Since the subject of timing belts came up you wanna see some carnage? I got it.
Background: 2004 Honda Civic Coupe. D17 engine. Bought new in June 2004. On December 15, 2010 at 117953 miles (189K km) had a shop replace the timing belt, tensioner and water pump. I was going to do it myself but didn't have the time. I provided the shop with the parts and they did the labor.
Exactly 1 year later, December 13, 2011 at 134293 miles (216K km). I was doing a routine shift from 1st to 2nd gear. There was a loud bang and the engine shut down. Would not restart. Noticed the starter was spinning super fast so I suspected that the timing belt snapped.
Had it towed to a different shop. Engine teardown. Confirmed....broken timing belt. They were going to pull the head and see the extent of the damage. All 16 valves bent. They checked the bottom end of the engine (Pistons, connecting rods, crankshaft, etc) and the shop determined that there was no additional damage. Recommendation was to rebuild the head. I agreed. The shop could not determine why the belt broke but they suspected that the tensioner spring popped and allowed the belt to come off.
One of the 16 bent valves
The shredded belt wrapped around the tensioner
The shop found the mangled tensioner spring down by the crankshaft pulley
When the belt snapped it also broke the crankshaft position sensor. That piece of plastic was $100 USD
The Civic was in the shop for 2 weeks while the head was out for rebuild. Total cost was just over $2K USD. The shop did excellent work. Ran fine.
I still own the Civic and up until June of 2016 it was a “daily driver”. It has just under 187K miles (301K km). It's now in semi-retirement and driven once or twice a week. There have been no ill effects from the timing belt disaster in 2011. No increase in oil consumption, no odd noises. Runs great!