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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Mechanical Maintenance: Break-in / Oil & Fluids / Servicing / Warranty > n52 (Magnesium cover)



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      10-02-2017, 04:15 PM   #1
praveenkrs
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n52 (Magnesium cover)

Hi all,

First post here, long time lurker. I had a leaking Valve cover gasket ( the orange metal crush one). I had aluminum bolts on it, so replaced the set. Now here's the dumb part, I read online guides and hastily read the torque specs as 10Nm. I had a tough time torquing those bolts to that and i think I stripped a couple.

After coming back and double checking torque specs from the Bentley I see it's 65 lbin. ~7Nm. So I've over-torqued the bolts by quite a bit and stripped a few in the process.

Now, on a scale of 1 to Royally fucked, how screwed am I? I tested the car after reassembly and it's running fine no leaks/smoke except the 1st few minutes min due to random oil spills i'm guessing.

Should I order fresh parts and just do it again, or wait until it leaks. If the bolts break I'll be in a LOT of pain, right?

Thanks
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      10-03-2017, 07:15 AM   #2
Efthreeoh
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I doubt you stripped any of them. And you over-torqued them by very little if any. Unless you cross-threaded the bolts going in, it's not likely you stripped any of the bolts. Did you finger tighten the bolts down first untill they seated on the valve cover? Where any of the bolts difficult to finger thread into the cylinderhead? If not then none cross-threaded. Any application of over torque would easily snap the aluminium bolt before it would damage the threads in the bolt holes of the cylinderhead.

Just leave it alone and keep an eye out for leaks in the next few weeks. If the aluminium bolts are beyond their stretch yield they could snap the head of the bolt off later as the engine heat cycles.

I'd not worry about it. Just a question, but usually the OEM bolt kit comes in a bag with a card that explains the torque sequence. IIRC it is 65 inch-pounds + 90 deg, so applying a small amount of over-torque without the angle spec is probably equal to the additional 90 deg. Did your bolt kit come with that information?
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      10-03-2017, 12:58 PM   #3
praveenkrs
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Thanks for the reply.
I had ordered this kit from fcp euro (BMW Valve Cover Gasket Kit - 11127581215KT) , and no there was no torque guidance in the pouch. I'll watch for leaks and hope for the best.
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      10-03-2017, 01:00 PM   #4
praveenkrs
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Quote:
Originally Posted by Efthreeoh View Post
Did you finger tighten the bolts down first untill they seated on the valve cover? Where any of the bolts difficult to finger thread into the cylinderhead?
Yes, I finger tightened all of them to the valve cover and ratcheted them only a couple of rotations
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      10-03-2017, 01:48 PM   #5
hassmaschine
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The aluminum bolts are TTY and honestly, pretty forgiving. Why do you think you stripped them? Did they come loose after you torqued them to 10nm? I would think the aluminum bolts would be far more likely to shear off at the head than strip the threads.
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      10-03-2017, 02:39 PM   #6
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Quote:
Originally Posted by hassmaschine View Post
The aluminum bolts are TTY and honestly, pretty forgiving. Why do you think you stripped them? Did they come loose after you torqued them to 10nm? I would think the aluminum bolts would be far more likely to shear off at the head than strip the threads.
Stripped them i.e sheared the head and stripped some of the star shaped head. I don't think I stirpped the threads.
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      10-03-2017, 03:15 PM   #7
hassmaschine
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torx bolts are pretty forgiving to stripping. If you use an impact driver, or hammer a smaller torx socket on there, I'll bet you can get it off easy enough.

But unless they are sheared off at the shank I would just leave them be.
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      10-03-2017, 03:49 PM   #8
praveenkrs
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Quote:
Originally Posted by hassmaschine View Post
torx bolts are pretty forgiving to stripping. If you use an impact driver, or hammer a smaller torx socket on there, I'll bet you can get it off easy enough.

But unless they are sheared off at the shank I would just leave them be.
Thanks! that's a relief! So I suppose I just wait for 50-60k miles for the gasket to leak again to worry about it.
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      10-03-2017, 05:15 PM   #9
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basically. I live by the motto "if it ain't broke, don't fix it".
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      10-03-2017, 10:17 PM   #10
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Quote:
Originally Posted by praveenkrs View Post
Stripped them i.e sheared the head and stripped some of the star shaped head. I don't think I stirpped the threads.
You should try to be accurate in what you write. The term "stripped" in the parlance of bolts customarily means thread damage and not sheared bolt shanks.
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      10-05-2017, 05:09 AM   #11
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Quote:
Originally Posted by Efthreeoh View Post
You should try to be accurate in what you write. The term "stripped" in the parlance of bolts customarily means thread damage and not sheared bolt shanks.
Thanks, will do. Completely new to terminology.
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