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Joined: Jul 2005
Posts: 198
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Jul 2005
Posts: 198 |
Any suggestions for tightening the original 11/16th bolts on my flywheel. I think the bolts are plain steel (no lines on the head to indicate they are case hardened). The Filling Station recommends 131 lbs for a 5/8th plain steel bolt and 228lbs for a 3/4 plain steele bolt. Since they are the original bolts, I don't want to overtighten and snap them off so I plan to replace them with case hardened bolts which would put the torque specs at 196 to 340. That seems high. Would 150lbs suffice for new case hardened bolts? The last thing I want is for the flywheel to break loose.
Jolo
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
Hi jolo, I sure hope I am reading your torque figures wrong. I would think those values would twist the bolt off.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Jul 2005
Posts: 198
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Jul 2005
Posts: 198 |
Ray, that is what I thought. I think 80lbs should be sufficient. Would you agree?
Jolo
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Joined: Dec 2007
Posts: 4,024 Likes: 99
ChatMaster - 4,000
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ChatMaster - 4,000
Joined: Dec 2007
Posts: 4,024 Likes: 99 |
The torque tables are based on the bolt body diameter, not the head size. For example 1/2" bolt typically has a 3/4" hex head.
Also, you need to consider the strength of the threaded hole. Just because you put a Grade 5 bolt in a tapped hole in casting does not mean you can toque it to Grade 5 specs and not damage anything. In some cases the extra tension due to the higher torque will damage the mating parts due to too much compression. Or the parts will distort and not fit together correctly. Or you will strip the threads in the hole.
Rusty
VCCA #44680
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