[GR40RCapri]

Hey guys..

I'm having to change out the cam on the 04 TDI jetta...

do i need to go through all the timing belt removal tools/procedure, or just loosen the tensioner and slip the belt off?

when loosening the tensioner, do I have to loosen the center bolt?

thanks!

J

 

[Fluid]

Just loosen the tensioner and slip the belt off. You still have to lock the crank, insert the cam pin, and loosen the cam pulley.

The tensioner's held in place with a single nut which must be lossened.

 

[GR40RCapri]

damn... I was trying to get away with not having to lock the crank...not that it's not hard..just an extra step.

I guess it may move while being tensioned?

I would think if it goes on exactly where it came off it would be ok???

not trying to shortcut, but trying to shortcut.

thanks!

 

[chittychittybangbang]

You'd think that marking the sprockets would work but that messes up camshaft timing (torsion value). That's enough to cause rough idling, other symptoms. The TDI timing belts are designed to rotate the sprockets during tensioning except for the crank which is locked. There are videos in the timing belt article showing how far the cam sprocket will rotate. This is why you can't count the teeth and mark the belt to get accurate timing.

Do enough in the timing belt removal http://www.myturbodiesel.com/1000q/a4/vw-jetta-tdi-timing-belt-change-replacement-bew-engine.htm to loosen the belt. You don't have to remove the motor mount.

Yes, the center nut is what holds the tensioner in place.

 

[GR40RCapri]

ah, gotcha...


so we need to make sure the cam doesn't turn in relation to the crank..

so cam and crank need to stay STATIONARY while the other pulleys take up the slack...

gotcha.

just realized from the pics of the 'toothed' cam slot, i'm 180 off...

nuts....

 

[chittychittybangbang]

Just to clarify, the camshaft stays stationary because of the pin.

The cam sprocket rotates with the timing belt because the 3x 13mm bolts that attach it to the cam pulley underneath are loose. This ensures that the camshaft stays at TDC while you tension the belt. The loose sprockets ensure even tension and when you unlock the cam/crank, that they keep their relationship. If tension isn't even, after you unlock them, they'll move.

 

[GR40RCapri]

with that being said, should the 3 bolts for the cam pulley be tightened BEFORE the retaining pins are removed??

Thanks!

J

 

[chittychittybangbang]

The 3x 13mm bolts on the cam pulley should be loose while the tensioner is tightened to let the sprocket rotate independently of the pulley and camshaft. The pulley has a key on it which locks it to the camshaft. The cam pin and crank lock are in place.

After the tensioner is tightened and its nut tightened, tighten the 3 bolts and remove the crank lock and cam pin. These should all be in the timing belt writeups.

 

[GR40RCapri]

... These should all be in the timing belt writeups.

thanks... i've read it like 5 times, but some of the stuff starts to slip away......:dunno

J