Crank locking tool / will it work??

[Martin Millers]

Well, from my point of view locking the pulley as the vag tool does, seems to be more conservative. The torque causes stress in a located area, affecting fewer parts.

Locking the pulley avoids stress in the key of the cambelt pulley, caused by the friction between the bolt and the pulley. That is a good point Andy. But friction fades as soon as the bolt starts to move.
Afterthat, the torque goes directly to the crank, and if we are locking the pulley the key will suffer. In the other hand, after some move, torque should decrease.

Using the tool that locks the flywheel is an smart idea
But, means transmiting the full torque through the crank... that should not be a problem, but many parts involved...

I would prefer to lock the pulley, less parts, in a very located area....

[benntenn67]

Lock both, flywheel & pulley ??

[jade]

The key only locates the pulley, when the bolt is torqued correctly that's what holds it in place

[johne]

I think we're missing something here. If we talk about tightening the camshaft bolt - and I know we're on about the crankshaft here but just hold on - Paul @S2central is always reminding us that we must use the Audi tool which locks the camshaft, not the pulley, to tighten and undo the bolt because of the very real danger of shearing the pulley key.

If you follow that logic then it would also be best to lock the crankshaft, not the crankshaft pulley and that makes sense to me given that it's the crankshaft you're tightening the bolt into, not the pulley. I know the pulley is being stressed but it is "free" to turn to relieve that stress since ultimately it's the crankshaft that the bolt tighens into.

So why do Audi use the tool on the pulley? My guess is that because it's easy and saves time when doing the job over removing the starter motor or speed sensors to lock the crank and although the bolt is tight they judge breaking the key isn't an issue.

There is the issue of the tighening torque travelling the length of the crank if you lock the flywheel and I have pondered that myself but I suspect the stresses put through the crank generating 300+ HP far exceed the pulley bolt tighening torque.

As a BTW, when I've done the job on my car, I've locked the flywheel by removing the ECU speed sensors which are easier to get at than the starter motor, I just wish someone would machine a locking tool to bolt on there

John