BMW M52B20TU

The BMW M52B20TU is a 2.0 liters (1,991 cc, 121.5 cu-in) straight-six, four-stroke cycle natural aspirated gasoline engine from BMW M52-family. The engine was manufactured on Munich Plant (Munich, Germany) from 1998 to 2000. M52B20TU engine is a technical update (hence the designation TU) of the earlier M52B20 engine. The main “technical update” for M52TU was the addition of double VANOS.

The M52B20 TU engine features a cast-aluminum alloy cylinder block with cast-iron cylinder liners. The aluminum cylinder head uses chain-driven double overhead camshafts (DOHC) and four valves per cylinder (24 valves in total). It is equipped with a Siemens MS 42.0 DME (Digital Motor Electronics) system, double VANOS (Variable Valve Timing System from BMW) for both inlet and exhaust camshafts, Motor Driven Throttle Valve, dual length intake manifold (called “DISA” by BMW) and a distributorless ignition system with individual ignition coils for each cylinder.

Cylinder bore and piston stroke are 80.0 mm (3.15 in) and 66.0 mm (2.6 in), respectively. Compression ratio rating is 11.0: 1. The BMW M52B20 engine produced 150 PS (110 kW; 148 HP) at 5,900 rpm of maximum horsepower and 190 N·m (19.4 kg·m, 140 ft·lb) at 3,500 rpm of peak torque.

The breakdown of the engine code is as follows:

• M52 – Engine Family
• B – Gasoline
• 20 – 2.0 Liter Displacement
• TU – Technical update

General information

Cylinder block

The BMW M52B20TU cylinder block is cast aluminum alloy with cast iron cylinder liners, bore is 80.0 mm (3.15 in) and stroke is 66.0 mm (2.60 in). The cylinders are exposed on all sides to circulating coolant. The counterweighted crankshaft rotates in replaceable split-shell main bearings. This engine used seven main bearings.

The forged steel connecting rods use replaceable split-shell bearings at the crankshaft end and solid bushings at the piston pin end. The pistons are of the three-ring type with two upper compression rings and a lower one-piece oil scraper ring. Full-floating piston pins are retained with circlips. The compression ratio rating is 11.0:1.

Cylinder head

The cylinder head is made of an aluminum alloy with good cooling efficiency. The M52B20TU engine use chain-driven double overhead camshafts and four valves per cylinder. Standart head height is 140.0 mm (5.5118 in). The cylinder head employs a crossflow design for greater power and efficiency. Intake air enters the combustion chamber from one side while exhaust gasses exit from the other. This engine is equipped with double VANOS (Variable Camshaft Timing) system. VANOS is fully variable and operates independently on both intake and exhaust sides.

Intake valves are 30.0 mm (1.1811 in) in diameter and exhaust valves are 27.0 mm (1.063 in), valve lift are 9.0 mm (0.356 in). Intake valves duration is 244°, and exhaust valves duration is 228°. Valve clearance is set by self-adjusting (zero-lash) hydraulic lifters for reduced valve noise and the elimination of routine valve adjustment.

Head tightening procedure and torque specs:

• Step 1: 40.0 Nm; 4.1 kg·m; 29.5 ft·lb
• Step 2: Turn all bolts 90°
• Step 3: Turn all bolts another 90°

Maintenance data

Vehicle applications

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