[16v][tech] Dirty intake valves?

[pb1113@hotmail.com (Chris M)]

Hi again,
   I got another piece to the puzzle for ya'all that I found yesterday.  I
was looking through the massive amounts of documentation that came with the
car and I see that a while ago the P.O. took the car in for a broken timing
belt.  Here's my theory: I think the DS valves are bent a little, causing
some back-flow of exhaust gases and depositing them on the backsides of the
valves.  Yes, there are some deposits upstream, in the ports, and I can
clearly see the injector spray pattern in the ports. Why only the DS valves?
I've always assumed that the DS and PS cam lobes were identical in lift and
timing, but maybe the cam grinder at the factory was a little off on the DS
lobes that day or maybe they are not identical by design. When the timing
belt broke, IF the lobes aren't the same, and IF the DS valves were in a
position for piston contact, and IF the PS valves weren't, that would
explain this whole thing.  A lot of "ifs" but that's all I can think of. I
don't know what the faces look like since the head is still on the car.  The
EFI project is soaking up all my money at this time so that head is going to
stay where it is for now.  When I put a new engine in next winter (2L of
course) I'll either send the head out or order a new one.  Then I'll know
for sure what's going on here.  Any more ideas?

Chris

----- Original Message -----
From: "Larry" <rocco16v@netzero.com>
To: "Night Shadow" <soltwede@privateI.com>
Cc: "Dan Bubb" <jdbubb@ix.netcom.com>; "Chris M" <pb1113@hotmail.com>;
<scirocco-l@scirocco.org>
Sent: Sunday, February 17, 2002 9:23 AM
Subject: Re: [16v][tech] Dirty intake valves?


> Chris-
>  Need more information;
> Is it the faces, or the backsides (upstream side), of the DS intake valves
> that are dirty?Or both sides?
> Do just the valves exhibit this, or do the separated ports themselves look
> the same, i.e. DS dirty and PS clean?
>
> Larry  sandiego16V
>
> ----- Original Message -----
> From: Night Shadow <soltwede@privateI.com>
> To: Larry <rocco16v@netzero.com>
> Cc: Dan Bubb <jdbubb@ix.netcom.com>; Chris M <pb1113@hotmail.com>;
> <scirocco-l@scirocco.org>
> Sent: Saturday, February 16, 2002 9:06 PM
> Subject: Re: [16v][tech] Dirty intake valves?
>
>
> >
> > Well....lets atleast hear your opinion on my CCV theory.
> >
> > Eric
> >
> > On Sat, 16 Feb 2002, Larry wrote:
> >
> > > Heck, Dan, I haven't GOT one!!!!   ....for once. :)
> > >
> > > Larry  sandiego16V
> > >   ----- Original Message -----
> > >   From: Dan Bubb
> > >   To: Larry ; Chris M ; scirocco-l@scirocco.org
> > >   Sent: Saturday, February 16, 2002 3:27 PM
> > >   Subject: Re: [16v][tech] Dirty intake valves?
> > >
> > >
> > >   Well, shit! Let's have yours first.
> > >
> > >     ----- Original Message -----
> > >     From: Larry
> > >     To: Chris M ; scirocco-l@scirocco.org
> > >     Sent: Saturday, February 16, 2002 3:44 PM
> > >     Subject: Re: [16v][tech] Dirty intake valves?
> > >
> > >
> > >     Man, I can't wait to hear the theories on this one!!
> > >
> > >     Larry   sandiego16V
> > >       I have my intake off and I was looking at the intake valves
> yesterday and noticed that the right-hand (driver's side) valve in each
port
> is way dirty with some kind of baked-on oil or something.  The passenger
> side valves are all clean as a whistle.  Any idea what could cause this?
My
> first thought is valve seals, but it doesn't make sense that all the ones
on
> the driver's side of each port would be bad.  The engine ran decent when I
> took it off the road, so I don't think anything major is wrong with it,
I'm
> just curious what could cause this...
> > >
> > >       Thanks...
> > >
> > >       Chris M.
> > >       82 8v Scirocco
> > >       88 16v Scirocco
> > >       70 MGB (wife's car)
> > >       76 Chevy Laguna
> > >       http://www.geocities.com/vw16vmp3scirocco/
> > >       pb1113@hotmail.com
> > >
> > >
> >
> > --
> > Eric
> > Northglenn, CO
> >
> > 76 Honda CB400F Super Sport
> > 80 Scirocco (Parts car again, no more DD duty)
> > 81 Scirocco S (2.0 16v swap and complete restoration in progress)
> > 81 Rabbit Truck LX Diesel (THE NEW RIDE)
> > 91 Cabriolet (2.0 Crossflow 8v swap and mechanical rebuild in progress)
> > 00 Golf GL TDI (Katy is driving this for now)
> >
> > "For Aquarians, the physics of loopholes is a perfectly valid science."
> > -Kelli Fox
> >
> >
>
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