Author Topic: Help with torque Spec.  (Read 2079 times)

johnhbd

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Help with torque Spec.
« on: March 28, 2004, 06:44:27 PM »
I need help from some of the engine building  guru?s that I have been reading about on this web site. I have looked at all the pictures and corresponding literature and I am impressed.
 I am reassembling engine and need help with the torque spec. for  the nut that holds the counter balance shaft gear to the crankshaft. The service manual calls for 87 lb ft of torque. The tool they show to use is about two inches from the center of the bolt therefore changing the value. By my calculation that would make the actual torque value 99 lb ft.  Any guidance would bee appreciated.
John

dhjunkie

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Help with torque Spec.
« Reply #1 on: March 28, 2004, 06:56:53 PM »
If it is like all OEM tools the special socket will be a long one and the correct torque value will be what it says.   But if you are going to use a regular socket and a 2" extention then you will have to calculate for the deflection of that extention.

johnhbd

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Help with torque Spec.
« Reply #2 on: March 28, 2004, 07:12:00 PM »
The picture in my factory sevice manuel shows the OEM tool has a 2" offset, it is not a deep socket. I have made my own tool but has a 3" offset. This is why it is important to know the actual value.

PilotHawK

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Help with torque Spec.
« Reply #3 on: March 28, 2004, 07:53:49 PM »
if you use the tool at a 90 degree angle to the torque wrench the torque value does not change from the setting on the wrench. However if you use the tool in line with the torque wrench the actual torque will be higher than that read on the wrench. So if you can position the tool 90 degrees from the wrench and you'll be OK. BTW I learned that in helicopter mechanics school, where EVERY fastener has a torque and most have safety wire! An not all of them are easy to get to either :)

johnhbd

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Help with torque Spec.
« Reply #4 on: March 28, 2004, 09:54:52 PM »
Thanks PilotHawk, but I also learned how to calculate the torque values from Pratt & Whitney maintenance manual.(spelled it correct this time)This is how I came to the conclusion of 99 lb ft.

ludedude

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Help with torque Spec.
« Reply #5 on: March 29, 2004, 12:15:59 AM »
You work for P&W? I work for PWC up here in Nova Scotia, Canada. Cool!

johnhbd

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Help with torque Spec.
« Reply #6 on: March 29, 2004, 05:53:12 PM »
Sorry ludedude,it is my son who works as a A&P mechanic for a private charter airline. The manual I used is from P&W of Canada. What  torque value did you use when you re-built the lower end? Do you have the correct tool,if so, does it have a 2" off-set.

ludedude

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Help with torque Spec.
« Reply #7 on: March 29, 2004, 09:45:43 PM »
No sorry, I used Big Tom's method...as tight as you can  :)