Rods
12-17-2015 | 08:19 PM
#171
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Joined: Jun 2012
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From: OK CIty, OK
Mild, think about this- your e-bay rod's spot face isn't flat but you don't know that, so you torque it to 100# once. Well guess what now the spot face is flat and normal to the bolt axis, luckily the cap material was India finest bubblegum. But hey! You torqued that SOB!
Did you introduce any preload? Nope. You're hosed and won't know until it's too late.
EDIT- we were typing similar cases at the same time. Torque lies.
Did you introduce any preload? Nope. You're hosed and won't know until it's too late.
EDIT- we were typing similar cases at the same time. Torque lies.
12-17-2015 | 08:25 PM
#172
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From: OK CIty, OK
Think about this. Earlier we got 160,000psi stress in 0.0055". That equates to some torque, say 120 ft/lb. If the spot face deforms .001, and the cap/rod crush a .001 during our 120# torque we've only imparted .0035 elongation - 45% less
But hey! the torque wrench read the same!
Can anyone tell that I like fasteners?
But hey! the torque wrench read the same!
Can anyone tell that I like fasteners?
12-17-2015 | 08:38 PM
#173
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Posts: 11,332
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From: chicago
Very true. I recently rigged up a dial indicator on a poly lock with hardware in place (rocker, spring, pushrod, etc). Just rolling the engine over by hand, I had about .002 of stud deflection while valve went thru its lift cycle. With just my thumb pushing against the polylock, I was able to get about .004 deflection.
12-17-2015 | 10:33 PM
#176
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I guess most of the diy guys are just getting lucky because there sure isn't that much talk about tips failures from bolts.hydrolocking and reversion,yes,but cycling rods bolts.no way
And I've seen and done a ton of Builds that don't do that.everything from cheap stockers,eagle's to Oliver and full out drag race aluminum rods(and these guys go to 9600rpm).
The lube on the threads and back side are more critical as well as stretch if that's the process you are going to use.
And I've seen and done a ton of Builds that don't do that.everything from cheap stockers,eagle's to Oliver and full out drag race aluminum rods(and these guys go to 9600rpm).
The lube on the threads and back side are more critical as well as stretch if that's the process you are going to use.
12-18-2015 | 07:15 AM
#178
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I know I'm being a dick but.....................Just to be a technically correct those fastners you're all talking about are called screws not bolts. A screw goes into a threaded hole in the mating part, a bolt is secured with a nut.
and
I'd still be equally concerned with bad threads in the rod causing a issue vs the screw.
and
I'd still be equally concerned with bad threads in the rod causing a issue vs the screw.
12-18-2015 | 07:28 AM
#179
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If any of you are really interested in learning about fasteners, there is a book that is my Bible on this stuff and it's written by a guy named Carroll Smith, called Nuts, Bolts, Fasteners and Plumbing. If any of you have an ARP catalog, you'll see a tribute to John Carroll Smith somewhere in the beginning. He was one of the early contributing engineers at ARP and worked throughout the racing industry. This book is a great read for anyone interested in this sort of thing. It's out of publication but I'm sure you can find copies on EBay and such.
12-18-2015 | 07:32 AM
#180
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Joined: May 2012
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From: Midwest & T-Rock
Very true. I recently rigged up a dial indicator on a poly lock with hardware in place (rocker, spring, pushrod, etc). Just rolling the engine over by hand, I had about .002 of stud deflection while valve went thru its lift cycle. With just my thumb pushing against the polylock, I was able to get about .004 deflection.
