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Compression question



At 04:49 PM 5/7/2003, worldcyclist wrote:
>I worked at a shop and we'd often get Jetta's (the most commonly abused car
>for that particular area- Berkely CA) with compression up to 230psi that
>would nock and ping like crazy.  We used a roll around machine that would
>plug into the fuel system to clean out the carbon buildup, and reduce the
>PSI back to normal level.
>
>At 190-215 either the engine is not stock or it's well carbonized. However I
>don't have my Bently manual in front of me......

The 1.8 had 40k on it, with carbon deposits.  No pinging, 109hp on the 
dyno, 36mpg on the highway.
The 2.0 had 3,000 miles on it, no carbon deposits obviously.  121hp on the 
dyno, 37mpg on the highway.

My current 2.0 has unknown mileage, but was apart about 150 miles ago and 
had no carbon buildup and a brand new 2.0 head.  Its readings were the 
highest of the bunch - 210-215 across the board.

I have a feeling that my compression tester reads a little high... but I 
just the "comparitive" method.  A 16V pushing 230psi on my compression 
tester would merit closer inspection -- as would one blowing only 170psi.

FWIW, with a Schrick 260' intake advanced 8' (IIRC) , I got only 150 across 
the board.  Guess that was a little too much advance, eh? :)

Jason





>Gary
>
>Jason wrote:
>
> > Both my 1.8 and 2.0 16V give between 190 and 215psi cold.
> > Jason
> >
> > At 02:46 PM 5/7/2003, worldcyclist wrote:
> > >I've got some firsthand experience that might be helpful.
> > >My 1.8 16V with stock cam timing gave 150psi doing a compression test.
> > >With the cam advanced 8* it was 175psi. Otherwise it's 10-1 in terms of
> > >ratios.
> > >The JH engine I had was 135psi or 8.5-1.
> > >The Alfa with 9.5-1 gives me 173 psi with stock cams and timing.
> > >
> > >An interesting site is www.smokemup.com
> > >they have GUI programs to play with stuff like this, plus more.
> > >
> > >Gary
> > >87 16V Scirocco (FS $975)
> > >80 Callaway Stage 3 Rocco
> > >91 Alfa Romeo 3.0 V6 5spd, lowered
> > >
> > >Message: 57
> > >From: "Scourge" <scourge@cogeco.ca>
> > >To: "Rocco list" <scirocco-l@scirocco.org>
> > >Subject:
> > >Date: Mon, 5 May 2003 18:33:42 -0400
> > >
> > >This is a multi-part message in MIME format.
> > >
> > >------=_NextPart_000_0007_01C31334.DABF40A0
> > >Content-Type: text/plain;
> > >         charset="iso-8859-1"
> > >Content-Transfer-Encoding: quoted-printable
> > >
> > >Hey
> > >
> > >Just curious, what the stock compression on 16v's?  2.0 and 18
> > >And what about a stock jh?
> > >
> > >I think it's in the high 8's or low 9's for the jh. Does a 1.8 16v head
> > >=
> > >on a 2.0 16v actually increase compression?
> > >
> > >
> > >thanx
> > >
> > >  -The George
> > >
> > >