Trying to take apart my bmw n51 motor for fun and not trying to rebuild it becuase it toast. Took evetthing atchatchet to block off and finaly got the cylinder head off. The big end bearing is exposed on the pistons on the bottom of the block, i see the bolts that are on the bearings and bolts sorounding the pistons but i dont understand how i will get each one free from block. Any help?

  • What are "bolts surrounding the pistons?" A picture would help. Jun 9, 2018 at 18:53
  • I'll add that if the block is turned over (so the crankshaft is up), then removing the big end bearing caps should result if your being able to withdraw the crankshaft upward from the block, taking the conrods and pistons with it. Jun 9, 2018 at 18:54

1 Answer 1


I am confused by your description of the internals.

However, if this is a “normal” engine then the connecting rod for the piston is fixed to the crankshaft with the big end and cap . Remove the cap and the push the piston out the top of the block.

There were some engines where the pistons came out the bottom of the block but engines are built smaller now so that is hardly likely.

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