I believe the 2.7T is set up the same as the 2.8 engine in the A4. In this car (which I own), to do the timing service, cylinder #3 needs to be at TDC on the compression stroke - it's the key cylinder, rather than #1. This is the rear cylinder on the passenger bank. Looking from above, with the nose of the car at the bottom, the arrangement is:
On the 2.8 (again, I am about 95% sure the 2.7T is the same), there are ovoid-shaped brackets witht different-sized holes in them on the exhaust cam pulleys, meant for mounting a cam locking tool (which is unnecessary). When the engine is rotated so that those brackets are horizontal, with the larger holes to the inside, and the smaller holes to the outside, you are at TDC on cylinder #3.
It's almost academic though - as I found when doing timing belt jobs on the 2.8, the cam lock tool is unneeded, since the cams will not spin when the belt comes off, and there are no indexing marks on the timing belt itself - all the positioning that you need to do is to rotate the engine (use a 24mm socket on the crank bolt), so that the oval exhaust cam brackets are horizontal with the larger of the two holes in each positioned toward the center of the engine. From there, you're good to go.
As a side note, when you put it back together, put the timing tensioner on first, then loop the timing belt over the crank sprocket, up over the idler, and over the driver's side cam first, holding tension on the belt and pulling it tight as you do so. Then go under the large center top pulley, around the passenger exhaust cam sprocket (again, pulling tightly so you don't end up with slack in the belt), and then you'll be able to slide it up over the tensioner (someone needs to be pulling the tensioner so that it allows a little play in the belt as it goes on - once the belt is in place, release the tensioner and it'll snug the belt perfectly).
When it's on fully, note the position of the exhaust cam brackets, and rotate the engine with the socket on the crank, two full rotations. Make sure you don't have any background noise (ie, radio, talking people, etc) while you do this. This will rotate the cams once, and you can stop when the brackets reach the position they were in intially. What you're doing is taking the engine through one full revolution by hand, listening for any valve-piston clearance problems. If you don't hear anything make contact inside the engine when you do this, then you're in good shape to put the car back together again.
Oct 24, 2008 |
2000 Audi A6