• BMW S55 short block from above with pistons installed
  • BMW S55 short block, three-quarter view of the deck
  • Block deck and pistons, close-up
  • Block deck and pistons, close-up
  • Block deck and pistons, close-up
  • BMW S55 short block on the engine stand
  • End view of the S55 block
  • End view of the S55 block
  • Underside of the short block: crankshaft and connecting rods
  • Connecting rod cap, close-up
  • Underside of the short block: crankshaft and main caps
  • Connecting rod and main cap, close-up
  • Block detail, close-up
  • Lang Racing Development crank hub on the crankshaft nose
  • Underside of the short block: crankshaft, rods and main caps
  • Build sheet page 1: components and bearing clearances
  • Build sheet page 2: crank runout, piston-to-wall, ring gaps and rod side clearance
  • Build sheet page 3: deck height, head gasket and squish
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Lang Racing

BMW S55 Stage 1 Built Short Block (Assembled Bottom End)

$13,722.00 USD
$13,722.00 USD

One assembled unit, in stock and ready to ship.

This is a complete BMW S55 short block, built and measured in our Lake Forest, California shop. It's the Stage 1 build from our Built S55 Engine Guide: CP forged pistons and Carrillo connecting rods on the factory crankshaft, with our keyed crank hub fitted. If you want forged internals without waiting on parts, machining and assembly, this is the shortcut.

What's included

Only the parts listed above are included. The cylinder head, head gasket, head studs, timing components, oil pump and oil pan are not.

Measured and documented

Every measurement is on the three-page build sheet in the photos. The highlights:

  • Main bearing clearance: 0.0023–0.0025"
  • Rod bearing clearance: 0.0026–0.0028"
  • Piston-to-wall clearance: 0.0050–0.0055"
  • Ring end gaps: top 0.019", second 0.028–0.029"
  • Rod side clearance: 0.007–0.009"
  • Crankshaft runout 0.0006", end play 0.006"

The main bearing and piston-to-wall clearances run a little looser than BMW's factory numbers on purpose. Our guide explains why.

Head gasket

The pistons sit 0.004–0.006" above the block deck, so use the OEM BMW 1.20 mm head gasket (BMW 11127849620) or thicker. With the 1.20 mm gasket, squish measures 0.041–0.043".

Fits

BMW S55: F80 M3, F82/F83 M4 and F87 M2 Competition.

Finish the engine

Shipping and terms

  • Ships crated by freight from Lake Forest, California, to the lower 48 states: $550 flat, crate included.
  • One unit available. Want one built to your spec? Call us.
  • All sales final. This is a one-off assembled unit, sold as documented in its build sheet.

Questions about fitment, or what else you'll need? Call us at 949-667-4397.