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16v head on a 1.7L engine



Scott,
    Yea, but enough to drop THAT low???
Al

----- Original Message -----
From: "Scott F. Williams" <sfwilliams@home.com>
To: "Allyn" <amalventano1@home.com>; <jester@westfailure.net>; "Jerry
Carter" <jerry.carter@shaw.ca>
Cc: "Scirocco List" <scirocco-l@scirocco.org>
Sent: Thursday, January 10, 2002 6:47 PM
Subject: RE: 16v head on a 1.7L engine


> >     Umm, scott, the only reason compression goes up with 1.8 head + 2.0
> > block is that the 2.0 block has less area with piston at tdc than the
1.8
> > block does. The 2.0 head has more area under the valves than the
> > 1.8.
>
> Er, Allyn? You're incorrect, bud. :^) First of all, it ain't a 2.0l versus
> 1.8l issue. The combustion chamber shapes are different from 8v to 16v
> motor. Just look at the head and pistons. The 8v has a relatively little
> volume in the head itself but the pistons are dished. Whereas, the 16v has
a
> near hemi-spherical combustion chamber and the pistons are flat. The only
> exception that I know of is the oldskool 8v "Heron" head which also had
flat
> pistons.
>
> If you install an 8v head on top of a 1.8l *or* 2.0l 16v bottom end, the
> compression ratio will shoot way up (makes for a nice NA race-only motor).
> And, if you drop a 16v head on top of a 1.8l *or* 2.0l 8v block, the CR
will
> drop. These are facts!
>
> > P.S. is that your gti that shows up for like 1 second in those
> > rally videos?
>
> I'd have to guess not. The footage in that flick was taken up in Canada.
To
> date, I have never rallied up there. I was planning on gettin' sideways up
> there this season, but... well... you know the story. :^)
> --
> Scott F. Williams
> NJ Scirocco nut
> Golf GTI 16v rollycar
> Mazda 323 GTX turbo assaulted vehicle
> '99 Subaru Impreza 2.5 RS (coming soon)
> ClubVAC: "Roads found. Drivers wanted."
>
> Check out our rally team's website!
> http://www.usrallyteam.com
>
>