Disastrous First Drive - V8 Alpina B7: Project Chicago: Part 7 (Patreon)

Well, the saga continues. Don't read further if you don't want spoilers.

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What was supposed to be a pleasant first drive and a beautiful day, turned into a disaster.
I covered around 100 km with the car and everything was going swimmingly, up until it didn't. 

I noticed a knocking sound from the engine and I stopped to assess the situation and called a tow truck. Unfortunately, the engine is dead, again!

I'm yet to pull the engine out and disassemble it, but it's 99% a spun bearing and the rod be knocking on heaven's door right now. The oil filter is full of metal shavings. 

What the hell happened? I've been asking myself the same question and I have no theories.
All of the clearances were within spec and I was so careful when putting it together, I just can't see a reason why it would spin a bearing after just 100 km.

Maybe I messed up during assembly? It's possible, I'm going through everything in my head and can't come to terms with it. 

Anyway, it's not the end of the world as everything is fixable, the question is how bad the damage is and what was the cause. I'll be checking the compression of the engine and scoping the cylinders first. Then everything will come out again for inspection. 

I'll give you an update when I have some answers. Cheers!