may not be the right place to post this. Mods, feel free to move where you see fit.

I have a D17 I'n my 2001 Civic. Changed the timing belt and a pile of other misc. Items. When rotating the crank/cam in order to ensure alignments. I got a little lazy and opted to rotate the motor via the cam shaft pulley mounting bolt (didn't have to bend down like I would have needed to in order to reach the crank bolt). The spark plugs were still in the motor so it did have some resistance. I was clever enough the set my torque wrench well below the required torque rating spec'd for the bolt. As I was rotating the motor, the cam shaft pulley bolt snapped. ... I then tried to drill it out enough to put an easy out on it and back it out. Drill bit started to wander... ** pulled the rocker assembly off and removed the cam shaft... I guess I was due for a valve adjustment anyhow ... Took the cam with the busted bolt to the local motor shop. $66 later, the bolt was out and a new bolt was in hand and ready to go.

The guys at the shop brought to my attention that the bolt was previously fractured and as such, I didn't really cause the issue. They showed me where the shiny break on the bolt was... This is where I broke it. Then they showed me a darker discoloration and said that this is where old break/fracture had been (more than half the surface are of the break was dark). This is the first time the motor has ever been cracked open so this bolt was fractured right from the factory. That's right... 193,000K and the first timing belt change. Interestingly enough, the original belt showed virtually no cracking and very little glazing when I inspected it. Now that my wife is using this car daily for commuting purposes, I wasn't sleeping well knowing I had neglected it for so long.

Two things here... #1: OEM is not always better (this fractured bolt was definitely OEM) and #2: if you break a bolt, it might not be your fault so don't be too hard on yourself... $hit happens!