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how feasible is an 8v piston swap?(8.5:1 to 10:1)
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Brian,
You are right I made an assumption and I know better.=20
I should remember not to post any replies at 5 am as my brain isn't =
working yet.
Rick Alexander - the older I get the more frequent the brain farts.
----- Original Message -----=20
From: Decker=20
To: Scirocco email list=20
Sent: Saturday, December 14, 2002 10:24 AM
Subject: Re: how feasible is an 8v piston swap?(8.5:1 to 10:1)
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.
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
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<DIV><STRONG>Brian,</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>You are right I made an assumption and I know better.=20
</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>I should remember not to post any replies at 5 am as my =
brain isn't=20
working yet.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Rick Alexander - the older I get the more frequent the =
brain=20
farts.</STRONG></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dboisfort@myhome.net =
href=3D"mailto:boisfort@myhome.net";>Decker</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 email list</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, December 14, =
2002 10:24=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><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=20
10 to 1 compression. The late 80's 8 valve RD engine in Golf GTI's and =
GLI's=20
plus others. Also you can run 10 to 1 compression quite well on the =
street=20
without a knock sensor if you use premium gas. I have a 1979 MK 1 =
Scirocco.=20
I'm running without the knock sensor an 85 Audi 10 to 1 hydraulic 8 =
valve=20
engine that had a knock sensor in the Audi. I am running it with a =
straight=20
CIS system from an 84 GTI. The distributor is an earlier points setup =
running=20
straight mechanical advance ( no vacuum advance or retard ) with 37 =
degrees=20
total advance. It ran great with the stock cam and a whole lot better =
with the=20
German 272 cam I bought from AVS in Adna WA. My VW mechanic has used =
this=20
formula for years. He put an RD engine ( 10 to 1, </FONT><FONT =
size=3D2> 8=20
valve ) in a 1980 Rabbit pickup that was formally diesel and the =
customer ran=20
the 10.1 engine with a carburetor. The conversion was made 6 or 7 =
years ago=20
and the truck is still running. </FONT></FONT></DIV>
<DIV><FONT color=3D#0000ff size=3D2> My 85 Audi 8 =
valve 1800 10=20
to 1 engine had 102 horsepower listed stock in. the Audi. In my 79 =
Scirocco I=20
am running it with a Tectonics long dual down pipe to a 2 and one half =
in=20
exhaust system with 14 inch turbo muffler with no cat, a 272 cam, =
straight=20
mechanical advance ignition . So I'm pretty sure I'm making almost as =
much=20
horsepower as a stock 1800 16 valve. We will see this spring. I have a =
Quaife=20
differential in it and this thing gets with the project. I will go to =
the=20
drags as soon as they open here in the Northwest. My next engine will =
be an=20
ABA tall block 2 liter with a ported and polished 8 valve 84 GTI solid =
lifter=20
head. You folks can keep your 16 valve engines. My engine may not have =
quite=20
as many horses but all I have to worry about is a coil =
a mechanical=20
advance distributor with points, straight CIS, spark plugs and gas. If =
it=20
isn't running even this dumb old Dutchman should be able to find the =
problem .=20
</FONT><FONT color=3D#0000ff size=3D2>Just my thoughts I'm sure others =
will differ=20
and they are probably 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"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=3Dralexander03@snet.net =
href=3D"mailto:ralexander03@snet.net";>Rick=20
Alexander</A> </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 2:53=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: how feasible is =
an 8v=20
piston 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=20
have them right but, here are the ones that come to=20
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=20
and I believe a different oil pump. Now consider the knock box that =
you=20
don't have on the 8v but would need for the 10/1 compression ratio. =
You=20
would probably be better off finding a 16v or 2.0l and starting =
over. Since=20
you only have 8k on the 8v your probably best off just living with=20
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"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=20
2:49 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=20
rehone? Should I replace the rod bearings and bolts =
even though=20
they only have 8k? How much more HP can I expect by going to=20
10:1? Should I use the 10:1 wrist pins or the current =
ones? Is=20
this a very common mod?(that's usually a fair indicator of if it's =
worth=20
it or not). Wow that was a lot of questions! =
thanks in=20
advance, every little bit 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></BLOCKQUOTE></BODY></HTML>
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