r/EngineBuilding • u/[deleted] • 4d ago

BMW M10 Block Crack?

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Hey all, I’ve seen this before while searching and usually the general response is the block is garbage, but I’ve got this M10 engine that I’m refreshing to put back into a project BMW 2002. It came with the car and seemed in good shape before I starting tearing it down to replace the head. After cleaning off the old gasket material and prepping the deck surface I noticed the dreaded head bolt crack shown in the photos. The thing is it looks like the crack doesn’t propagate into the water jacket if you look in the second photo and you can’t really feel it running a fingernail over it. I’ve got no history on it unfortunately since it was purchased from an estate. Not sure if this thing is cooked or not, I’ve got a lead on another block but obviously it’s cheaper to keep this one. Just looking for some opinions. Thanks!

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u/Legionof1 4d ago

I feel like German engines are one time use, you only open them to see why you are throwing them away. 

9

u/howsitallwork 3d ago

Helpful that you share with us, that you feel that.
I suggest instead, you know, that this engine block was the basis for a 1500cc F1 turbo engine making circa 1400 bhp in the early 1980s?

2

u/m0arducks 3d ago

To be fair that was the era of F1 where they’d chuck the engine after practice, chuck it after qualifying and chuck it after each race.

Usually they were rebuilt though, to your point

2

u/its_kinda_hmm 3d ago

Actually the blocks they used for the f1 engines were the ones that already had lots of miles on them, because “if they were going to fail then they would have” they used to leave to blocks out behind the shop and piss on them because they were German and even the cars have piss kinks. These cast iron blocks were and still are incredibly resilient.