Thanks to Brett Anderson at Koala Motorsports for this page.

The M60 3.0 and 4.0 liter V8's were introduced by BMW in 1993, installed in the 5,7 and 8 series models. In 1996 they were replaced by the M62 4.4 liter V8, with BMW dropping the 3.0 liter engine in the US. Outside of the US, vehicles received the M62 3.5 liter V8's. The early production M60 engines were made of Nikasil, an aluminum impregnated with Nickel and Silicone. The Nikasil blocks reacted adversely to the sulfur content in fuel found in some parts of the US, causing pitting in the top few millimeters of the cylinders. Blemishes on the cylinder wall prevents proper sealing of the piston rings, causing excessive leak down (the amount of air that escapes past the piston as it attempts to compress that air into the combustion chamber). Valves that don't seal properly can also cause leak down.

The M60 engines that have extreme leak down suffer a very rough idle. With the performance profile of the cams in this engine, a slight rock at idle is normal. Because of the problems with the early M60 V8's, BMW extended their warranty on these engines to 100,000 miles or six years. If you feel that your engine idles too rough, make an appointment with your local dealer for an idle quality check. This service is free of charge. So is the replacement of a defective short block if within the warranty period. The later production M60 and all M62 engines are made of Alusil, the same compound proven in the V12 engine. Alusil blocks are not effected by fuels with sulfur contents. Below is a list of casting numbers of M60 blocks using the two compounds.

Nikasil M60B30     1 725 970  or  1 741 212

Nikasil M60B40     1 725 963  or  1 742 998

Alusil M60B30       1 745 871

Alusil M60B40       1 745 872