese is much better than those pistons.
sorry is that offends anyone.

 

Looks like they may have been too tight to begin with.

 

damn the sucks


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JunIntegra &raquo;</TD></TR><TR><TD CLASS="quote">would my motor need to be bored or rehoned when i put higher compression pistons in it?? sorry to rob the thread, just wondering</TD></TR></TABLE>

just do get it honed even if it looks fine.

 

INVTEC: this isn't your new motor that you are rebuilding is it? Bro I hope it isnt.

I just fucked a piston ring and god only knows how. So I'm spending all this Christmas break rebuilding myself.

 

No. Different motor.

The one in all of the buildup posts is a JDM B18C block with PCT pistons and P72 rods.

This is my other roommate's motor. B18C5 motor that he put JUN pistons into back when he lived in NY.

Are you puffin' lots of smoke?