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      03-05-2017, 10:28 AM   #41
GuidoK
#buildnotbought
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Drives: Z4 3.0i ESS TS2+
Join Date: Jul 2012
Location: Tinkering in the garage

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Quote:
Originally Posted by JJZ4MR View Post
The large plate on bottom of motor.
Those bolts are already 10.9 I think?!?
Have you had them physically in your hands? I think it is stamped on the hex head. (both the 10.9 grade and probably something like ZNF (zinc plated (ZN), fine thread (F))
And indeed they should have an integrated washer, otherwise the aluminium plate will be damaged.
And that washer probably has a little crosshair on the reinforcement plate side to ensure that on that side is more friction so that while torquing the movement takes place between washer and bolt head.
Might be difficult to find all that in an aftermarket bolt

I usually reuse these bolts (I've had that plate on&off so many times...), but you can see that over time, the threads on the hex side will start to stretch a bit, so you cant reuse them indefinately (and shows that they are indeed stretch bolts and no ordinary bolts). Maybe I'll change them in the near future.
I also dont torque them to the full 90deg, more like 60, because they are used.


Upgrading bolts doesnt have a real meaning if you're not going to apply more torque though, unless there is a design flaw which causes the bolts to break. But that usually doesnt happen with axial forces but with lateral forces.
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Z4 3.0i | ESS TS2+ supercharger | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | Powerflex/strongflex PU bushings | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers/KW camber plates | Sachs race engineering clutch | tons of custom sh#t

Last edited by GuidoK; 03-05-2017 at 11:05 AM..
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