Pat McMahon and I took the broken Coyote engine out of FFR#48, and took it apart to see the cause of the engine failure.
One of the valves on the exhaust side of piston #8 has broken off the valve stem. As you can see from the picture below, it broke clean off. The rest of the damage is the valve head getting smashed around by the piston, then traveling in cylinder #4 to do some more damage there. The good thing is there are no signs of detonation (tune related), or signs of excessive heat. It was just a part that failed.
Piston #8 damage:
Piston #4 slight damage:
Drivers side head:
Passenger side head:
Already picked up the replacement engine from a local junkyard, out of a 2013 F150 with 27K miles.
New to me engine will be installed by early May, to make the next NASA race back at NJMP May 2/22 weekend.