Rod bolt torque

37chief · Mar 13, 2017

My manual doesn't give me any torque specifications for my A/C Model M. What would be a torque I can use for 1/2 inch rod bolts? Also the head has no torque specifications for 1/2 inch nuts. Any suggestions? Stan

Dick L · Mar 14, 2017

My book does not call out the model M but references Allis Chalmers torque on 1/2" engine nuts as 70 foot pounds.

buickanddeere · Mar 14, 2017

Given how critical connecting rods bolts are and the chances that some Bubba in the past has stretched them while guessing instead of using a torque wrench. This would be the time to consider new bolts.
Torque specs for a 1/2" grade 5 bolt would be in the ballpark.

guido · Mar 14, 2017

Hello 37chief,

For 1/2" grade 5 I would use 75#.

For grade 6&7 I would use 85#

For grade 8 I would use 105#

Remember these values are for dry clean threads. If you lube them you need to reduce your final torgue 10%

Guido.

Rod bolt torque

37chief

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Dick L

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buickanddeere

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guido

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