Timing Belt: 12V 2.8 (LONG procedure)

[Chris Semple - Force 5 Automotive]

> -----Original Message-----
> From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
> Behalf Of Elliott Potter

> Here ya go; I'm going to post the full procedure to the list for the
> purpose of peer review, and if it's good it's going on my web site
> (12v.org) whenever I get to it.
-----Elliott's excellent writeup condensed for comments here---------

> Tools you'll need/want:
> - 24mm (? I think so) 12-point socket

Yeah, that's the right socket.

> - Audi tool #3242, the crankshaft holding tool.  This is VERY handy.
> You cant rent it at Blau, I think.
> - Audi tool #3243 is also helpful -- the camshaft holding tool.
> Conceivably you could do without this one.

I'm not so sure about that, see my comment below.

> 10-Attach your camshaft holding tool if you have it.  The cams are
> perfectly happy to stay in place as long as you don't put too much
> pressure on them, but it's good to have the tool there.  If the cams do
> slip, it's probably worse for your heart than the engine.
> 12-Remove the camshaft holding tool, and remove the timing belt.
> 19-Loosely thread the timing belt over the camshaft sprockets and under
> the water pump, then re-install the camshaft holding tool.  Now put the
> teeth of the belt into the camshaft sprockets; make sure you get the
> right tension.  If you were doing this the right way, you would have
> loosened the camshaft sprockets to get this tension exactly right.
> We'll assume that it was already good.  If that's not a safe assumption,
> one of our resident list mechanics can correct me here.  Once you've got
> the proper tension around the camshaft sprockets and the water pump,
> thread the belt around the idler pulley, the crankshaft sprocket, and
> the tensioner (last).  Get good tension on the rest of the belt and
> tighten the tensioner pulley.

When I first read through this writeup, I was mentally nodding as I went
down the list, but the cam locking tool bit set off my warning alarm. The
tensioner is offset to the RF side of the engine, effectively tensioning
only that "leg" of the tbelt when you adjust it. The tool allows you to
maintain cam orientation and still loosen the sprockets on the cams that the
belt rides on. This is necessary as they will want to move(freewheel) while
you tension the belt. Tightening the sprockets back down on the cams after
the adjustment keeps everything in order. The sprockets are a taper fit to
the cam, no keyway, and require a puller to free them. It's a bit of a heart
stopping procedure the first time around. I've got a cheesy Sears two jaw
puller that does the job with a sacrificial safety nut on the end, so as not
to mar the cam. It takes a fair bit of pull to loosen a stuck sprocket, and
they come off with a good quality CRACK!

Anyhow, the point being that I don't think you can get an accurate belt
tension with having the cam sprockets loosened to freewheel, and the locking
tool in place to keep the cams TDC'd. YMMV

-Cheers
Chris Semple
Concord NH
   '98 A4q 30v
        etc