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Starter bolt torque spec

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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ted928
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Starter bolt torque spec

Post by ted928 » Tue Jun 28, 2022 2:19 am

What are the bolt torque specs?
I downloaded 'BMW Z4 2.8i3.0i3.5i3.5is 2009-2016 Workshop Repair & Service Manual.pdf' and it says to replace aluminum bolts and table 12 41 states a torque of 38 Nm. When I tried to install new aluminum bolts, the bolt snapped before I reached the target torque. I checked the calibration of my torque wrench and it is accurate. Is 38 Nm for steel bolts and there is a different spec for the aluminum bolts?
2009 Z4 S-drive 30i E89 N52

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B21
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Starter bolt torque spec

Post by B21 » Tue Jun 28, 2022 9:46 am

The torque setting seems correct…can’t access real oem at the moment but would be surprised if those were aluminium alloy bolts…10mm not a lot of meat for such an application..?
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ted928
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Starter bolt torque spec

Post by ted928 » Wed Jun 29, 2022 10:49 pm

Looks like the correct torque for the aluminum bolts are 20 Nm + 90 degrees for the short bolt, and + 180 degrees for the long bolt.
viewtopic.php?p=1936583#p1936583
Thanks
2009 Z4 S-drive 30i E89 N52

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