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Hi,

Anybody knows the length of the Porsche 9110 Special Tool?

I'm trying to replicate it in order to apply the correct torque to the nut which secures the threaded pin to the intermediate flange.

Thanks,

Luis.

post-7054-006396700 1283162598_thumb.jpg

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Do you need the correct length of the tool so that you can get it to :

A ) fit the job at hand?

or

B ) to get the correct torque?

If you are looking at ( B ), then you don't need the tool's length. Although torque by definition is like a "lever arm" where you apply a force from a specific distance away from the axis, this doesn't apply to this "extension" tool from Porsche. If you remember when we learnt in school about the rules of "Moments" or turning force, as long as you apply the torque on the tool, the same amount of torque will be applied to the bolt you are tightening.

So, if you want to apply X lb/ft to the bolt through the special extension tool, you just apply X lb/ft to the tool. It will apply Xlb/ft to the bolt.

Hope this helps.

Hi,

Anybody knows the length of the Porsche 9110 Special Tool?

I'm trying to replicate it in order to apply the correct torque to the nut which secures the threaded pin to the intermediate flange.

Thanks,

Luis.

Edited by 996noob

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Sorry 996 Noob but you are incorrect! When you put an extension on a torque wrench, like a crow foot or a dog bone, the torque applied to the fastener increases, since the lever arm increases.

Here is the formula: M1 = M2 x L1 / L2

Where:

M1 is the torque setting of the wrench.

M2 is the actual torque applied to the nut

L1 is the normal length of the wrench

L2 is the extended length of the wrench (Length of wrench + length of adapter)

Example:

M1=torque wrench setting ?

M2=80 FT-LBS (Desired torque)

L1=18" (Length of torque wrench)

L2=22" (Total length of wrench with 4 inch extension added to wrench)

80x18/22=65.45 M1 therefore = 65.45; In other words if you want to torque a fastener to 80 FT-LBS using an 18 inch torque wrench with a 4 inch torque extender you will set the wrench to 65.45 FT-LBS

  • Upvote 1

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Hi,

Anybody knows the length of the Porsche 9110 Special Tool?

I'm trying to replicate it in order to apply the correct torque to the nut which secures the threaded pin to the intermediate flange.

Thanks,

Luis.

If you know the final torque required at the fastener, couldn't you back calculate the torque wrench setting for any length special tool;s "arm"?

Edited by JFP in PA

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If you know the final torque required at the fastener, couldn't you back calculate the torque wrench setting for any length special tool;s "arm"?

On my manual there's only the torque setting with the special tool, that's why I would like to know the length of the tool.

I've read that overtorque of this nut is one of the causes for the IMS bearing to fail, so I would like to be as precise as possible fastening it...

Thanks,

Luis.

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The manual has:

Lock nut on intermediate shaft flange M8 X1 10.0ft/lb or 8.0ft/lb if special tool 9110 is used.

So I would say 10ft/lb

Edited by rb101
  • Upvote 1

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The manual has:

Lock nut on intermediate shaft flange M8 X1 10.0ft/lb or 8.0ft/lb if special tool 9110 is used.

So I would say 10ft/lb

Mmmmm... we must have not the same manual...

Thanks a lot for the answer!

Cheers,

Luis.

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I 'm not sure if you are completely correct.

The lever arm does not really increase.

It only increases if the extension and your torque wrench are rigid.

Instead, while you are applying X lb/ft to the extension, and the extension is a free body, it will in turn apply X lb/ft to the bolt you want to torque.

If you look at the fundamentals of torque and moments without any preconceptions, you will see what I mean. Remember what we learnt in Physics during university al those years ago, a free body not rigidly attached to anything else, subjected to a turning moment will have the same turning moment ANYWHERE on its body.

So, when you apply the torque by torque wrench to the "extension", it will apply the same torque to the bolt on the other side - because the torque wrench and the "extension" are not rigidly connected.

Think about it.

Furthermore, your formula works only if you are talking about applying a Force.

The unit of Torque comprises of a Force multiplied by a Distance. If you change the Distance, you have to change the Force in order to maintain the same Torque. This is what I think you meant in your explanation. However, I think you might have confused the Force with Torque, because you aren't applying a Force with the Torque wrench, you are applying a Torque, and as such your formula does not apply.

Sorry 996 Noob but you are incorrect! When you put an extension on a torque wrench, like a crow foot or a dog bone, the torque applied to the fastener increases, since the lever arm increases.

Here is the formula: M1 = M2 x L1 / L2

Where:

M1 is the torque setting of the wrench.

M2 is the actual torque applied to the nut

L1 is the normal length of the wrench

L2 is the extended length of the wrench (Length of wrench + length of adapter)

Example:

M1=torque wrench setting ?

M2=80 FT-LBS (Desired torque)

L1=18" (Length of torque wrench)

L2=22" (Total length of wrench with 4 inch extension added to wrench)

80x18/22=65.45 M1 therefore = 65.45; In other words if you want to torque a fastener to 80 FT-LBS using an 18 inch torque wrench with a 4 inch torque extender you will set the wrench to 65.45 FT-LBS

Edited by 996noob

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torque-extension.jpg

The big difference is that the extension shown above does increase the effective length of the torque wrench. As a result, the actual torque applied to the bolt will be higher than the setting on the torque wrench.

The extension shown in the above picture is called a crowfoot extension, which can be handy when trying to torque hard-to-reach bolts. You must, however, use a formula to account for the length of the extension:

wrench setting = desired torque x wrench length / (wrench length + extension length)

For example lets say that the length of the torque wrench is 18 inches, and the length of the extension is 6 inches. The desired torque is 180 ft-lbs.

Wrench setting = 180 x 18 / (18 + 6)

= 180 x 18 / 24

= 135 ft-lbs.

If the torque wrench is set to 135 ft-lbs, the actual torque applied to the bolt will be 180 ft-lbs.

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Looking at the diagram, I would only agree if we are talking about Force applied at different Lengths, not Torque. I'm not sure where the below example was extracted from, but the explanation below seems fundamentally flawed if we are talking about Torque.

Remember, Torque is a twisting moment, not a force.

Let's put this in practical terms.

Let's say you have a 10 inch long torque wrench. In order to exert X lb/ft of Torque on a bolt, you pull at 10 inches away with a Force of Y lbs. Setting the wrench at X lb/ft, it clicks, as expected.

Let's say now you have a 5 inch long torque wrench, with 5 inch extension. In order to exert X lbt/ft of Torque, you pull at 10 inches away from the bolt with a Force Y lbs. The same, cos it's Force multiplied by distance, fundamental definition. Now, do we set the 5 Inch torque wrench at Half of X lbs feet? Before we answer "yes", remember that we are still pulling Y lbs, not less. It would seem counter-intuitive that the shorter torque wrench should be set lower and click at less setting while we pull the same amount.

Extension means increase length, and to get the same torque, less force is needed. Look at the diagram again. It should mean less force is need at a longer distance, not less torque.

Let's take that very same torque wrench in the diagram, without extension. You apply 50 lb/ft, and it reads 50 lb/ft. What if you moved the "fulcrum" of the torque wrench mechanism along any length from left to right. The mechanism will still receive and read out the same 50 lb/ft, regardless of the length from it to the bolt applied.

Likewise, let's take my example about again, 5 inch extension with 5 inch torque wrench. You need to apply 50 lbs/ft on the bolt. Then we set the torque wrench at 25 lbs/ft at the end of the extension. What if the extension were also a torque wrench? It would be set at 50 lbs/ft, cos it's at the bolt, and at the other end we have the other torque wrench at 25 lb/ft. They both click at the same force (theoretically). What if we reversed the ends of the extension (which is also a torque wrench), then the two torque wrenches will be acting on each other at their connection point. But, one is set at 50lb/ft, but the other is set to 25 lb/ft. Doesn't seem right. They won't click together.

My point is that if you had to swap ends of a torque wrench, and still needed to torque down a bolt, and you could only use a twisting motion to do it at the torque wrench head, you would need the same amount of torque - but now the whole wrench handle is an extension.

I'm just asking for us to just think about it awhile, from fundamentals, before just accepting literature like that at face value.

torque-extension.jpg

The big difference is that the extension shown above does increase the effective length of the torque wrench. As a result, the actual torque applied to the bolt will be higher than the setting on the torque wrench.

The extension shown in the above picture is called a crowfoot extension, which can be handy when trying to torque hard-to-reach bolts. You must, however, use a formula to account for the length of the extension:

wrench setting = desired torque x wrench length / (wrench length + extension length)

For example lets say that the length of the torque wrench is 18 inches, and the length of the extension is 6 inches. The desired torque is 180 ft-lbs.

Wrench setting = 180 x 18 / (18 + 6)

= 180 x 18 / 24

= 135 ft-lbs.

If the torque wrench is set to 135 ft-lbs, the actual torque applied to the bolt will be 180 ft-lbs.

Edited by 996noob

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I have been through this "crow's foot conundrum" argument about a dozen times now; if you do not compensate for the change in the length of the lever caused by the additional length of the added extension, you will over torque the fastener.......................and if you do not want to believe me, check with Snap-On and just about anyone else that makes torques measurement devices, all of them say the same thing..............

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ok, I just wanted to bring this up for discussion sake. This thing has been going through my head for almost a decade. While the accepted practice is what has been always advised, it just doesn't gel with what we understand it to be. oh well...

I have been through this "crow's foot conundrum" argument about a dozen times now; if you do not compensate for the change in the length of the lever caused by the additional length of the added extension, you will over torque the fastener.......................and if you do not want to believe me, check with Snap-On and just about anyone else that makes torques measurement devices, all of them say the same thing..............

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