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SVT Shelby GT500
Fourcam, check out this thread about the 5.4
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<blockquote data-quote="Fourcam330" data-source="post: 3535456" data-attributes="member: 24445"><p>As far as the first link is concerned, I believe RobertLane stated that the GT500 was using 4340 forged Manley H beams, which is incorrect. We already know they're from Mahle and not as good.</p><p>Regarding the crank issue... Is it possible that due to the huge load on the front of the crank from the blower/26lb damper, that the forged cranks are actually snapping? Yes. I received some info on this issue around a month ago though I wasn't sure what was actually causing the problem at that time. </p><p>You can also see this kind of problem with forged 4.6 cranks in cog driven supercharged applications. Simply too much load on the snout of the crank. </p><p>My best guess as to how to resolve the issue (going by what's in front of me) is by using a large diameter ATI dampner (~$400) which would definitely reduce weight on the snout but dampen harmonics just as well or better than the stock piece. </p><p>Forged 5.4 cranks are stout pieces, essentially mimicing forged 4.6 cranks, save the lack of a center counterweight (which doesn't really come into play harmonically speaking until over 7500rpm). Stock forged 5.4 cranks have been tested to 7500rpm/1400HP before showing signs of flex. </p><p>That being said you also have to remember the Ford GT crank issue (same crank). The oil leak that required a speed sleeve to fix (TSB) was due to a random worker who incorrectly polished the cranks with an emory cloth--instead of keeping his hand in the same place while the crank revolved, he moved it down the length in effect creating a path for the oil to follow out of the engine.</p></blockquote><p></p>
[QUOTE="Fourcam330, post: 3535456, member: 24445"] As far as the first link is concerned, I believe RobertLane stated that the GT500 was using 4340 forged Manley H beams, which is incorrect. We already know they're from Mahle and not as good. Regarding the crank issue... Is it possible that due to the huge load on the front of the crank from the blower/26lb damper, that the forged cranks are actually snapping? Yes. I received some info on this issue around a month ago though I wasn't sure what was actually causing the problem at that time. You can also see this kind of problem with forged 4.6 cranks in cog driven supercharged applications. Simply too much load on the snout of the crank. My best guess as to how to resolve the issue (going by what's in front of me) is by using a large diameter ATI dampner (~$400) which would definitely reduce weight on the snout but dampen harmonics just as well or better than the stock piece. Forged 5.4 cranks are stout pieces, essentially mimicing forged 4.6 cranks, save the lack of a center counterweight (which doesn't really come into play harmonically speaking until over 7500rpm). Stock forged 5.4 cranks have been tested to 7500rpm/1400HP before showing signs of flex. That being said you also have to remember the Ford GT crank issue (same crank). The oil leak that required a speed sleeve to fix (TSB) was due to a random worker who incorrectly polished the cranks with an emory cloth--instead of keeping his hand in the same place while the crank revolved, he moved it down the length in effect creating a path for the oil to follow out of the engine. [/QUOTE]
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SVT Shelby GT500
Fourcam, check out this thread about the 5.4
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