Listers,
What are the "best practices"for installing studs for the Main Bearing Caps and for the Head?
I have heard "bottomed out", "bottom out then back of 1/4 turn", "gently tight", "Locktite" (color) and "nothing out of the ordinary".
I would appreciate all learnings.
Thanks in advance,
Sherwood Parker
TC8355
Tempe, AZ, USA
On Mon, Sep 3, 2018 at 7:26 PM laf48@aol.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]Sherwood I have always bottomed them out with a stud remover / replacer or double nuting them. Make sure the hole is clean and dry with a "Q" Tip, NO oil in the hole as the hydrostatic lock will crack the housing. Also if the threads need cleaning use a thread restorer, not a cutting tap. Hope this helps Len Fanelli Abingdon Performance Ltd. -----Original Message----- From: Sherwood Parker sherparker1@msn.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> To: TABC List mg-tabc@yahoogroups.com> Sent: Mon, Sep 3, 2018 2:02 pm Subject: [mg-tabc] Best Practices? Listers, What are the "best practices"for installing studs for the Main Bearing Caps and for the Head? I have heard "bottomed out", "bottom out then back of 1/4 turn", "gently tight", "Locktite" (color) and "nothing out of the ordinary". I would appreciate all learnings. Thanks in advance, Sherwood Parker TC8355 Tempe, AZ, USA
Thread restorers/reformers aka thread chasers are widely available & used in engine shops. See: https://m.autoserviceprofessional.com/article/94859/Thread-chasing-Restoring-male-or-female-fastener-threads. Basically they re-form threads by pressure instead of cutting away thread form mass. Better versions use a hex head to turn & only re-form thread. Using a conventional tap would cut away deformed thread form affecting and diminishing thread s mechanical properties.Always select nuts that = or exceed Class strength of bolt/stud being used. Once nuts or bolts are tightened to point where male & female threads are deformed to an interference fit. As bolts/stud threads stretch to a point close to ult. -Bill HyattSent from my iPhone On Sep 3, 2018, at 4:32 PM, Roger Furneaux roger.46tc@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: hi Len - I'm not sure what a thread restorer for a tapped hole looks like, but the threads are unlikely to be damaged, only full of baked-in oil. A 2nd. -cut tap will clean out this grunge, especially at the bottom. In fact, this should be done with all the other stud holes when rebuilding an engine The most important thing about studs is that no threads should be outside the block. I read in an engineering journal about tests that had been made, and the best result was obtained by having the block slightly counterbored with the diameter of the studs, second best was no counterbore (but chamfered) and worst of all was not fully seated (either because not chamfered or stud bottoming out). Loctite is not needed (the threads will deform on torqing up and lock themselves) and they only need to be finger-tight. When it comes to the nuts it is vital that they are neither under nor 0ver-torqed: by swapping nuts around you can usually get them all just right (63 + or - 2 lbsf. ft.) but if not use the old trick of removing a few thou from the nut (either on a lathe or fine abrasive sheet on a flat surface). Failure to attend to all these details will quite likely lead to failure of the stud itself. oc[b]T[/b]agonally Roger On Mon, Sep 3, 2018 at 7:26 PM laf48@aol.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u] Sherwood I have always bottomed them out with a stud remover / replacer or double nuting them. Make sure the hole is clean and dry with a "Q" Tip, NO oil in the hole as the hydrostatic lock will crack the housing. Also if the threads need cleaning use a thread restorer, not a cutting tap. Hope this helps Len Fanelli Abingdon Performance Ltd. -----Original Message----- From: Sherwood Parker sherparker1@msn.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> To: TABC List mg-tabc@yahoogroups.com> Sent: Mon, Sep 3, 2018 2:02 pm Subject: [mg-tabc] Best Practices? Listers, What are the "best practices"for installing studs for the Main Bearing Caps and for the Head? I have heard "bottomed out", "bottom out then back of 1/4 turn", "gently tight", "Locktite" (color) and "nothing out of the ordinary". I would appreciate all learnings. Thanks in advance, Sherwood Parker TC8355 Tempe, AZ, USAGuys,
-Bill HyattSent from my iPhone Begin forwarded message: Sorry for incomplete first version, finger moved to wrong part of screen & touched SEND prematurely. Guys,Thread restorers/reformers aka thread chasers are widely available & used in engine shops. See: https://m.autoserviceprofessional.com/article/94859/Thread-chasing-Restoring-male-or-female-fastener-threads. Basically they re-form threads by pressure instead of cutting away thread form mass. Better versions use a hex head to turn & only re-form thread. Using a conventional tap would cut away deformed thread form affecting and diminishing thread s mechanical properties.Always select nuts that = or exceed Class strength of bolt/stud being used. Once nuts or bolts are tightened to point where male & female threads are deformed to an interference fit. As bolts/stud threads stretch to a point close to yield strength male threads elongate in tension & female threads compress. This creates an interference fit where cyclic vibration loosening potential becomes virtually nil. -Bill HyattSent from my iPhone On Sep 3, 2018, at 4:32 PM, Roger Furneaux roger.46tc@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: hi Len - I'm not sure what a thread restorer for a tapped hole looks like, but the threads are unlikely to be damaged, only full of baked-in oil. A 2nd. -cut tap will clean out this grunge, especially at the bottom. In fact, this should be done with all the other stud holes when rebuilding an engine The most important thing about studs is that no threads should be outside the block. I read in an engineering journal about tests that had been made, and the best result was obtained by having the block slightly counterbored with the diameter of the studs, second best was no counterbore (but chamfered) and worst of all was not fully seated (either because not chamfered or stud bottoming out). Loctite is not needed (the threads will deform on torqing up and lock themselves) and they only need to be finger-tight. When it comes to the nuts it is vital that they are neither under nor 0ver-torqed: by swapping nuts around you can usually get them all just right (63 + or - 2 lbsf. ft.) but if not use the old trick of removing a few thou from the nut (either on a lathe or fine abrasive sheet on a flat surface). Failure to attend to all these details will quite likely lead to failure of the stud itself. oc[b]T[/b]agonally Roger On Mon, Sep 3, 2018 at 7:26 PM laf48@aol.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u] Sherwood I have always bottomed them out with a stud remover / replacer or double nuting them. Make sure the hole is clean and dry with a "Q" Tip, NO oil in the hole as the hydrostatic lock will crack the housing. Also if the threads need cleaning use a thread restorer, not a cutting tap. Hope this helps Len Fanelli Abingdon Performance Ltd. -----Original Message----- From: Sherwood Parker sherparker1@msn.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> To: TABC List mg-tabc@yahoogroups.com> Sent: Mon, Sep 3, 2018 2:02 pm Subject: [mg-tabc] Best Practices? Listers, What are the "best practices"for installing studs for the Main Bearing Caps and for the Head? I have heard "bottomed out", "bottom out then back of 1/4 turn", "gently tight", "Locktite" (color) and "nothing out of the ordinary". I would appreciate all learnings. Thanks in advance, Sherwood Parker TC8355 Tempe, AZ, USA[b]From:[/b] Bill Hyatt usaj24@earthlink.net> [b]Date:[/b] September 3, 2018 at 6:33:41 PM EDT [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [b]Fwd: [mg-tabc] Best Practices?[/b]
-Bill Hyatt Sent from my iPhone Begin forwarded message: Sorry for incomplete first version, finger moved to wrong part of screen & touched SEND prematurely. Guys, Thread restorers/reformers aka thread chasers are widely available & used in engine shops. See: https://m.autoserviceprofessional.com/article/94859/Thread-chasing-Restoring-male-or-female-fastener-threads. Basically they re-form threads by pressure instead of cutting away thread form mass. Better versions use a hex head to turn & only re-form thread. Using a conventional tap would cut away deformed thread form affecting and diminishing thread s mechanical properties. Always select nuts that = or exceed Class strength of bolt/stud being used. Once nuts or bolts are tightened to point where male & female threads are deformed to an interference fit. As bolts/stud threads stretch to a point close to yield strength male threads elongate in tension & female threads compress. This creates an interference fit where cyclic vibration loosening potential becomes virtually nil. -Bill Hyatt Sent from my iPhone On Sep 3, 2018, at 4:32 PM, Roger Furneaux roger.46tc@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: hi Len - I'm not sure what a thread restorer for a tapped hole looks like, but the threads are unlikely to be damaged, only full of baked-in oil. A 2nd. -cut tap will clean out this grunge, especially at the bottom. In fact, this should be done with all the other stud holes when rebuilding an engine The most important thing about studs is that no threads should be outside the block. I read in an engineering journal about tests that had been made, and the best result was obtained by having the block slightly counterbored with the diameter of the studs, second best was no counterbore (but chamfered) and worst of all was not fully seated (either because not chamfered or stud bottoming out). Loctite is not needed (the threads will deform on torqing up and lock themselves) and they only need to be finger-tight. When it comes to the nuts it is vital that they are neither under nor 0ver-torqed: by swapping nuts around you can usually get them all just right (63 + or - 2 lbsf. ft.) but if not use the old trick of removing a few thou from the nut (either on a lathe or fine abrasive sheet on a flat surface). Failure to attend to all these details will quite likely lead to failure of the stud itself. oc[b]T[/b]agonally Roger On Mon, Sep 3, 2018 at 7:26 PM laf48@aol.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u] Sherwood I have always bottomed them out with a stud remover / replacer or double nuting them. Make sure the hole is clean and dry with a "Q" Tip, NO oil in the hole as the hydrostatic lock will crack the housing. Also if the threads need cleaning use a thread restorer, not a cutting tap. Hope this helps Len Fanelli Abingdon Performance Ltd. -----Original Message----- From: Sherwood Parker sherparker1@msn.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> To: TABC List mg-tabc@yahoogroups.com> Sent: Mon, Sep 3, 2018 2:02 pm Subject: [mg-tabc] Best Practices? Listers, What are the "best practices"for installing studs for the Main Bearing Caps and for the Head? I have heard "bottomed out", "bottom out then back of 1/4 turn", "gently tight", "Locktite" (color) and "nothing out of the ordinary". I would appreciate all learnings. Thanks in advance, Sherwood Parker TC8355 Tempe, AZ, USA[b]From:[/b] Bill Hyatt usaj24@earthlink.net> [b]Date:[/b] September 3, 2018 at 6:33:41 PM EDT [b]To:[/b] mg-tabc@yahoogroups.com [b]Subject:[/b] [b]Fwd: [mg-tabc] Best Practices?[/b]
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