Breaking Harmonic Balancer Bolts

[iDriftYou]

So I've had this happen twice now, first factory harmonic balancer failed broke 5 bolts along with it, shop who did crankhub reused my CBC bolts and did not loctite, I was able to get the broken bolts out fairly easily. I replaced my balancer with an ATI super dampner, got new bolts from hardware store and loctited them in. Drove the car around, much smoother now, fast forward 2 months, just doing an overview and come to find out another 4 bolts have snapped off. I'm ordering ARP bolts and hopefully this solves the issue. I have a spec twin disk clutch with a single mass lightweight flywheel, is that causing the bolts to brake? Any advice is appreciated.

Car is a F80 Comp 6MT.

[JAI///M3]

Seems to be somewhat commin with low quality fasteners included with CBC kits

https://f80.bimmerpost.com/forums/sh....php?t=2032664

[AlmondJayRoM3]

Originally Posted by JAI///M3

Seems to be somewhat commin with low quality fasteners included with CBC kits

https://f80.bimmerpost.com/forums/sh....php?t=2032664

Don’t have to be an engineer to see the failure point of the CBC kits picture in the links. World’s strongest bolts mean nothing if there isn’t sufficient surface area for them to clamp on to. There’s so little surface area on the actual crank bolt capture plate that the bolts are digging in into the material and eventually wearing away at it resulting in a loss of tension. Typically this is rectified by using washers but doesn’t look like there’s enough room for them. This is just what I can pick out from the pictures so there can also be more to it.

[jfritz27]

I have the Kies capture plate, and I found it interesting that it uses a singular large circular washer (with holes punched around its circumference for each bolt). I wonder whether this approach leads to less of these kinds of failures

[JAI///M3]

Originally Posted by jfritz27

I have the Kies capture plate, and I found it interesting that it uses a singular large circular washer (with holes punched around its circumference for each bolt). I wonder whether this approach leads to less of these kinds of failures

I have the same version (not yet installed) and hoping for the same. I’ll still replace the hardware for peace of mind.