model: 728i/728iL 2.8L
engine: M52B28 Petrol I6
year: 1996-2001

The BMW M52 is a Straight 6 piston engine. Displacement ranges from 2000 cc to 3200 cc. It is a DOHC 24-valve engine, originally introduced with with VANOS Variable valve timing. It replaced the BMW M50 engine in 1994 and was replaced in 2001 with the BMW M54 Nikasil lined aluminium cylinders instead of a cast iron cylinder block, resulting in lighter engines. While, the American market engine retained its cast iron block due to the sulfur content of available fuel.

In markets with low-sulfur fuel this engine was very highly regarded and the M52 was on the Ward's 10 Best Engines list for 1995 through to 1998. However, there was criticism of the M52 engine in some markets, especially the UK, which had high levels of sulfur in the petrol during the late 90's. Sulfur acts as a corrosive agent against Nikasil and led to a lot of the early engines having premature bore-liner wear. Fortunately this problem was solved in post-September 1998 cars with the introduction of steel cylinder liners, with the designation M52 TU-3. However problems still present in these engines so affected cars of this period should be bought with caution unless the service history verifies that work was carried out to rectify the problem. The American market M52 used a cast iron block, and so, was unaffected by this problem.

M52 modifications:

Engine	Displacement	Power	Torque	Redline	Year	Stroke	Bore	Compression
M52B20	2.0 L (1991 cc/121 in³)	110 kW (148 hp) @ 5900	190 N·m (140 ft·lb) @ 4200	6500	1994	66 mm (2.6in)	80 mm (3.15in)	11.0:1
M52TUB20		110 kW (148 hp) @ 5900	190 N·m (140 ft·lb) @ 3500	6500	1998	66 mm (2.6in)	80 mm (3.15in)	11.0:1
M54B22	2.2 L	125 kW (168 hp)	210 N·m (155 ft·lb)	6500	2000
M52TUB24	2.4 L (2394 cc/146 in³)	135 kW (184 hp) @ 5800	240 N·m (177 ft·lb) @ 3600	6500	2000
M52B25	2.5 L (2494 cc/152 in³)	123 kW (170 hp) @ 5500	245 N·m (181 ft·lb) @ 3950	6500	1995
M52TUB25		123 kW (170 hp) @ 5500	245 N·m (181 ft·lb) @ 3500	6500	1998	75 mm (2.95in)	84 mm (3.31in)	10.5:1
M52B28	2.8 L (2793 cc/170 in³)	142 kW (190 hp) @ 5300	280 N·m (207 ft·lb) @ 3950	6500	1995	84 mm (3.31in)	84 mm (3.31in)	10.2:1
		141 kW (189 hp) @ 5300	275 N·m (203 ft·lb) @ 3950	6500	1997
M52TUB28		142 kW (193 hp) @ 5500	280 N·m (207 ft·lb) @ 3500	6500	1998