So I'm just finishing up, (hopefully) a timing belt/waterpump maintainance job. Now when I pulled the lower timing belt cover, I didn't note the rrelation of the notch in the harmonic balance in relation to the arrow on the tbc, as the tbc was covered in grime and I couldn't see the arrow. So I just cranked on the crank bolt until the mark on the cam pulley lined up with the notch on the valve cover that indicates top dead center. I marked a tooth and the block down on that crank pulley too. Slip old belt off, new one on, adjust pulley and tensioner, all while making sure my marks didn't move. But when I slip the timing belt cover on, (all degreased) I see that the notch on the harmonic balancer is about 1/2 inch ahead (clockwise) from the arrow. I'm unsure if I should be concerned or not.

 

Have you already rotated the assembly to check for interference?

Instead of relying on the mark, when I did my timing belt a few days ago I pulled the #1 spark plug and verified TDC with a stick. I confirmed actual TDC with the camshaft mark and went from there.

 

Pulling the spark plug and checking for compression on cylinder one is a good idea. Once compression finished, you know your at TDC. Use a wooden stick, or a piece of plastic.

 

hmm, I haven't checked that way, but I have cranked the engine over with a socket on the crank bolt. And I read somewhere last night that it's real common for the mark on the cam pulley to be a half tooth shy of the mark on the valve cover when the marks on the belt cover/harmonic balancer are spot on. Like I say, I marked everything when I had the old belt on, and it seems to crank without interference.

 

I checked it again just now, and this morning everything looks spot on. Weird. But good news. Maybe I just got too much sun yesterday.

 

Putting a stick in cylinder one is a good option, as long as your on the correct stroke. Being a 4 stroke engine, the piston will come to TDC twice while only firing one of those times. Another good way to check your TDC is a window located on the bell housing. You can view this from looking from the drivers side of the engine compartment. Look down towards the oil filter, there is a small window on the engine/trans axle housing. When you rotate the crank there are 2 small lines that will come around that you can view thru this hole. The first one is a timing mark for the cam sensor. The second mark is your top dead center mark for the crank pos sensor. If you are unsure where the TDC is, line the second line up with the bottom of the peep hole. Double check with a stick down cylinder one. Your done! I picked this trick up from a friend that went to school in Germany to work on Audi. Thought I would share with you all..
Cheers!

 

Great input, much appreciated ^

 

ive foudn that as long as the mark is to the left of the arrow on the crank pully your fine, if its to the right youll be fucked (true story)

 

I've never done the timing job on the 1.8 or 2.8, but became intimately familiar with it during my V8 swap. Do the other engines have the hole for the crank locking pin? Even if you don't have the tool to lock the crank, you can pull the plug to check. Looking though the port on the block, you should see the hole in the crankshaft for the pin to lock into.

On the V engines it is quite simple to see when the camshafts are aligned as the larger holes on the ends of the exhaust cams are pointed directly inward.

I know that some people like to cheat and mark the belt/pulleys and then just line up the marks again, but this can be bad for two reasons.

1. You have not accounted for belt stretch. Over the last 80k miles that the belt you are replacing has been used, you can expect that it has stretched and as such the cam phasing is slightly off. This will not be enough to cause interference, but performance will suffer.
2. The new belt will have differential tensioning. By this I mean that certain sections of belt will have different tension loads than others. This is a sure fire way accelerate the stretching and eventual shredding of the belt. To achieve even tension on the belt Audi designed the cam sprockets with tapered fits. At first glance this seems idiotic to most. What do you mean that the cam sprockets are not keyed directly onto the cams? When doing the TB service, it is important to break the sprockets free from this taper fit so that they may rotate freely. This way then the new belt is tensioned, the cams stay where they should, but the sprockets can move to equalize the tension everywhere on the belt. Once the proper tension has been achieved, then tighten the sprockets once again onto the tapered shafts.