Rod bolts - a few questions and discussions |
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Rod bolts - a few questions and discussions |
ahdoman |
Sep 21 2009, 03:40 PM
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#1
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It's phonetic...Ah-D-O-Man (Audioman) Group: Members Posts: 667 Joined: 7-November 05 From: Santa Clarita, Ca. Member No.: 5,084 Region Association: Southern California |
According to the experts it's imperative to replace the rod bolts when rebuilding. I've read the reason is because when they are torqued originally they stretch? Are they manufactured specifically to do that? If so, why wouldn't that make them weak? If reused why is that any different from reusing other bolts or parts under high torque? What's the science and logic behind this?
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brp986s |
Sep 21 2009, 10:22 PM
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#2
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Member Group: Members Posts: 434 Joined: 27-September 07 From: los angeles Member No.: 8,167 |
ARP is up in ventura. I went up there and bought one their stretch gauges and picked up a catalog, which I think is downloadable that answers your questions. My recollection is that when a bolt is torqued the tension initially ramps up rapidly, but then that rate fades as the bolt stretches. When the proper tension is attained, the bolt stretches, but is not deformed, and static tension is much higherr than cyclic variation the bolt would see when the engine is running. If the reverse were true, the cyclic loading would fatigue and break the bolt.
If you buy a set of their bolts, you'll be impressed with the quality - this ain't flaps hardware. No connection. |
76-914 |
Sep 25 2009, 09:46 PM
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#3
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,513 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
ARP is up in ventura. I went up there and bought one their stretch gauges and picked up a catalog, which I think is downloadable that answers your questions. My recollection is that when a bolt is torqued the tension initially ramps up rapidly, but then that rate fades as the bolt stretches. When the proper tension is attained, the bolt stretches, but is not deformed, and static tension is much higherr than cyclic variation the bolt would see when the engine is running. If the reverse were true, the cyclic loading would fatigue and break the bolt. If you buy a set of their bolts, you'll be impressed with the quality - this ain't flaps hardware. No connection. So someone tell me about this stretch gauge. How is it used? To check old bolts? Or is it an alternate way to measure the tightening. Just curious. |
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