I've recently bought myself a project car - 2006 Cooper S with a blown motor (https://www.northamericanmotoring.co...wn-engine.html). As I figured out - the first cylinder's piston disintegrated making a hole in the block and ruining a crankshaft. Fine.
I bought another short block HOPING that the crankshaft there is good. Nope. While the block is fine, the engine had spun rod bearings in... yep, the 1st cylinder as well. The rod journal for the first cyl on that crankshaft is measured as 44.30 mm (with the spec at 46 mm). I.e., the crankshaft is trash as well: the lowest possible value is 45.50 with undersized King bearings (+0.5).
I saw a lot of reports about the blown W11 engines and most (if not all) of them got problems in the 1st cylinder.

So.... Why is it so? Is there an oil supply issue in the first cylinder? Any ideas?

And isn't it the reason, why it is so hard to find used crankshaft for W11? Ebay (US) has NONE, while I see a lot of offers for W10, N12, N14, N16, N18.

 

Intake design and eventual production intake info was posted (post #14) by an Engineer who worked on the development of the engine and referred to issues regarding cylinder #1. ...maybe this is leading to the failures?

https://www.northamericanmotoring.co...ml#post4188398

 

Bank 1 lean condition created due to bad engine management tune on a engine bearing high heat cycles due to forced induction from Supercharger....Why out of the box they run rich....However, some "tuners" will historically go for the Max HP numbers for the feedback but at the cost of leaning out the injectors and bank one more prone than the others some of which due to exhaust / intake manifold design flow.

I have 250K miles on same W11 engine....runs better today than on the day I purchased it.