Crank bolt torque for timing belt change (10v)

[Michael G. Loeks]

> Date: Mon, 01 Dec 2003 08:16:20 -0500
> From: Kneale Brownson <knotnook at traverse.com>
> Subject: Re: Crank bolt torque for timing belt change (10v)
> To: antar at comcast.net, quattro at audifans.com
> Message-ID: <4.1.20031201081221.017add20 at pop.traverse.net>
> Content-Type: text/plain; charset="us-ascii"
> 
> I thought a torque wrench applied a measured amount of torque TO THE
> SQUARE
> DRIVE PART of its assembly????
> 
> If you put a 258 ft. lb. torque setting on a torque wrench five feet
> long
> or one foot long and make it click, you've applied 258 ft. lb. of
> torque to
> the square drive fixture.  The Audi tool is designed so that when you
> supply the desired torque to the hole in its end, you've applied the
> correct torque to the nut on the crankshaft.
> 
I do not agree.
For practical purposes it doesn't make enough difference to specify the 
length of the torque wrench. Any torque wrench that is capable of 
delivering that amount of torque would have to be of a certain length to 
be manageable. However, the torque would vary dramatically if a 1 ft 
wrench were used vs. a 5 ft wrench. Think of it like this:
Assuming a 1ft long SST with 258ft-lb delivered at the end of the torque 
wrench,  
1ft torque wrench = 258lb on end X 2ft = 516ft-lb at bolt.
4ft torque wrench = 64.5lb on end X 5ft = 322ft-lb at bolt.
5ft torque wrench = 51.6lb on end X 6ft = 309.6ft-lb at bolt.
So the final torque is dependent on the length of the torque wrench since 
the SST is a constant. The longer the torque wrench is, the less 
significant the SST becomes. It would also appear that error could be 
introduced depending on where the torque wrench were held.
  I personally use the cheater pipe on the breaker bar method.
Mike