Let's talk a little torque tech?????????????/
#1145555
12/28/11 12:07 AM
12/28/11 12:07 AM
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Joined: Jan 2003
Posts: 1,235 TN
65racer
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2009 IHRA World Champion
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2009 IHRA World Champion
Joined: Jan 2003
Posts: 1,235
TN
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Was wondering how many of you guy's figure out the torque of a bolt, or stud,when you are using an extension on your torque wrenches?
I am in the process of freshening my engine, and ready to torque the heads, and was figuring out the torque when using an extension on the wrench the studs call for 80 lbs, but when you figure it out with an extemsion on the tw the torque valus is quite a bit less, I am figuring it this way
length of torque wrench multiplied by the stated torque of stud
20" x 80 lbs
Now add a 4" extension on for clearance over the rocker stands, add the 4" to the length of the torque wrench
20" + 4"
Now take the totals of the 2 and divide them,
20x80= 1600 20+4= 24 devide the 24 into the 1600
Now you have 67lbs average for the torque of the studs this seems like it is low to me, am I over thinking this or not, I have had a problem for the last few seasons with head gaskets showing leaks when the engine comes down for the winter freshening, and was trying to figure out the root cause of the problem, I feel like they are not getting torqued enought to seal them. by the way I am using the steel shim gasket, have tried every trick I know to tweak them to get a seal, and have not been successful yet sooooooooooooo how to you do your torquing, when you do heads??????
Thanks Dave
Last edited by 65racer; 12/28/11 12:37 AM.
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Re: Let's talk a little torque tedh?????????????/
[Re: ahy]
#1145559
12/28/11 12:30 AM
12/28/11 12:30 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Master
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Romeo MI
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Quote:
An extension added to the socket will wind up a little but it won't change the torque. Torque is the same at both ends of the extension.
That said, a "click" type wrench does have some dynamics... if you "click it fast" with an extension, torque may be affected - up or down. With a beam style wrench, no impact of the extension at all. For head or other critical fasteners an inherently accurate beam style wrench is better.
I agree on the extension ... its all under the same load... I always move things at one rate as to not upset the torque
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Re: Let's talk a little torque tedh?????????????/
[Re: 65racer]
#1145560
12/28/11 12:34 AM
12/28/11 12:34 AM
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Joined: Jan 2005
Posts: 3,699 Newport, Mi
Evil Spirit
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A torque wrench measures the twist sent down into the fastener - the length of the handle only changes the amount of force needed to obtain that twist. So to apply 100FT/LBs of torque (twist) you would need to apply 100LBs at 12", 75LBs at 18" and 50LBs at 24". As to the extension absorbing torque - that would depend on the length and quality of the extension - a short tool truck (Snap On, Mac, Matco) would deflect less than a longer box store (Home Depot, Ace) extension. I don't know of a formula to figure that out - it would depend as I said on the perticular extension used.
Free advice and worth every penny... Factory trained Slinky rewinder.........
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Re: Let's talk a little torque tech?????????????/
[Re: jamesc]
#1145563
12/28/11 02:24 AM
12/28/11 02:24 AM
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Posts: 3,699 Newport, Mi
Evil Spirit
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Quote:
adding an extension should not affect the final torque assuming the fastener is being tightened properly in the first place. the length of a wrench would affect the torque but being you're using a torque wrench that is not a consideration.
Again - the length of the wrench does not affect the torque , it only affects the force you have to apply to the wrench to obtain the torque. Torque is being measured at the point of rotation, not where the force is being applied. Take a 2' bar - it does not matter if you apply force at anywhere on the bar or at what angle (3, 6, 9, 12 o'clock) 100FT/LBs of TORQUE is the same, only the force to obtain it changes with distance from pivot point.
Free advice and worth every penny... Factory trained Slinky rewinder.........
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Re: Let's talk a little torque tech?????????????/
[Re: Evil Spirit]
#1145564
12/28/11 02:33 AM
12/28/11 02:33 AM
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Posts: 5,875 communist bloc of new jersey
jamesc
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Quote:
Again - the length of the wrench does not affect the torque
i was referring to a standard wrench with a given applied force. in this case the length of the wrench DOES matter which was the point i was trying to make. for a given applied force the longer the wrench the greater the applied torque. you put five pounds on the end of a 12" wrench you get five pound feet of torque, you put the same five pounds on the end of a 24" wrench you get 10 pound feet of torque.
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Re: Let's talk a little torque tech?????????????/
[Re: jamesc]
#1145566
12/28/11 02:46 AM
12/28/11 02:46 AM
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MR_P_BODY
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I have seen some people(not many) that would hold the extension during the torque process and I told them not to hold there and explained that they were changing the value by what ever they were holding in their hand... hold the wrench at the pivot and the end... I do like the clicker style.. just makes the job go quicker....... just make sure they are accurate
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Re: Let's talk a little torque tech?????????????/
[Re: Evil Spirit]
#1145567
12/28/11 03:00 AM
12/28/11 03:00 AM
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Posts: 5,875 communist bloc of new jersey
jamesc
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Quote:
The bolt really doesn't care where you place your hand to turn it, only how hard you turn it. You don't measure torque at the handle of the wrench, that is applied force . Torque is measured at the socket end, as a measurement of rotational force.
i never said you measured torque at the handle (though in reality you do) but given the amount of applied force and length of the handle you can calculate the amount of torque applied this is why torque is given in POUND FEET a measure of force AND a measure of LENGTH. torque is a measure of a turning force but the value assigned to it is a measure of length and force. my point was that the longer the wrench if you apply the same force the torque will be greater. i was trying to give a little explanation of the law of the lever. i may not be a theoretical physicist but i do have a little smarts you know.
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Re: Let's talk a little torque tech?????????????/
[Re: Evil Spirit]
#1145573
12/28/11 04:01 AM
12/28/11 04:01 AM
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And back to the second part of the question, about the extension changing torque - here's some food for thought. I have a 30" extension for trans bolt removal - I'm pretty sure it's a Snap-on, so it's a quality tool. There is a lot of times that I've had this extension twist 1/8 - 1/4 turn and need over 100FT/LBs to break loose a 3/8 bolt. Common sense tells you that you will twist the head off a 3/8 trans bolt LONG before 100FT/LB's. Where's all the extra torque going? It's being absorbed by the extension. So I just went out to the garage and did a little experiment. I put a 3/8 nut in the vise, tossed a couple washers on a grade 8 3/8NC bolt and using my click torque wrench set to 75LBS and using the 30" extension, tightened the bolt. There was over 1/8 turn of twist in the extension. Removed extension and started setting the torque wrench at 35, 40, 45 etc till the bolt started tightening again. It was good at 50, but started to move at 55, telling me that the extension absorbed about 20 FT/LBs torque. Granted, the 30" extension is an extreme case, but I would have to say if the extension is being twisted hard enough to deflect it is absorbing torque.
Free advice and worth every penny... Factory trained Slinky rewinder.........
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