ARP 8740 vs ARP 2000 5/16" connecting rod bolts for H beam Rods, Anyone have any experience with either of these? |
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ARP 8740 vs ARP 2000 5/16" connecting rod bolts for H beam Rods, Anyone have any experience with either of these? |
gothspeed |
Jan 24 2011, 03:07 PM
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#1
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Senior Member Group: Members Posts: 1,539 Joined: 3-February 09 From: SoCal Member No.: 10,019 Region Association: None |
I was reading this old thread;
http://www.914world.com/bbs2/index.php?sho...amp;hl=ARP+8740 about a batch of h-beam rods with ARP 8740 rod bolts. I wanted to get feedback from anyone who used these rods on a hi-performance type 4 application and what were the results? Are the ARP 8740 bolts described for use in this 'batch' H rod a 5/16" or 3/8"? What kind of RPMs were run and how did the 8740 bolts hold up? Here is the ARP description of the two bolt materials; quote: 8740 CHROME MOLY: Until the development of today’s modern alloys chrome moly was popularly considered a high strength material. Now viewed as only moderate strength, 8740 chrome moly is seen as a good tough steel, with adequate fatigue properties for most racing applications, but only if the threads are rolled after heat treatment, as is the standard ARP production practice. Typically chrome moly is classified as a quench and temper steel, that can be heat treated to deliver tensile strengths between 180,000 and 210,000 psi. ARP2000: An exclusive, hybrid-alloy developed to deliver superior strength and better fatigue properties. While 8740 and ARP2000 share similar characteristics—ARP2000 is capable of achieving clamp loads in the 215,000-220,000 psi range. ARP2000 is used widely in short track and drag racing as an up-grade from 8740 chrome moly in both steel and aluminum rods. Stress corrosion and hydrogen embrittlement are typically not a problem, providing care is taken during installation. |
914werke |
Jan 25 2011, 09:06 AM
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#2
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"I got blisters on me fingers" Group: Members Posts: 10,145 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
As I recall Jake pulled the plug on that deal! No rods ever made it into folks hands. (or at least mine)
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Jake Raby |
Jan 25 2011, 08:48 PM
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#3
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
As I recall Jake pulled the plug on that deal! No rods ever made it into folks hands. (or at least mine) AND all money was returned to every single purchaser. I didn't even deposit the checks, I sent them back in the envelopes they ame to us in. That was almost 7 years ago! The manufacturers who were going to make those components did not do as they agreed and were not willing to offer what they had promised. They didn't get a single dollar. 8740 bolts are fine for sane RPM levels and outputs. They are fine unless you miss shifts or have heavy rod beams, wrist pins and pistons with revs less than 6500 RPM. The ARP 2000 is a better bolt and what most all our rods use, or a custom aged ARP 2000 unit, which is what we use in the M96 engines. We also use these in EP/FP 914 race engines, one of which has 2.5 years of 8,500 RPM service under it's belt. But the bolt is only as good as the rod that it couples.. Rods that lack strength allow bolts to loosen, then the bolt fails. Most people reading this don't have an application with the ability to outperform an ARP 2000 bolt- |
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