At least Dan stayed and helped clean up :tongueout:
Thankfully for once it's pretty clear,
The centre main bearing has spun, this then blocks the hole for the oil feed to the crank and the rod on number 2 gets starved of oil and overheats (goes blue) and throws the rod when it's get to a certain temperature which is why the ARP's are blue and sheared.
All the data backs this up with a sudden increase in oil temp as it was trying to quench the overheating bearing.
No obvious sign of a pressure drop in the session to start the bearing spinning but it's a very common failure.
Solution is to tag the main bearing but if the bearing wants to still turn with enough force it will.
Head and cams have survived surprisingly :smile:
Pleased to hear that something can be salvaged.
Out of interest what sample rate are you monitoring oil pressure at?
Regards what caused it, all materials flex to some extent, thats a given, but i'm not sure I'd go along with crank flex being the reason for the bearing spinning.
I've spent a fair bit of time with Subarus and i'm sure most folk know they can be prone to bearing failures. I've read just about every weird and wonderful explanation going as to why they do beairngs in, oil starvation, block flex, crank flex, detonation, design of the oil gallaries the list goes on. The truth is, at this level of motorsport nearly all of the explanations are just best guesses.
In the Subaru scene, as time has gone on and people have learned what they can from the failures, more and more are now running proper motorsport bearings with proper motorpsort clearances and dry sump systems, needless to say it's now possible to maintain far higher levels of reliablity at quite impressive power outputs than was ever thought possible even 4-5 years ago.
My "guess" would be fatigue and or damage to the bearing surfaces as a result of repeated drops in oil pressure through starvation. When the surface of the bearing gets damaged enough that the oil film is compromised, bearing nips onto the crank and spins, tagged or not, it's still going to spin.
Be intersting to see the rest of the crank bearings, my "guess" could be totally wrong but regardless, i'd say you got pretty good service from what was essentially a standard road car engine.