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A problem installing 268 cams

From gti-vr6-owner@dev.tivoli Wed Jun 17 11:45 CDT 1998
From: Bob Tillman <bobt@p-vector>
To: Arthur Emerson <emerson@eideti>, Chris Franson <cfranson@neca>,
Subject: [gti-vr6] 268s are in! (long)
Date: Wed, 17 Jun 1998 12:33:57 -0400
 
Yo!  The bottom line: the car runs great!  And thanks to Tom and his
wife for putting me up (and putting up with me) at their place near
Philly over the weekend, and especially for the help in putting the darn
things in.

The much longer story: It took us two whole days to finally get the job
done.  The first time.  We started on Saturday morning, worked until
10pm or so, and continued on Sunday morning.  By about 7pm on Sunday we
were ready to try it.  Fired it up, and horrible noises ensued!  I shut
it down after a second.  It sounded to me like the timing chain was
dragging, or some such.  But it did run until I shut it down!

Sit and think a minute: what could have gone wrong?  Oil not up to
pressure yet?  Try it again.  It sort of runs, but misses a lot.  Shut
it down and think again.  What could it be?  Try again, and it doesn't
even fire.  And there's this rapping sound also...

By this time it's into Sunday evening, I'm due at a business meeting in
New Hampshire the following morning (an 8-hour drive) and my car is
broken.  Consider calling Todd to see if he could schedule the car, and
taking the train back to Boston.  Wonder how many bent valves there
are.  Can't decide if I should slit my wrists on Tom's property, or wait
until I'm on the train.  I figure Tom's wife would probably appreciate
it if I could wait until I was on the train.

Meanwhile, we check for spark: present!  And big gas smell too.  The OBD
tool can talk to the ECU, so that's running.  It also says that it's
running at 350 RPM while it's cranking, so the crank and/or cam position
sensors must be OK.  (I guess it wouldn't spark either, otherwise.)
When it cranks, I can feel a breeze coming out of the tailpipe, so it is
pumping air.  Gas, spark, air flow; what's left?  Cam timing?  Broken
sensor?  Messed up wiring?  We figured we should check the cam timing.
OK.  Let's take it apart again.  Meanwhile, Todd called us back and had
reassuring words that the motor should run even if all but the crank
position sensor is hooked up.  So it must be cam timing (or bent valves
on all cylinders!).

Sure enough, the cams were off (late) by two teeth (or so).  And Todd's
suggested test for bent valves (do lifters retract all the way when you
turn the motor?) indicates no damage.  Our theory: (1) I didn't properly
take the slack out of the tension side of the chain when setting the
timing, so it was late by one tooth to start with.  (2) Shutting down
the motor after one second didn't give the oil-fed chain tensioner
enough time to pump up, so during shutdown it jumped another tooth or
so.  That's why it ran the first time, but not thereafter.

By midnight it was put together again (for the third time!).  Crossed
our fingers, hoped for no bent valves, and turned the key.  It ran!  A
little loud (due to new un-pumped lifters) but it ran fine.  BTW I think
that the horrible noise I heard the first time was indeed a chorus of
un-pumped lifters.  And the rapping noise?  Again, an un-pumped lifter.
(It made the same noise when I started it up after changing the oil
later the next day, at least for the second or two that oil was starting
to pump.  Must have been a lifter.)  There was also an additional softer
ticking, which was more like the classic lifter noise.  However the
articles we saw mentioned that that was to be expected for at least
several minutes.

What next?  Why, a test drive of course!  We hopped in the car at 1am
and headed over towards Todd's shop (about a 20-minute drive each way).
Turns out Todd had had the good sense to go home before that, but we had
fun driving the car.  We were prepared to expect a softer low end, but
if anything the butt dyno says that from 2k rpm on up it felt stronger!
My impression is that there was _no_ loss anywhere in the rev range, but
I'll wait for a definitive reading until I get it on a real dyno.  This
is with my old P-chip, mind you, since I didn't have the correct G-chip
yet.

And around 6k rpm, where the stock motor would start running out of
breath, it now continues to pull.  Can't wait to get it on a real dyno!
And at WOT above 4k rpm the motor makes a more urgent, harder-edged
ripping growl than before.  By the time we got back to Tom's house the
ticking had quieted down considerably.  By the next day, it was just
about gone.  After cleaning up, putting away the tools, and packing the
car, it was 2am and I was happy but spent.  No way I was driving to NH
before morning!  A good night's sleep, and I was on the road by 8am
Monday.

The car ran great for the 300 mile trip back (and since then too).  The
only downsides I can see for these cams are (1) a slightly lumpier idle
(it will be fixed by the G-chip, I'm told), and (2) maybe 1 or 2 MPG
less, but that's tough to tell.  And the obsessive-compulsive in my
wonders did I _REALLY_ torque the cam bearing cap nuts and cam sprocket
bolts to the correct values?  Intellectually I know I did, but my brain
is always looking for something unreasonable to worry about.

That's about it.  I'll post my photos as soon as I get 'em sorted out.
I'll also let you know about the dyno results when they're in...

BTW - big thanks to:
- Tom D. (and family) for encouragement, help, support, facilities,
dinners, etc...
- Todd S. for the cams, springs, lengthy phone advice, calling back as
soon as he returned from vacation, etc...
- Mike Potter for the lifters, tools, and advice.
- Arthur for the kind words of encouragement and support.  Not! ;)
- Everyone else for their encouragement.

Cheers,
- Bob T.
  '96 GTI VR6 107k miles.  268s!
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