How much torque?
Postmaster
Joined: Jun 2005
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Posting Guru
Joined: Mar 2006
Posts: 1,118
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From: Williamson, NY
I have always wondered why Ford has such wide torque specs like the 85-100 ft-lbs listed above. I always tend to set my Torque wrench to the high side of the range just to be on the safe side. I like things a little more black and white when it comes to torque specs, like "torque the bolts to 95ft-lbs." Any thoughts on this topic?
Post Fiend
Joined: Apr 2004
Posts: 6,473
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From: Lafayette, IN
The reason for that is because torquing bolts to a specific number is actually very difficult due to a number of variables, and generally not necessary. My BIL used to work for Cummins as a Mechanical Engineer, and they did a lot of studying on torque and found that torque + angle gave a more consistant result due to the frictional forces involved. In other words, something like 60 ft-lbs + 90 degrees gave a more consistant "tightness" than 90 ft-lbs. This is due to the physics of the difference between the coefficients of static vs. kinetic friction. 90 ft-lbs on a bolt that is still turning is not the same as 90 ft-lbs on a bolt that is not turning. That is why torque instructions (should) always include the statement that the torque is done while the bolt is turning.
You can also calibrate your torque wrench all you want, but even the slightest amount of grit, oil, grease, water, etc. in the threads will affect the amount of torque you have to apply to get the bolt to the correct "tightness".
Jason
You can also calibrate your torque wrench all you want, but even the slightest amount of grit, oil, grease, water, etc. in the threads will affect the amount of torque you have to apply to get the bolt to the correct "tightness".
Jason
Postmaster
Joined: Jun 2005
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Originally Posted by cujo8
I have always wondered why Ford has such wide torque specs like the 85-100 ft-lbs listed above. I always tend to set my Torque wrench to the high side of the range just to be on the safe side. I like things a little more black and white when it comes to torque specs, like "torque the bolts to 95ft-lbs." Any thoughts on this topic?
In the link I posted they say 85 foot pounds...I was guessing 85 to 100....anywhere around that and you will be ok.
