[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_0026_01C2A341.E7A13A20
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Hi Rick;
Why would you assume that the 10 to 1 pistons are from a 16 valve. =
Many 1800 8 valve engines have 10 to 1 compression. The late 80's 8 =
valve RD engine in Golf GTI's and GLI's plus others. Also you can run 10 =
to 1 compression quite well on the street without a knock sensor if you =
use premium gas. I have a 1979 MK 1 Scirocco. I'm running without the =
knock sensor an 85 Audi 10 to 1 hydraulic 8 valve engine that had a =
knock sensor in the Audi. I am running it with a straight CIS system =
from an 84 GTI. The distributor is an earlier points setup running =
straight mechanical advance ( no vacuum advance or retard ) with 37 =
degrees total advance. It ran great with the stock cam and a whole lot =
better with the German 272 cam I bought from AVS in Adna WA. My VW =
mechanic has used this formula for years. He put an RD engine ( 10 to 1, =
8 valve ) in a 1980 Rabbit pickup that was formally diesel and the =
customer ran the 10.1 engine with a carburetor. The conversion was made =
6 or 7 years ago and the truck is still running.=20
My 85 Audi 8 valve 1800 10 to 1 engine had 102 horsepower listed =
stock in. the Audi. In my 79 Scirocco I am running it with a Tectonics =
long dual down pipe to a 2 and one half in exhaust system with 14 inch =
turbo muffler with no cat, a 272 cam, straight mechanical advance =
ignition . So I'm pretty sure I'm making almost as much horsepower as a =
stock 1800 16 valve. We will see this spring. I have a Quaife =
differential in it and this thing gets with the project. I will go to =
the drags as soon as they open here in the Northwest. My next engine =
will be an ABA tall block 2 liter with a ported and polished 8 valve 84 =
GTI solid lifter head. You folks can keep your 16 valve engines. My =
engine may not have quite as many horses but all I have to worry about =
is a coil a mechanical advance distributor with points, straight CIS, =
spark plugs and gas. If it isn't running even this dumb old Dutchman =
should be able to find the problem . Just my thoughts I'm sure others =
will differ and they are probably right
Brian Decker
Western Washington
----- Original Message -----=20
From: Rick Alexander=20
To: scirocco-l@scirocco.org=20
Sent: Saturday, December 14, 2002 2:53 AM
Subject: Re: how feasible is an 8v piston swap?(8.5:1 to 10:1)
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.
=20
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.
=20
Sorry,
=20
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_0026_01C2A341.E7A13A20
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 content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.2919.6307" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#0000ff size=3D2>Hi Rick;</FONT></DIV>
<DIV><FONT color=3D#0000ff><FONT size=3D2> Why would =
you assume=20
that the 10 to 1 pistons are from a 16 valve. Many 1800 8 valve engines =
have 10=20
to 1 compression. The late 80's 8 valve RD engine in Golf GTI's and =
GLI's plus=20
others. Also you can run 10 to 1 compression quite well on the street =
without a=20
knock sensor if you use premium gas. I have a 1979 MK 1 Scirocco. I'm =
running=20
without the knock sensor an 85 Audi 10 to 1 hydraulic 8 valve engine =
that had a=20
knock sensor in the Audi. I am running it with a straight CIS system =
from an 84=20
GTI. The distributor is an earlier points setup running straight =
mechanical=20
advance ( no vacuum advance or retard ) with 37 degrees total advance. =
It ran=20
great with the stock cam and a whole lot better with the German 272 cam =
I bought=20
from AVS in Adna WA. My VW mechanic has used this formula for years. He =
put an=20
RD engine ( 10 to 1, </FONT><FONT size=3D2> 8 valve ) in a 1980 =
Rabbit pickup=20
that was formally diesel and the customer ran the 10.1 engine with a =
carburetor.=20
The conversion was made 6 or 7 years ago and the truck is still running. =
</FONT></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2> My 85 Audi 8 =
valve 1800 10 to=20
1 engine had 102 horsepower listed stock in. the Audi. In my 79 Scirocco =
I am=20
running it with a Tectonics long dual down pipe to a 2 and one half in =
exhaust=20
system with 14 inch turbo muffler with no cat, a 272 cam, straight =
mechanical=20
advance ignition . So I'm pretty sure I'm making almost as much =
horsepower as a=20
stock 1800 16 valve. We will see this spring. I have a Quaife =
differential in it=20
and this thing gets with the project. I will go to the drags as soon as =
they=20
open here in the Northwest. My next engine will be an ABA tall block 2 =
liter=20
with a ported and polished 8 valve 84 GTI solid lifter head. You folks =
can keep=20
your 16 valve engines. My engine may not have quite as many horses but =
all I=20
have to worry about is a coil a mechanical advance distributor with =
points,=20
straight CIS, spark plugs and gas. If it isn't running even this dumb =
old=20
Dutchman should be able to find the problem . </FONT><FONT =
color=3D#0000ff=20
size=3D2>Just my thoughts I'm sure others will differ and they are =
probably=20
right</FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2>Brian Decker</FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2>Western Washington</FONT></DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:ralexander03@snet.net"; =
title=3Dralexander03@snet.net>Rick=20
Alexander</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:scirocco-l@scirocco.org"=20
title=3Dscirocco-l@scirocco.org>scirocco-l@scirocco.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, December 14, =
2002 2:53=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: how feasible is an =
8v piston=20
swap?(8.5:1 to 10:1)</DIV>
<DIV><BR></DIV>
<DIV><STRONG>I'm not going to have all of the do's and don'ts or =
probably have=20
them right but, here are the ones that come to =
mind.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>The 8v has the combustion chamber in the cylinders.=20
</STRONG><STRONG>The 16v has the combustion chamber in the=20
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=20
I believe a different oil pump. Now consider the knock box that you =
don't have=20
on 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> </DIV>
<DIV><STRONG>Sorry,</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Rick Alexander<BR></STRONG></DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; =
MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:robw_z@yahoo.com"; title=3Drobw_z@yahoo.com>Robbie =
Cotner</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:scirocco-l@scirocco.org"=20
title=3Dscirocco-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. Now I wish I =
would've=20
installed some 10:1 pistons. 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. Can I just remove the head and oil =
pan,=20
disconnect the rods, push the old pistons(not oversized) up out the=20
block, then put the 10:1 pistons(think they're from a GTI) with =
new=20
rings onto the old rods and reassemble? Would I have to =
rehone? =20
Should I replace the rod bearings and bolts even though they =
only have=20
8k? How much more HP can I expect by going to 10:1? =
Should I use=20
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=20
that was a lot of questions! thanks in advance, every =
little bit=20
of info/opinions helps!-=20
<P>Rob </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!=20
Mail Plus</A> - Powerful. Affordable. <A=20
=
href=3D"http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com";>Sign=
up=20
now</A></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
------=_NextPart_000_0026_01C2A341.E7A13A20--