[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

how feasible is an 8v piston swap?(8.5:1 to 10:1)



This is a multi-part message in MIME format.

------=_NextPart_000_001A_01C2A335.1DB831C0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

I'm not going to have all of the do's and don'ts or probably have them =
right but, here are the ones that come to mind.

The 8v has the combustion chamber in the cylinders. The 16v has the =
combustion chamber in the head.
Putting the 16v pistons in the 8v will cause valve interference with the =
pistons. You could put a 16v head on but there are other things specific =
to the 16v like the rods, the under piston squinters and I believe a =
different oil pump. Now consider the knock box that you don't have on =
the 8v but would need for the 10/1 compression ratio. You would probably =
be better off finding a 16v or 2.0l and starting over. Since you only =
have 8k on the 8v your probably best off just living with it.

Sorry,

Rick Alexander

----- Original Message -----=20
  From: Robbie Cotner=20
  To: scirocco-l@scirocco.org=20
  Sent: Saturday, December 14, 2002 2:49 AM
  Subject: how feasible is an 8v piston swap?(8.5:1 to 10:1)


  Hey all,=20

  I rebuilt my 1.8 JH 8v engine about 8k ago.  Now I wish I would've =
installed some 10:1 pistons.  I recently came across a set for $50(is =
that a good price?), and was wondering how feasible it would be to =
install them in my '83 Scirocco.  Can I just remove the head and oil =
pan, disconnect the rods, push the old pistons(not oversized) up out the =
block, then put the 10:1 pistons(think they're from a GTI) with new =
rings onto the old rods and reassemble?  Would I have to rehone?  Should =
I replace the rod bearings and bolts even though they only have 8k? How =
much more HP can I expect by going to 10:1?  Should I use the 10:1 wrist =
pins or the current ones?  Is this a very common mod?(that's usually a =
fair indicator of if it's worth it or not).  Wow that was a lot of =
questions!  thanks in advance, every little bit of info/opinions helps!- =


  Rob =20





-------------------------------------------------------------------------=
-----
  Do you Yahoo!?
  Yahoo! Mail Plus - Powerful. Affordable. Sign up now

------=_NextPart_000_001A_01C2A335.1DB831C0
Content-Type: text/html;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 5.50.4030.2400" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><STRONG>I'm not going to have all of the do's and don'ts or =
probably have=20
them right but,&nbsp;here are the ones that come to mind.</STRONG></DIV>
<DIV><STRONG></STRONG>&nbsp;</DIV>
<DIV><STRONG>The 8v has the combustion chamber in the cylinders.=20
</STRONG><STRONG>The 16v has the combustion chamber in the =
head.</STRONG></DIV>
<DIV><STRONG>Putting the 16v pistons in the 8v will cause valve =
interference=20
with the pistons. </STRONG><STRONG>You could put a 16v head on but there =
are=20
other things specific to the 16v like the rods, the under piston =
squinters and I=20
believe a different oil pump. Now consider the knock box that you don't =
have on=20
the 8v but would need for the 10/1 compression ratio. You would probably =
be=20
better off finding a 16v or 2.0l and starting over. Since you only have =
8k on=20
the 8v your probably best off just living with it.</STRONG></DIV>
<DIV><STRONG></STRONG>&nbsp;</DIV>
<DIV><STRONG>Sorry,</STRONG></DIV>
<DIV><STRONG></STRONG>&nbsp;</DIV>
<DIV><STRONG>Rick Alexander<BR></STRONG></DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3Drobw_z@yahoo.com href=3D"mailto:robw_z@yahoo.com";>Robbie =
Cotner</A>=20
  </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dscirocco-l@scirocco.org=20
  href=3D"mailto:scirocco-l@scirocco.org";>scirocco-l@scirocco.org</A> =
</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, December 14, =
2002 2:49=20
  AM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> how feasible is an 8v =
piston=20
  swap?(8.5:1 to 10:1)</DIV>
  <DIV><BR></DIV>
  <P>Hey all,=20
  <P>I rebuilt my 1.8 JH 8v engine about 8k ago.&nbsp; Now I wish I =
would've=20
  installed some 10:1 pistons.&nbsp; I recently came across a set for =
$50(is=20
  that a good price?), and was wondering how feasible it would be to =
install=20
  them in my '83 Scirocco.&nbsp; Can I just remove the head and oil pan, =

  disconnect the rods, push the old pistons(not oversized) up out the=20
  block,&nbsp;then put the 10:1 pistons(think they're from a GTI) with =
new rings=20
  onto the old rods and reassemble?&nbsp; Would I have to rehone?&nbsp; =
Should I=20
  replace the&nbsp;rod bearings and bolts even though they only have 8k? =
How=20
  much more HP can I expect&nbsp;by going to 10:1?&nbsp; Should I use =
the 10:1=20
  wrist pins or the current ones?&nbsp; Is this a very common =
mod?(that's=20
  usually a fair indicator of if it's worth it or not).&nbsp; Wow that=20
  was&nbsp;a lot of questions!&nbsp; thanks in advance, every little bit =
of=20
  info/opinions helps!-=20
  <P>Rob&nbsp; </P>
  <P><BR>
  <HR SIZE=3D1>
  Do you Yahoo!?<BR><A=20
  =
href=3D"http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com";>Yaho=
o! Mail=20
  Plus</A> - Powerful. Affordable. <A=20
  =
href=3D"http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com";>Sign=
 up=20
  now</A></BLOCKQUOTE></BODY></HTML>

------=_NextPart_000_001A_01C2A335.1DB831C0--