Squish area; definition. was;Re: What makes a 2 liter [16v]?

[6keb1@qlink.queensu.ca (Kareem)]

Thanks for the clarification! I should have used
"combustion chamber" in my previous posts instead of
"squish area"
Kareem

On Thu, 11 Apr 2002, Dan Bubb wrote:

> Disregarding one really humorous and completely sexist definition
> suggested by one of the listers.....
> Squish area is the AREA (not volume!) in the combustion chamber where
> the piston virtually contacts the cylinder head when the piston is at
> TDC.
> On an 8V the combustion chamber has a flat area on either side of the
> chamber and the piston has a corresponding flat area.
> On a 16V the chamber has a flat area only on the intake side. The piston
> is flat topped, with the exception of the valve clearance pocket, but
> the squish area is only the area where the piston and head are both flat
> in close proximity at TDC.
> See attached GIF for an illustration of squish area. This is for a more
> conventional 16V with equally disposed intake and exhaust valve angles.
> The purpose of the squish area is to force the fuel/air mixture to jet
> out of the area towards the spark plug and generate turbulence for rapid
> combustion.
> The popular misconception appears to be that the squish area is the
> volume that the cylinder contents are squished into when the piston is
> at TDC. Well, this is a volume not an area.
> It's commonly refered to as the "combustion chamber"
> Dan
> Sorry about attaching the file, but it's small and a picture is worth a
> thousand words.
>
>
> Kareem wrote:
> >
> > Dan, we were responding to a 16v question. By squish area
> > I'm referring to the part of the combustion chamber that
> > resides in the piston top when it is a top dead centre.
> > The 2L piston provides a smaller squish area than the 1.8L
> > piston and this results in a compression increase when a 2L
> > block is used underneath the 1.8 head.
> >
> > Kareem
> >
> > On Wed, 10 Apr 2002, Dan Bubb wrote:
> >
> > > 1st. Are you guys talking about an 8V or 16V. If it's an 8V then the
> > > compression doesn't change by sticking a 2.0L block under a 1.8 head.
> > > 2nd. The comment about squish area doesn't make any sense. Please define
> > > squish area so we all know what you think you're talking about.
> > > Dan
> > >
> > > Kareem wrote:
> > > >
> > > > To spell it all out: as Al said, there is a difference in both bore and
> > > > stroke, but the difference in bore is small enough such that the
> > > > combustion chamber in the head of the 1.8 will also match up to the 2.0
> > > > block and work very effectively. Of course, the oil and coolant
> > > > passages match perfectly.. As to the compression ratios of the 2.0 block
> > > > w/ 1.8 head  I think it's around 10.8:1   - the increase over the 10:1 of
> > > > the 1.8L engine being due mostly because of the reduced
> > > > squish area of the 2L pistons. HTH.
> > > >
> > > > On Tue, 9 Apr 2002, Allyn wrote:
> > > >
> > > > > difference is in both bore (82.5 vs. 81 mm), and in stroke (92.8 vs. 86.4).
> > > > > Al