new head impressions/problems (of course)

[rabbit16v@attbi.com (Dave Ewing)]

1.  The cam gear should be at the same place as the stock cam gear.  A
decked head (max factory decking is something around 39 - 40 thousandths,
any more than that this won't apply) should not throw the timing off by a
whole tooth!  Maybe (if decked 40 thousandths) half a tooth but not a whole
tooth.  Set the adjustable cam gear to zero, line everything up on TDC and
adjust the cam gear accordingly.  Be careful though because moving the cam
on a decked head even one tooth off could cause interference (don't ask how
I know this!!).  Probably the best way to set your motor up is to get a
degree wheel/pulley on the crank and find out where the pistons hit with the
plugs out so you have NO compression to deal with.  Then you'll be able to
know the area you have to work with.  I am suspecting though that you are
actually only off about half a tooth.  Once you have the cam set where it
should be you can start playing with power curves and such.

2.  Get an aftermarket fuel system.  No, kidding, actually you'll have to
track everything down.  What I mean by this is that you need to remember
that you are working with stock wires, connectors, etc. and that they will
have more resistance than new.  Plus, grounds will and can cause problems in
this area too!  Also, another contraversy on this list, how did you install
the O2 sensor?  If it was the entire assy, then great but if it was just the
sensor with a crimp connector, I reccomend installing it according to the
way it came, with the crimp connector and the heat shrink.  This is how
Bosch, the manufacturer of the O2 sensor, reccomends and why the pre-install
a crimp connector and include a piece of heat shrink with the replacement O2
sensor.

3.  Your cams will make the idle pretty rough but consistant.  You should
hear a consistancy in the lumpiness of the idle because of the cams if
everything else is operating correctly.  Of course, as you have already
noted, you do need to take care of the other problems before you deal with
the idle but at the same time, a screwy idle can mess with a bunch of other
settings including timing!

4.  Who installed the head?  You?  A shop?  Was the oil changed after the
install?  I know that a lot of times you don't think coolant will get into
the oil especially if you drain the cooling system first but after replacing
a head the oil should ALWAYS be changed along with the filter.  If you have
done this and you are still getting coolant in the oil AND you know it isn't
from condensation then you more than likely have a headgasket problem or a
crack somewhere.  I hope that during the porting and polishing that a water
jacket wasn't compromised!!!  Not to worry, though, if you can't find any
other problems then you can have the head pressure tested and welded which
is a lot cheaper than doing another head!  I would suspect residual or
condensation myself but I didn't do the work!!

Let us all know how this plays out as I, at least, am curious!!  Hope some
of this helps!  And, just so you know, this information is from research and
experience and I, by no means, take responsibility for anything that happens
to your motor.  One of the downsides to doing work yourself is that you have
to fill in your own grey areas by experimentation just like the engineers
do!

Dave

> finally finished installing my new head today. 1.8 16v P&P, decked .012",
> schrick 268/276.  first-it feels fast; good midrange. surprisingly, it
loses
> steam at about 6k. at my little timing stretch of road, it was just about
> the same speed as my old head (1.8 w/ euro cam).  several problems:
> 1. timing--i'm pretty sure i'm off with the timing.  when i timed it by
the
> cams, the sprocket (kent adjustable) mark was back toward the firewall by
a
> tooth. not sure why. brett c said this was because of the decked head, but
i
> still don't understand why the cams would be on, but the sprocket
wouldn't;
> the sprocket is connected to the cams. i timed it to the sprocket mark.
> tomorrow i'll try moving it a tooth.
> 2. mixture is a constant 10ma. i hate this. just replaced o2 sensor a
couple
> of mos ago, and had a problem with the connector to the heating wires. i
> don't think that's the issue now.  measuring o2 voltage directly, my
needle
> barely moves. but it does move. analog crap ammeter. i think i'll break
down
> and buy digital soon. i richened by 1/4 turn just to be safe.  can
anything
> else cause this constant 10ma besides o2 sensor and ecu? turning the screw
> doesn't seem to affect dpr at all.
> 3. idle is crap. expected this, but if i come off the gas hard at a light,
i
> stall. can't really deal w/ this till i straighten out the above.
> 4. there's oil in the coolant. yikes. not a ton, but enough to make me
> worried. no white smoke, no water in the oil. i probably got it in the
> coolant passages with all my messing around. did a compression test and
got
> 140-150-150-130. this was with the timing off a couple of teeth, which i'm
> guessing is the cause of the low compression. should've repeated, but i'm
> lazy.
>
> i think that's it. i have a fuel enrichment box that's been unhooked (it
was
> faster without it). once i get timing/mixture right, i'll hook it back up.
> any suggestions on how i should proceed/what i should shoot for for idle
> specs?
> tia,
>
> -Michael Abatzis<--takes apart perfectly working cars, and makes it so
they
> don't work as well.
> Hotlanta! GA
> 1988 Scirocco 2L 16v RIP-->parting, prelim web site, but not taking orders
> yet: www.learnlink.emory.edu/~mabatzi/mikes_page1.html
> 1987 Scirocco 2L 16v...
>
>
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