JasonS
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How about a short stud/ nut?Who made the original bolts? That tooling could still exist in someones hands.
Possibly a similar bolt for a different application?
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How about a short stud/ nut?Who made the original bolts? That tooling could still exist in someones hands.
Possibly a similar bolt for a different application?
this bolt:If somebody can get me one that is in good condition I will send it off to our manufacturing center for a quote. I work for Fastenal and since it would be an employee purcahse I might get the cost down significantly. I'm not promising anything but I do know what we charge on the markup side on custom items. Just get it to me and I will go from there.
Russ
True, but something made the designer choose the lower grade bolt. A bolted joint analysis could be done to figure torque vs clamp load on the O.E. bolt and the same at a grade 5 or grade 9. My gut tells me they weren't getting enough bolt stretch to maintain clamp load with higher grade bolts or they had fears of yielding threads at the higher torques required to get bolt stretch and maintain clamp with higher grade fasteners... It would be really nice to know if these failures are from stretching during use or from re-using fasteners during the rebuild processes which is just a definate no-no in a joint relying the fastener stretching to maintain clamp. Since once it is stretched, it is stretched.... Then again, I'm just a back yard hillbilly mechanic who wonders about such things.....spoke with my father who is a metalurgist - he confirmed that all 3 grades are about the same - could test a bolt if i had one to give him.
this means that the stock bolts are rather weak (~ grade 2) and even a grade 5 would be a major imporvement in strength. i would be pretty confident in taking a grade 9 bolt with a slim washer and trusting it to outlast a stock bolt, and they are significantly cheaper.
You guys are talking about all different bolts and even different lengths. I am not all that well versed on the multifuel but I have built a couple hundred engines in my years as a mechanic. Has anyone thought about the weight difference of the bolts and the effects of that on the big end of the rod? Any change in weight is going to unbalance the motor, I don't care how big and ugly it is. The end result will be about the same as what you have been getting. BANG!
Rick
Neither are their owners.... Hey, I resemble that remark.Trust me, these things aren't balanced to begin with.
why do engineers ever spec out less than the best possible. cost. what is in there has lasted quite well for the most part. so cost vs life cycle their choice was a success.True, but something made the designer choose the lower grade bolt. A bolted joint analysis could be done to figure torque vs clamp load on the O.E. bolt and the same at a grade 5 or grade 9. My gut tells me they weren't getting enough bolt stretch to maintain clamp load with higher grade bolts or they had fears of yielding threads at the higher torques required to get bolt stretch and maintain clamp with higher grade fasteners... It would be really nice to know if these failures are from stretching during use or from re-using fasteners during the rebuild processes which is just a definate no-no in a joint relying the fastener stretching to maintain clamp. Since once it is stretched, it is stretched.... Then again, I'm just a back yard hillbilly mechanic who wonders about such things.....
I have a hard time believing that anybody would spec grade 2 bolts for a con rod. Doing a quick google search yields this page which suggests that 4140 is grade 8.spoke with my father who is a metalurgist - he confirmed that all 3 grades are about the same - could test a bolt if i had one to give him. this means that the stock bolts are rather weak (~ grade 2) and even a grade 5 would be a major imporvement in strength. i would be pretty confident in taking a grade 9 bolt with a slim washer and trusting it to outlast a stock bolt, and they are significantly cheaper.