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Best compromise for less than ideal main bearing bolt design?

Was going to be using these formulas: https://www.engineeringtoolbox.com/bolt-stretching-d_1164.html but using the area of the shank for the tensile stress area variable.

Shank diameter is .455-.460"... will calculate based on the lower number. Shank lengths are ~4-9/16" and ~4-1/16" for the long and short ones respectively:View attachment 434790

On an aside, speaking with the ARP engineer last week there was frustration with how difficult it is to cut through certain myths and unfounded knowledge regarding the customers of their products. Basically all performance oriented fasteners in tension joints seeing cyclic loads should be reduced shank as they are much more fatigue resistant. The problem is they cost more to produce--ARP already has to compete with no-name brands offering "high performance" fasteners from China--and customers think the bolts are weaker because the shank is smaller in diameter vs a traditional style bolt. Hence these style bolts aren't seen much unless they are special ordered by customers who actually know their stuff.
Theyll learn when a rod exits the block.
 
The Chinese head I bought for my Ford pickup had iffy looking bolts included .......I was tossing up whether to use the originals again ,but used the Chinese ones for 1/2+1/2+1/2 turn ,nothing broke and a few years later ,its all good...........nearly busted my arthritic joints though.
 
Was going to be using these formulas: https://www.engineeringtoolbox.com/bolt-stretching-d_1164.html but using the area of the shank for the tensile stress area variable.

Shank diameter is .455-.460"... will calculate based on the lower number. Shank lengths are ~4-9/16" and ~4-1/16" for the long and short ones respectively:View attachment 434790

On an aside, speaking with the ARP engineer last week there was frustration with how difficult it is to cut through certain myths and unfounded knowledge regarding the customers of their products. Basically all performance oriented fasteners in tension joints seeing cyclic loads should be reduced shank as they are much more fatigue resistant. The problem is they cost more to produce--ARP already has to compete with no-name brands offering "high performance" fasteners from China--and customers think the bolts are weaker because the shank is smaller in diameter vs a traditional style bolt. Hence these style bolts aren't seen much unless they are special ordered by customers who actually know their stuff.
Whoa. Did you not say that the metric end was 12mm? Looking at the pic above it appears to be considerably larger. Can you check that measurement?
 
Whoa. Did you not say that the metric end was 12mm? Looking at the pic above it appears to be considerably larger. Can you check that measurement?
The original holes and fasteners for the bearing caps are M12. The bedplate kit provided 9/16 fasteners and instructed to drill and tap the M12 holes for 9/16 coarse. Should all be in the first post.
 
The original holes and fasteners for the bearing caps are M12. The bedplate kit provided 9/16 fasteners and instructed to drill and tap the M12 holes for 9/16 coarse. Should all be in the first post.
Somehow I missed that. Thought it was really weird to be 9/16 on one end and 12mm on the other. Makes sense now.
 
After some experimentation it looks like I'll have to have two indicators setup to track stud stretch; one on the end of the stud, and another tracking compression of the bedplate casting under the stud nut (indicator tip positioned right beside the washer under the nut). The value of the latter indicator will be subtracted from the former.

Per my calculations based on a tensile stress area of 0.1626 sqin that is 4.45 long (on the long studs), to get 27,125.25 lb of clamping force 0.0247" of stretch will be required.
 
Thats a lot of stretch .......old diesel engines that used elongation it was typically 005-007 on bolts of a similar size and length............Have you asked the stud maker ?
 








 
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