Engine Mechanical problem
2000 Audi S4 Question 6 cyl Four Wheel Drive Manual 75000 miles
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I am in the process of replacing the timing belt and have the Audi factory manual. It instructs you to
Position the engine at TDC
Install locking pin 3242
Remove vibration damper on crankshaft
Remove idler wheel for toothed belt
I am ok up to hear but this part does not make sense
Compress the toothed belt tensioner and insert tool
T40011 and then remove the toothed belt
Insert camshaft clamp 3391 in securing plates of
two camshafts
Slacken both camshaft bolts and remove
approximately 5 turns
TAKE OUT camp 3391
Pull off both camshaft sprockets
Reinstall both camshaft sprockets and the securing
plate and tighten hand tight (so they can
rotate on the taper shaft but not move axially)
Install new toothed belt
Install camshaft clamp 3391
Remove special tool T40011 from tensioner

What is confusing me is that once release the tension on the belt and remove it what is preventing the cam shafts from rotating in relationship to each other and the crank!

I understand that the clamp 3391 will hold the cam sprockets in alignment but they are seated on a tapered shaft ie not keyed.

It seems to me that value springs could very easily move the cams and screw up the timing.

Am I missing something??

My instructions say nothing about loosening the cam gear bolts. I would mark everything (nailpolish, paint pen) with the crank on TDC. Use a cam holding tool between the two cam gears to hold them in time before loosening the timing belt tensioner.If the cams are held together, they wont move out of time from the crank.Unload tensioner and pin it in place, remove the belt and replace it with new, retension and verify all marks are lined up.If the belt runs the water pump, replace it as well or it will leak within 1 month

Jack

I did some more digging and found out that the cam shafts have a "Flat" machined on the end of them and that the cam securing plates have a "D" shape Inside Diameter that fits over the end of the shaft. When the camshaft clamp tool 3391 is used it aligns the cam shaft in the correct orientation with respect to the crank at TDC. According to the Audi Manual you need to lossen the cam sproket retaining bolts and pull them off the tapored shaft in order to ensure that the new belt is tensioned properly prior to the cam sprockets being pressed back onto the tapored shaft. If this is not done they is a possibility that the span of the belt from 12:00 o'cllock on the left sprocket to 12:00 oclock on the right sprocket will be loose. If this occures the value cam will move relative to the crank at TDC when the securing plate is removed.

I can show you some pictures if this does not make sense.

Makes sense in Audis world.....lol every other car uses an auto tensioner to do this. Over engineering to say the least.So what is your question?