Cam Bolts Broken After Replacement

[Sid_E46]

So my friend's 06 M3 had its cam bolts replaced with the updated torx head BMW bolts which proceeded to snap just like the previous bolts in 12k miles. Is there a possibility that the previously snapped bolts damaged the threads and caused this to occur once again? Has anyone experienced something like this or recommends a different type of bolt?

[sapote]

Did he use Loctite on the bolts threads

[sapote]

It’s not about stronger bolts, but it needs to prevent them from backing out by using Loctite

[Obioban]

Did he use Loctite on the bolts threads

100% this. The issue with those bolts is them getting loose over time. Original bolts, updated bolts, aftermarket bolts, doesn't matter-- the key is installing them correctly (torque spec and loctite).

[maupineda]

My same question, if Loctite was not used, or, the assembly was not cleaned so that the Loctite did not bond, that would be the issue.

[sapote]

I'm interested of seeing the cam sleeve 6 holes, and how bad they had been distorted after hammering on the bolts to cut a notch.

[Sid_E46]

It’s not about stronger bolts, but it needs to prevent them from backing out by using Loctite

Red Loctite was used, and it was torqued properly according to my knowledge. Can even slight over-torque cause this?

[Sid_E46]

I'm interested of seeing the cam sleeve 6 holes, and how bad they had been distorted after hammering on the bolts to cut a notch.

We did not use a hammer to remove the previously snapped bolts, just used a pick and spun them out. We wouldn't have even caught this if we weren't swapping out his cams.

[sapote]

We did not use a hammer to remove the previously snapped bolts, just used a pick and spun them out. We wouldn't have even caught this if we weren't swapping out his cams.

Not as a tool, but the hammering effect when there was plays between the sleeve and the loose bolts.

[Sid_E46]

Not as a tool, but the hammering effect when there was plays between the sleeve and the loose bolts.

Oh ok, I'm not quite sure. The car is getting new cams so let's hope it doesn't happen again. We will probably use a decent bit more red loctite this time.

What torque is recommended for these bolts? And does going over that number a little pose a risk?

[Slideways]

Oh ok, I'm not quite sure. The car is getting new cams so let's hope it doesn't happen again. We will probably use a decent bit more red loctite this time.

What torque is recommended for these bolts? And does going over that number a little pose a risk?

Loctite 243 is oil tolerant; the standard blue loctite 242 and red are not.

[Sid_E46]

Loctite 243 is oil tolerant; the standard blue loctite 242 and red are not.

We used the red gel loctite, that isn't oil resistant?

[Slideways]

It is stated on the 243 -

[maupineda]

I think the issue is you did not use the right locker and again, should be as clean of oil as possible.

[Sid_E46]

We are going to use the lang racing bolts and 243 loctite this time. Is 9 ftlbs the recommended torque?