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Subject: torque settings

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Bob TX    Posted 10-16-2017 at 12:09:09 [URL] [DELETE]        [Reply] [No Email]  
  • torque settings
  • i can not find the torque settings for bolts clutch to flywheel 52 8n
    can some one help thanks

    BlasterStumps    Posted 10-16-2017 at 15:17:27 [URL] [DELETE]        [Reply] [Email]  
  • Re: torque settings
  • Bob just to be sure what you have, would you take a look at the head of the bolts to see what grade they are. If grade 8 for a 5/16" NF, I believe the torque spec is 25 ft lbs. If your torque wrench has a slip of paper with torque specs you could double check me on that.

    Tony    Posted 10-17-2017 at 10:16:29 [URL] [DELETE]        [Reply] [No Email]  
  • Re: torque settings
  • IIRC they are 5/16" (I just had my engine out, I should know for sure but don't).

    Yes 17-24, Use new grade eight bolts and washers, lube the threads and under the head. Gr8 can't hurt, over strength fasteners are never a bad idea.

    THe bolts are subject to occasional shock loading. BUt the machine only produces 23+/- hp so maybe the point of grade eights is moot.

    Bob TX    Posted 10-17-2017 at 12:06:33 [URL] [DELETE]        [Reply] [Email]  
  • Re: torque settings
  • Thanks for the help. So many numbers so little time. Parts book says 5/16-18 shoulder head. Common torque chart says 17 ft-lbs. ford model A car says grade 5 torque 20. could not find any numbers in shop manual FO-4. what book does the 17-24 come from.

    TPD    Posted 10-17-2017 at 18:57:17 [URL] [DELETE]        [Reply] [No Email]  
  • Re: torque settings
  • 5/16-18 Grade 5 torque at 17 Ft/lbs. The 24 number is equivalent value in Newton Meters. Be sure you know which scale your wrench is in and how to convert. My Book shows 5/16-18 Grade 5 at 21 ft/lbs; Grade 8 at 25 ft/lbs. Torque wrenches can have scales of Inch-Ounces/ Inch-Pounds / Foot Pounds / Meter-Kilograms / and/or Newton-Meters. The proper technique for applying torque settings is done in three stages. Take final value and divide by 3. First sequence at low setting, second step at middle setting, final step at desired torque value all going in the same sequence. Here's a chart...

    Tony    Posted 10-17-2017 at 18:55:39 [URL] [DELETE]        [Reply] [No Email]  
  • Re: torque settings
  • DOn't obsess over numbers. Torque of fasteners is determined by the strength of the material of the fastener, the thread profile, number of threads, etc. Torque specs will sometimes be less than the yield strength of the fastener based on design parameter, but never greater. The engineers designing the product determine the desired torque based on load, whether in shear or compression, etc. number of fasteners, etc.

    Example: Look for the torque spec for a 2n water outlet housing. Adding a few ft/lbs torque or degrees of angle "jus cuz it holding the heads, turbo, rods mains" etc is not the answer. It stretches the threads and the fitment will loosen prematurely.

    Put the 5/16-18 bolts with lubed threads in and torque it to 20-25. It will hold.

    You're not replacing the pressure plate on a 475hp 1750 ft/lb torque CAT or 855 Cummins motor.

    Those get new CAT bolts, washers and torqued using the template method.


    TheOldHokie    Posted 10-17-2017 at 19:08:17 [URL] [DELETE]        [Reply] [No Email]  
  • Re: torque settings
  • The reality is torque is a pi$$ poor indirect measure of stress - e.g. clamping force. That is why the industry has a bunch of alternative and more accurate measures/indicators for applications where it is important. The only thing torque is good for in this application is getting enough stress to prevent the bolts from loosening. Simpler solution = "wrist tight" on the head of a 1/2" socket wrench and a good high strength thread locker.


    Tony    Posted 10-17-2017 at 21:09:52 [URL] [DELETE]        [Reply] [No Email]  
  • Re: torque settings
  • Amen.

    Tighten the damn bolts. It's a 60 year 25hp tractor, not the Space Shuttle.

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