Question. Started my cooper up after rebuild. It ran crappy. I bothered many people and a local shop responded with a solution. I surrendered and had them look at my engine. They concluded that the vanos was in the wrong orientation on the camshaft and while thinking the orientation when the cams locked in place shouldn't matter I let them do their thing. The problem is that they re-torqued the cam using the original bolt that was already fully torqued. Now my OCD has kicked in telling me to replace the twice-torqued cam bolt with a new one. Am I crazy or should I suffer the brain damage to replace the bolt and retime the cams?
Help. DR

 

Yup, those are one time use bolts

 

I am swapping the bolt today.

 

I replaced the head and head gasket on my 2011 MCS about 17k miles ago, had a buddy who is a BMW tech help me. He said the orientation of the vanos sprockets to the cams didn't matter at all as long as the cams and crank were locked. My Bentley manual confirmed this. Did yours run better after the shop did the work? Regardless, I would do just as you are doing and replace any TTY bolts they didn't.

 

So upset to be going down this path again. I have couple more new bolts in stock so I'll just record the effort on video. When you ask a tech to do something why do they conveniently not hear you. It's like a child - selective hearing. The first time I did this it failed. So I worked with it and made all the adjustments necessary to get the cam perfectly aligned with the tool. I even checked the position of the pistons with long straws. Everything was spot on... Thanks for the response. DR

 

Did you pre tension the timing chain?

 

And make sure you check for bent valves. If your VANOS sprocket spun on the camshaft, it's possible the piston contacted a valve (or two). I messed up on my first timing chain job. In the Bentley service manual there is one torque spec for the N14 and another for the N12, N16, and N18. For the N14, the 1st stage is 15 ft lbs; 2d stage is an additional 90 degrees. For the other engines it's 15 ft lbs; 2d stage is an additional 180 degrees. I followed the N14 step on my N12 and it slipped ... bent 3 valves.

I have a Proto digital torque angle meter, and the cool part about this tool is that after you reach the angle you program into the tool, it will alternately flash the number of degrees you turned the fastener and the final torque value.




I just finished installing a repaired cylinder head on a 2012 N16 engine and I wrote down all the final torque values for each bolt including the crankshaft hub bolt. Final torque values looked like this:

Final cylinder head bolt torque (in numbered sequence order of the manual):
1. 57.9
2. 59.1
3. 56.2
4. 56.9
5.58.5
6. 58.9
7. 61.9
8. 60.8
9. 58.3
10. 54.9
4th torque step was to put all bolts at 60 ft lbs. Bolts 11-13 are undersized and have a lower torque value.
11. 31.9
12. 34.7
13. 23

hub bolt torqued to 37 ft lbs, and then rotated 180 degrees; final torque was 137 ft lbs

Ex Vanos torqued to 180 in lbs, 90 degrees, and an additional 90 degrees; final torque value was 61.1 lbs.

In Vanos torqued to 180 in lbs, 90 degrees, and an additional 90 degrees; final torque value was 63.3 ft lbs.