Torque Spec: Crank S Bolt
Kenneth Keith
auditude at gmail.com
Thu Jan 26 15:32:50 EST 2006
L DC <ldc007usa at yahoo.com>
>
> According to the Bentley manual, the torque spec for
> the 27mm crank shaft pulley bolt on my '87 VW Quantum
> Syncro, which shares the same drive train as the Audi
> 4KQ, is set at 258 lbs USING tool 2079 (extension
> bar).
>
> This means that in the absence of such tool, the
> torque on the actual 27mm bolt is greater, correct?
Hi Louis,
I don't know if I would phrase it quite that way, but yes the applied
torque on the crank bolt is greater than what you show on the torque
wrench when you use the
2079. If you had the torque wrench directly on the crank bolt without
the tool and correctly torqued it, you would be reading higher ft/lbs
on the wrench than the 258 ft/lbs. The lever effect is multiplying
the applied torque, presumably because of what you wrote next:
> 258 lbs of torque is alot of torque to begin with and
> most torque wrenches I have come across in the Auto
> parts stores max out at 200 lbs.
I think the 200 ft/lb limit of most commonly available (there are
higher ones out there) torque wrenches (say 1/2" drive ones), is the
reason for the factory tool being designed. With the tool you can use
a common torque wrench, and the Audi dealerships don't have to keep
narrowly useful huge torque wrench around just for timing belt jobs.
> I have not asked at any of the stores I've visited for
> higher torque wrenches. Would they carry any of them?
I don't know if I would have a use for a torque wrench that went
higher than 200 ft/lbs. A quality one would certainly be expensive.
It might be a better choice to use a 200 ft/lb one and the 2079.
Another alternative is to get the crank bolt as tight as you possibly
can, because I believe the correct torque on that bolt is really high.
I also haven't heard of anyone putting too much torque on one.
Hth,
Ken
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