Stripped exhaust manifold stud in housing
#26
Not sure loctite will do much, other than before first start-up, permitted upper temp range is somewhere around 200C from what I remember.
The grip section of the stud should be the stop when it contacts the timesert, so not sure how that is working, unless the timesert counterbore is deeper and torquing it is winding it in? I'd be wary running a tap through too, idea is the fastener forms it's own threads, at the lower levels at least....might be tempted to remove and reinstall a new one. Only time I've worried about torque on the studs in that area are turbo to manifold, where you could crack stuff if you go nuts.
The grip section of the stud should be the stop when it contacts the timesert, so not sure how that is working, unless the timesert counterbore is deeper and torquing it is winding it in? I'd be wary running a tap through too, idea is the fastener forms it's own threads, at the lower levels at least....might be tempted to remove and reinstall a new one. Only time I've worried about torque on the studs in that area are turbo to manifold, where you could crack stuff if you go nuts.
I have other inserts I could install but I am not sure how safe it is to remove this one. If I damage the new threads in the aluminum that I tapped with the timesert kit, I will really be stuck.
#27
Penis Healthy
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I dunno how you botched it man. the Bevel tool should stop the insert from spinning without damaging the threads. did you use it? You could always jb weld it into place and pray, but i dont want to be responsible for any bad ideas.
^^^^Cancel that, didnt see your last post.^^^
Are you sure you bought the correct thread pitch?
^^^^Cancel that, didnt see your last post.^^^
Are you sure you bought the correct thread pitch?
#28
I dunno how you botched it man. the Bevel tool should stop the insert from spinning without damaging the threads. did you use it? You could always jb weld it into place and pray, but i dont want to be responsible for any bad ideas.
^^^^Cancel that, didnt see your last post.^^^
Are you sure you bought the correct thread pitch?
^^^^Cancel that, didnt see your last post.^^^
Are you sure you bought the correct thread pitch?
#29
Here's a picture of the stud as it currently sits, and you can see the timesert flange is flush and not deeper than it should be. The stud is maybe 1mm deeper than the others. I am also now getting the 'click' when I tighten it at 22ftlbs although I am not sure how much of that is from the two drops of loctite I used.
Last edited by derSchwamm; 01-02-18 at 08:19 PM. Reason: picture
#30
Rotary Freak
The insert is definitely not twisting deeper. I didn't get a picture unfortunately but the first row or two of threads were definitely getting flattened by the flat middle of the stud. I only ran a tap through the outer end to clean it up a bit, but not all the way through the insert.
I have other inserts I could install but I am not sure how safe it is to remove this one. If I damage the new threads in the aluminum that I tapped with the timesert kit, I will really be stuck.
I have other inserts I could install but I am not sure how safe it is to remove this one. If I damage the new threads in the aluminum that I tapped with the timesert kit, I will really be stuck.
#31
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Bro if you have a click at 22 id just leave it. Id be comfortable with 22ftlbs and having the stud at least flush with the top of the nut when the manifold is installed.
and the only part of the timesert threads that should be smaller is the end that locks it into place.are you sure you put the driver tool in enough?
and the only part of the timesert threads that should be smaller is the end that locks it into place.are you sure you put the driver tool in enough?
Last edited by FührerTüner; 01-02-18 at 08:29 PM.
#32
Yeah, I'm just going to continue with my build at this point. If it's not at the factory torque spec, it's close enough. I feel like I won't be able to get it any better and I'm tired of messing with it.
And yeah, I know how the timeserts work and which end should have shorter threads, but the end with the flange is what's giving me trouble (not what you circled here). Once you get to the 20ftlb ballpark the tapered flat part of the stud just starts compacting those threads, driving the stud in further. It was a new m10x1.5 insert, and a new stud, and a torque wrench set to 22ftlbs, and the insert didn't move. Don't really know what else to say
I did previously get the manifold installed, and I got the nuts torqued correctly on all 4 (50-something ftlbs). I'm pretty confident I can torque them down to that again even on this stud, so as long as the stud doesn't back out in the future it should be ok. I'm a perfectionist though and I really wish I could be 100% confident in this fix
And yeah, I know how the timeserts work and which end should have shorter threads, but the end with the flange is what's giving me trouble (not what you circled here). Once you get to the 20ftlb ballpark the tapered flat part of the stud just starts compacting those threads, driving the stud in further. It was a new m10x1.5 insert, and a new stud, and a torque wrench set to 22ftlbs, and the insert didn't move. Don't really know what else to say
I did previously get the manifold installed, and I got the nuts torqued correctly on all 4 (50-something ftlbs). I'm pretty confident I can torque them down to that again even on this stud, so as long as the stud doesn't back out in the future it should be ok. I'm a perfectionist though and I really wish I could be 100% confident in this fix
#34
I forgot how much trouble I had with this a year ago! It seems to be holding up. I've put 2000 miles on the car since the rebuild, a lot of which was lighter driving since I was breaking it in. I've gotten into full boost a couple time recently and I have yet to see any evidence of an exhaust leak. I'm pulling the turbos soon to install BNRs so I'll take a look and make sure the stud hasn't backed out or anything, so I'll report back after then.
FYI I've used helicoils quite a bit and they are good, but the timesert definitely seems more durable. I'd recommend it for something this important
FYI I've used helicoils quite a bit and they are good, but the timesert definitely seems more durable. I'd recommend it for something this important
#40
When I torqued it down, a few seconds later I heard a pop and the stud had popped backwards and taken the threads with it. This was due to the tension from the lock washer. Aluminum threads are weak and apparently this can happen. Mazda didn't use them from the factory so I shouldn't have either. It's happened once on the head of my protege too (also aluminum, at the exhaust manifold)
#41
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When I torqued it down, a few seconds later I heard a pop and the stud had popped backwards and taken the threads with it. This was due to the tension from the lock washer. Aluminum threads are weak and apparently this can happen. Mazda didn't use them from the factory so I shouldn't have either. It's happened once on the head of my protege too (also aluminum, at the exhaust manifold)
#42
Racecar - Formula 2000
Absolutely correct. Once the threads sheared off, THEN the lock washer popped the stud further out.
#46
TANSTAFL
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The FSM torque spec is for a prevailing torque nut without anti-seize lubricant on it. Both of those variables will change the required torque to get the desired bolt stretch and clamping force.
Fasteners are generally torqued to ~75% of their rated strength and the use of a lubricant like anti-seize alone has been said to reduce required torque by 30-50%.
Get rid of the crimped prevailing torque nut, put some anti-seize on your threads, then torque to FSM spec.... doesn't take much imagination to predict what happens next.
https://www.engineeringtoolbox.com/b...or-d_2065.html
Fasteners are generally torqued to ~75% of their rated strength and the use of a lubricant like anti-seize alone has been said to reduce required torque by 30-50%.
Get rid of the crimped prevailing torque nut, put some anti-seize on your threads, then torque to FSM spec.... doesn't take much imagination to predict what happens next.
https://www.engineeringtoolbox.com/b...or-d_2065.html
#48
Ban Peak
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Bumping because this forum is such a great resource. The block I’m dressing had one stud that was different, I replaced it with a new OEM and sent it home without checking torque. I probably damaged what were already compromised threads more. When I bolted up the turbo manifold using stainless washers and new OEM nuts it got tight…. and then I felt the unsettling feeling of it tightening a little too easy. Sure enough, it pulled the threads.
The manifold and turbo are back off an I’m waiting on a time-sert kit. I’m going to put it in correctly with loctite and then I hope I can torque to 50ftlbs on all the nuts. The other 3 studs seemed to tightened up fine and I hit torque on the top front prior to the failure of the top rear.
The manifold and turbo are back off an I’m waiting on a time-sert kit. I’m going to put it in correctly with loctite and then I hope I can torque to 50ftlbs on all the nuts. The other 3 studs seemed to tightened up fine and I hit torque on the top front prior to the failure of the top rear.
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