Technical need help from engine builders / n54 issues :(

[ripn54]

"Hi,
I’m working on an ‘07 N54 engine that I’m refreshing. When setting up the camshaft timing, I used the old bolt to verify everything was in time. I carefully checked the camshaft threads and the bolt, and both were undamaged. The old bolt torqued to spec (20 Nm + 180°) without any issues.

However, when I replaced it with a new bolt, the threads inside the camshaft stripped after only about 50°. I’m not sure why this happened.

I went to a BMW dealership and spoke to a master technician, but they only work on N55 engines. They recommended cleaning the threads, applying thread locker, and tightening the bolt until it bottoms out, but I’m not confident in that solution.

Should I try a helicoil repair, or would it be better to replace the camshafts? I’m worried this might happen with the new camshafts too.
How can I prevent this issue?
Any advice would be greatly appreciated!"

 

[ShocknAwe]

I have N54 camshafts in my garage if you want them.

I would not feel comfortable "applying thread locker and torquing until it bottoms out" on a set of threads that just stripped.

 

[ripn54]

I have N54 camshafts in my garage if you want them.

I would not feel comfortable "applying thread locker and torquing until it bottoms out" on a set of threads that just stripped.

Thanks a lot, I really appreciate it.
I live in the UAE, that's not a good option ,
and at this point, I’ve reached 65 Nm of torque but haven’t applied the angle torque .
I’m waiting for the helicoil kit to arrive so I can reinforce the threads to better handle the pressure.
I believe this is the best solution available right now.

 

[ShocknAwe]

Thanks a lot, I really appreciate it.
I live in the UAE, that's not a good option ,
and at this point, I’ve reached 65 Nm of torque but haven’t applied the angle torque .
I’m waiting for the helicoil kit to arrive so I can reinforce the threads to better handle the pressure.
I believe this is the best solution available right now.

Yeah might be a bit to ship them there.

 

[Maroon_e90]

Theres a good chance the new bolt was not torque to yield so it did not stretch when applying the additional 180°. Either way that cam shaft should not be used. when the phaser will inevitably slip there will be a lot of damage to the head, pistons and maybe even rods.

As for preventing the issue, I would suggest getting a torque reading from the old bolt at the 180° mark and then installing the new bolt to that torque without additional angle.

 

[ShocknAwe]

I would not stretch the old bolt again...

 

[ripn54]

Theres a good chance the new bolt was not torque to yield so it did not stretch when applying the additional 180°. Either way that cam shaft should not be used. when the phaser will inevitably slip there will be a lot of damage to the head, pistons and maybe even rods.

As for preventing the issue, I would suggest getting a torque reading from the old bolt at the 180° mark and then installing the new bolt to that torque without additional angle.

I noticed a difference between the old and new bolts—the new one is about 1/2 inch shorter.

Based on my research, the torque spec of 20 Nm + 180 degrees translates to approximately 65 Nm

However, the issue started when I switched to the new bolt.

I'm not entirely sure, but I think there’s a difference in the material. The new bolt seems tougher compared to the old one.
I bought new bolts from ECS, and then I got another set from the dealership, but I ended up with the same result both times.

 

[ripn54]

I thoroughly inspected all the threads, and they are in perfect condition with no damage whatsoever.

The new bolts feel stronger, possibly because the old bolts have stretched over time.

I just wanted to share this, it might help someone in the future.

 

[Maroon_e90]

Those look like they are the wrong bolts. The bolt is not going to stretch that much. Makes sense why the first few threads stripped since that is all the shorter bolt was able to reach.

How did you measure the bolts? They are supposed to be m10-1 x 94mm.

 

[ripn54]

Those look like they are the wrong bolts. The bolt is not going to stretch that much. Makes sense why the first few threads stripped since that is all the shorter bolt was able to reach.

How did you measure the bolts? They are supposed to be m10-1 x 94mm.

The part number 11367524954 refers to bolts with specifications M10x1 and a length of 94mm, as officially stated.

I initially received these bolts as part of the IWIS kit 59004Set, which is the manufacturer BMW uses.

Later, I ordered another set of bolts directly from the dealership, matched to my VIN.

Interestingly, the bolts from the dealership are identical to the ones I received with the IWIS kit, but they differ from those originally installed in the car.

 

[ripn54]

A quick update!

I noticed a difference in length between the old bolt and the new one.

The measurement from the VANOS sprocket to the end of the camshaft thread is approximately 99 mm.

I ran a small experiment: each day, I stretched the bolt by tightening it around 25 to 40 degrees until I felt it was close to breaking. I repeated this process daily until I reached a total of 180 degrees. After removing the bolts, they both measured around 94 mm, indicating they stretched but held up well. However, applying the full torque in one go seemed to strip the threads — I’m not entirely sure why, but that's what I observed during the test.

For now, I’ve reused the old bolts, applied Loctite, and tightened them to 67 Nm (about 20 Nm + 180 degrees). I haven’t started the engine yet to test it.

 

[Maroon_e90]

something is not adding up... 180 degrees should only stretch the bolt 0.5mm

 

[ripn54]

something is not adding up... 180 degrees should only stretch the bolt 0.5mm

That's what I thought, but I tested it, and the result was approximately the same length, around 94 mm.