[Geo]

When a service manual gives torque limits for some bolt tightening, it must be for new parts with new bolts.

When you go by there torque range, let's say -- 70 to 90, what number would you set your torque wrench for?

Now, if the parts and bolts have been used before, what number would you set your torque wrench for?

And, if the bolts are not dry, but oily, would that change the torque?

And, if you are using an old torque wrench, with a lot of use, the torque setting you put it on may not be what it gives you.

[Print Dad]

Hello Geo,
You may be little confused on torque settings.
First if a book says a torque range, they are saying that is what you should torque to.
It does not indicate the breaking point of the bolt.
Bolts are made to withstand certain amounts of force before they snap.
The number of lines on a head of a bolt indicates bolt strength.

But if you are asking what to torque a
Harmonic damper bolt to - the answer would be between 70-90 foot pound of torque.

Also if you are torquing an intake manifold or cylinder head where there are several bolts involved, it is recommended you take the part down to final torque in 3 steps.

If you want an intake manifold torqued to 23-25 ft-lbs

You would follow a sequence or order in which to tighten the bolts.
You would do all the bolts to say 15 pounds. Then you would go back over the sequence and adjust to 19 pounds. Then your final setting would be 23-25 ft-lbs.

In that case, I would set my wrench to 24 ft/pounds.

So to recap - - torque specs for a motor are what the manufacturers want the part tightened to. The age of the bolt should not matter unless there was a lot of heat like on an exhaust manifold. This would weaken the bolt and it could snap long before the intended breaking point.

Bolts are made for different strength uses and therefor you should use the correct bolt for the correct application. You wouldn't want to try to torque a plastic bolt to 50ft/pounds. Of course it would break.

I hope this helps. Trust your tools...trust your eyes and set to recommended settings. Print Dad

[Dave]

Also, I believe the torque settings are for an oiled bolt. There can be up to a difference of 20% in actual clamping force between a dry bolt and an oiled one, even though they both were torqued to the same spec.
Dave

[Geo]

Sam, what I was asking about the range given to torque a certain part, say in the example for the balancer, would you set your torque wrench at 70 or 90, or would you set it at mid-range of 80? I'm curious what most professional mechanics would do.

[Geo]

Dave, I don't think the torque ranges given are for oiled bolts. Who can we contact in the industry that would let us know? I agree with you about oiled bolts - to what percentage I don't know.

[cindys_sn95]

the specs in repair manual with bolts oiled is correct. if it says 90 then set torque wrench to 90.