N52 Alternator Mounting Bolt Torque?

vachss · 08-08-2015, 09:24 AM

Alternator on the 3.0si Coupe is finally going at 150K miles. Not a particularly big job, but I'm finding conflicting info on the torques required for the 4 Aluminum mounting star bolts shown below:

Since these are AL and stretch I really don't want to overtighten. Anyone have a good torque number (I've variously heard 14 ft lb and 31 Nm and am inclined to believe the first number, but real info would be nice).

Thanks!

JFleming · 08-09-2015, 08:54 AM

My BMW manual says 10Nm plus 180 degrees. They also caution that the aluminum bolts cannot be reused.

vachss · 08-09-2015, 10:07 AM

Thanks! Got the fresh bolts and that's what I'll use.

3002 tii · 08-09-2015, 05:51 PM

Quote:

Originally Posted by vachss

Alternator on the 3.0si Coupe is finally going at 150K miles. Not a particularly big job, but I'm finding conflicting info on the torques required for the 4 Aluminum mounting star bolts shown below:

Since these are AL and stretch I really don't want to overtighten. Anyone have a good torque number (I've variously heard 14 ft lb and 31 Nm and am inclined to believe the first number, but real info would be nice).

Thanks!

150k, that's what I'm talking about!!!

vachss · 08-09-2015, 06:58 PM

Quote:

Originally Posted by 3002 tii

150k, that's what I'm talking about!!!

Knock wood. Other than wear items (brake pads, shocks, various bushings) the only repairs the car has needed have been a new battery at 115K, water pump at 135 and now the alternator at 150. Still runs great - no complaints. Did the 20th oil change at the same time as the alternator.

Other than Inspection I at the dealer (and the water pump - when I was in a hurry, got weak and gave it to a local indy) I've done all the work myself. When I anthropomorphize I like to think the car appreciates that.

3002 tii · 08-09-2015, 07:10 PM

My N52 only has 70k but half are hard driven track miles. Car has been really reliable, and the only annoyances I've dealt with are the vanos solenoids and coil packs going around at 45k. When did you change your plugs?

vachss · 08-09-2015, 07:40 PM

Quote:

Originally Posted by 3002 tii

My N52 only has 70k but half are hard driven track miles. Car has been really reliable, and the only annoyances I've dealt with are the vanos solenoids and coil packs going around at 45k. When did you change your plugs?

Plugs at 100K as part of Home Brew Inspection II. The old plugs looked pretty much unworn and I didn't notice any change in behavior when I swapped the new ones in.

08-08-2015, 09:24 AM	#1
vachss Captain 55 Rep 815 Posts Drives: Z4 Coupe Join Date: Jan 2008 Location: Ventura County, CA iTrader: (1)	N52 Alternator Mounting Bolt Torque? Alternator on the 3.0si Coupe is finally going at 150K miles. Not a particularly big job, but I'm finding conflicting info on the torques required for the 4 Aluminum mounting star bolts shown below: Since these are AL and stretch I really don't want to overtighten. Anyone have a good torque number (I've variously heard 14 ft lb and 31 Nm and am inclined to believe the first number, but real info would be nice). Thanks! Last edited by vachss; 08-08-2015 at 07:08 PM..
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08-09-2015, 08:54 AM	#2
JFleming Private 9 Rep 51 Posts Drives: '10 328i xdrive, '07 Z4 3.0si Join Date: Jan 2011 Location: Cleveland OH iTrader: (0)	My BMW manual says 10Nm plus 180 degrees. They also caution that the aluminum bolts cannot be reused.
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08-09-2015, 10:07 AM	#3
vachss Captain 55 Rep 815 Posts Drives: Z4 Coupe Join Date: Jan 2008 Location: Ventura County, CA iTrader: (1)	Thanks! Got the fresh bolts and that's what I'll use.
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08-09-2015, 07:10 PM	#6
3002 tii Lieutenant General 2280 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.20]	My N52 only has 70k but half are hard driven track miles. Car has been really reliable, and the only annoyances I've dealt with are the vanos solenoids and coil packs going around at 45k. When did you change your plugs? __________________ Follow for latest mods
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