melovesboost

Talking to a couple friends of mine and they were talking about how Forged pistons expand. but they said that some expand more than others.

Can anyone confirm this? and could you give some more insight on it. do you have to run more piston to wall clearance to allow the expansion?

99B16Si

yes forged pistons expand more than regular oem cast pistons. they do not contain as much silicone as factory cast pistons and you do need to run more piston to wall clearance due to this, how much more is based on the manufactorers recommendations

melovesboost

alright so the sheet that comes with the pistons that gives the Piston to wall clearance is what i should go with or should i run it a little bit looser?

JDogg

most of the time the sheet that comes with pistons will have you running them way too tight. i run at least 0.004 on everything i build, i use wiseco pistons.

. a d a m

In recent years they have reduced expanding alot more, thats why you always tend to see engine builders who have already been at it for a long time build their motors loose.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by melovesboost &raquo;</TD></TR><TR><TD CLASS="quote">alright so the sheet that comes with the pistons that gives the Piston to wall clearance is what i should go with or should i run it a little bit looser?</TD></TR></TABLE>

I'd do it just a tad looser.

melovesboost

So which pistons expand more than others?

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by melovesboost &raquo;</TD></TR><TR><TD CLASS="quote">So which pistons expand more than others? </TD></TR></TABLE>

Any of your standard low silicon forgings. CP, JE, Arias, Wiseco, ETC. SRP and also I believe Supertech make a higher silicon forging which you can run tighter clearances on for the street. The purpose of that is to make the pistons a bit cheaper, as well as have them be quieter on startup.

093turbo16

iTrader: (2)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted92 &raquo;</TD></TR><TR><TD CLASS="quote">

Any of your standard low silicon forgings. CP, JE, Arias, Wiseco, ETC. SRP and also I believe Supertech make a higher silicon forging which you can run tighter clearances on for the street. The purpose of that is to make the pistons a bit cheaper, as well as have them be quieter on startup.</TD></TR></TABLE>

Pretty much covered it

melovesboost

ok that makes more sense... SO JE, Wiesco, Arias, CP, SRP they all have the same amount of Silicone or does it vary by the manufacture?

JDogg

the silicon content isnt the only thing to worry about when figuring in piston expansion... you also have to look at the shape and overall design of the piston

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by melovesboost &raquo;</TD></TR><TR><TD CLASS="quote">ok that makes more sense... SO JE, Wiesco, Arias, CP, SRP they all have the same amount of Silicone or does it vary by the manufacture?
</TD></TR></TABLE>

All the standard "high end" pistons like JE, Wiseco, Arias, CP, and the like are the "low silicon" forgings that need more clearance and might run a bit noisy on start up. SRP and Supertech are the only companies I can think of off the top of my head that produce a higher silicon "quiet" piston for Hondas.

Westrock2000

I had JE in a B20 and for about the first 20 seconds it sounded kinda rough, then it would smooth out real quick.

0morgan@synapse motorsport

i heard the arias are higher silicon content than the cp/wiseco/je's anyone know some more about that?

melovesboost

looks like i started a decent thread.. Id like to hear all the facts. not hear say

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrdthry911 &raquo;</TD></TR><TR><TD CLASS="quote">i heard the arias are higher silicon content than the cp/wiseco/je's anyone know some more about that?</TD></TR></TABLE>

Arias does have some 4032 Alloy (Low Expansion/Higher Silicon Content) pistons but I am fairly certain all of their Honda/Acura pistons are made from the lower silicon content 2618 alloy.

melovesboost

so how much clearance would need to be added to the machining to give them enough room to expand?

doood

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by melovesboost &raquo;</TD></TR><TR><TD CLASS="quote">so how much clearance would need to be added to the machining to give them enough room to expand?</TD></TR></TABLE>

whatever the spec sheet that comes with the pistons calls for