I am drilling and tapping my 6.9 diesel block head fasteners from 7/16" to 9/16".
Ive done some testing on a spare block and its been successful (Several holes at 250+ lb.ft on the stud with a torque wrench, as high as the wrench will go), but I have some worries about one or two particular holes. They are really close to the back of the block, and After drilling for the 9/16" thread, may only have an 1/8" of wall thickness from the tangent of the hole to the back of the block.
I cant imagine any of the other bosses are any thicker on the other holes, but what is the safe zone for wall thickness on a cast iron boss assuming a top quality grade of cast iron? (These blocks are a very good grade)
Justin
Ive done some testing on a spare block and its been successful (Several holes at 250+ lb.ft on the stud with a torque wrench, as high as the wrench will go), but I have some worries about one or two particular holes. They are really close to the back of the block, and After drilling for the 9/16" thread, may only have an 1/8" of wall thickness from the tangent of the hole to the back of the block.
I cant imagine any of the other bosses are any thicker on the other holes, but what is the safe zone for wall thickness on a cast iron boss assuming a top quality grade of cast iron? (These blocks are a very good grade)
Justin
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