BMW S14 2.3L Engine – US-Spec 1988 E30 M3

Offered here is a BMW S14 2.3-liter inline-four engine removed from a US-spec 1988 BMW E30 M3, owned by the seller for approximately ten years. The S14 represents one of BMW Motorsport’s most legendary naturally aspirated engines, derived from the M10 block and refined with M88/M1 cylinder head technology.

In 2018, the engine underwent comprehensive mechanical refurbishment by Motor Works of National City, California. The rebuild included crankshaft polishing, main bearing saddle honing, connecting rod reconditioning, oil pan repair, and replacement of the timing chain, guide rails, oil pump chain, main bearings, connecting rod bearings, and piston rings.

This engine is configured as a long block with a throttle body assembly installed and includes multiple high-value components, making it an ideal choice for a full E30 M3 restoration or period-correct motorsport build.

Technical Specifications

• Engine Code: S14B23

• Displacement: 2.3 liters (2,302 cc)

• Configuration: Inline-four (I4)

• Valvetrain: DOHC, 16 valves

• Block Material: Cast iron

• Cylinder Head: Aluminum

• Induction System: Individual throttle bodies with “BMW M Power” intake plenum

• Fuel System: Bosch Motronic electronic fuel injection

• Factory Output:

  • 192 hp @ 6,750 rpm

  • 170 lb-ft @ 4,750 rpm

Rebuild Work Performed (2018)

• Crankshaft polished

• Main bearing saddles honed

• Connecting rods reconditioned

• Oil pan repaired

• New timing chain and guide installed

• Oil pump chain replaced

• New main bearings, connecting rod bearings, and piston rings fitted

Included Components

Installed on Engine:

• Throttle body assembly

• Flywheel

• Crankshaft pulley

• Oil filter housing

• Oil pan

• “BMW M Power” valve cover

Included Separately:

• Bosch Motronic ECU (Part no. 0261200071)

• Complete engine wiring harness with sensors

• Aluminum engine mount brackets

• Air filter housing & air flow meter

• Idle control valve

• Remanufactured Bosch starter

• Water pump

• Coolant manifold

• Thermostat and housing

• Mishimoto aluminum radiator

Condition

• Professionally serviced and partially rebuilt in 2018

• Has not been installed or run since rebuild

• Mechanically refreshed long block with ancillary components included

• Ideal candidate for restoration or E30 M3 project reinstallation

Compatibility

• Direct fit: BMW E30 M3 (1986–1991)

• Possible swap candidates: BMW 2002, E21, E28, or E36 projects (with adaptation)