Correct torque for an 8mm turbine stud?
#1
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Correct torque for an 8mm turbine stud?
While fiddling with the downpipe and wastegate I managed to shear two studs (stover nuts did not want to come off). Begi was kind enough to send me some replacements. Using the double nut method what should I torque the 8mm studs to on the turbine exit. Then, what should the nut be torqued to once the downpipe is back in place?
#2
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no one knows? There seems to be some confusion (or at least I'm confused) as to whether you tighten the studs into the turbine with half the torque you will be applying to the nut once the downpipe is in place or if you should rather torque to the studs into the turbine housing twice what you will apply to the nuts. Any specific figures I should be shooting for? I'd rather not shear any more studs out of sheer (haha) ignorance.
#3
I say lube the studs with that super slick moly **** (look it up), and torque to like 25 ft*lbs. Make sure you chamfer the manifold where the studs go in so that the two tapers meet each other. Then do the nuts to like 15 ft*lbs. Those numbers are just out of my ***, but should work. FWIW, there are charts that show bolt diameter/torque values.
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I'd imagine the turbine housing is chamfered already as the studs came preinstalled from Begi. I'm just replacing some I broke. I also figured there were charts, but #1 I don't know where to find them and #2 I wasn't sure if heat and vibration would effect the value of the numbers. Thanks for the tips, I would not have guessed the torque values would be so low. I probably would have sheared one again.
#10
If you are using the deformed nuts you'll either end up backing the stud out when you go to remove the stud, or you'll break the stud. Like Tim suggests, less is more.
I'd rather deal with a lost nut or having something come loose than a stud broke off in the turbo. This is why I use nordlocks on the turbo and downpipe.
I'd rather deal with a lost nut or having something come loose than a stud broke off in the turbo. This is why I use nordlocks on the turbo and downpipe.
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"Nord Locks" ehh...thanks for the name. I know FM sells them.
FM: http://www.flyinmiata.com/index.php?...umber=36-30300
$1.95 per pair stainless
McMaster: #91074A130 Mild steel, $0.52 per pair (but you have to buy 25 pair hehe)
#91812A230 316 stainless, $1.53 per pair, comes in a bag of 5 pair, perfect for a downpipe.
I'm so cool that McMaster moved their NJ location right onto my way home from work. They love me that much. Will call FTMFW especially when you buy lots of heavy weldells for manifolds and such
FM: http://www.flyinmiata.com/index.php?...umber=36-30300
$1.95 per pair stainless
McMaster: #91074A130 Mild steel, $0.52 per pair (but you have to buy 25 pair hehe)
#91812A230 316 stainless, $1.53 per pair, comes in a bag of 5 pair, perfect for a downpipe.
I'm so cool that McMaster moved their NJ location right onto my way home from work. They love me that much. Will call FTMFW especially when you buy lots of heavy weldells for manifolds and such
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