Nikasil is a trademarked electrodeposited oleophilic nickel matrix silicium carbide coating for engine components, mainly piston engine cylinder liners. It was introduced by Mahle in 1967, initially developed to allow rotary engine apex seals (NSU Ro80 and C111) to work directly against the aluminum housing. This coating allowed aluminium cylinders and pistons to work directly against each other with low wear and friction. Unlike other methods, including cast iron cylinder liners, Nikasil allowed very large cylinder bores with tight tolerances and thus allowed existing engine designs to be expanded easily, the aluminium cylinders also gave a much better heat conductivity than cast iron liners which is an important factor for a high output engine. The coating was further developed by US Chrome Corporation in the USA in the early 1990s (under the trade name of "Nicom") as a replacement for hard-chrome plated cylinder bores for Mecury Marine Racing, Kohler Engines, and as a repair replacement for factory-chromed snowmobiles, dirt bikes, ATVs, watercraft and automotive V8 liners/bores.
Porsche started using this on the 1970 917 race car, and later on the 1973 911 RS. Porsche also used it on production cars, but for a short time switched to Alusil due to cost savings for their base 911. Nikasil cylinders were always used for the 911 Turbo and RS models. Nikasil coated aluminum cylinders allowed Porsche to build air-cooled engines that had the highest specific output of any engine of their time. Nikasil is still used in today's 911s with great success.
Nikasil was very popular in the 1990s. It was used by companies such as BMW, Ferrari and Jaguar Cars in their new engine families. However, the sulfur found in much of the world's low quality gasoline caused the Nikasil cylinders used by BMW to break down over time [1], causing costly engine failures. BMW eventually abandoned its Nikasil coating after replacing a number of M60 V8 engines in the USA and the UK.
Nikasil or similar coatings under other trademarks are also still widely used in racing engines, including those used in Formula One and ChampCar.
but like the cougar no-one knows how to fix the engines and service cost are high. This is why you can pick up a 750i or 850 for about ?ú10k or less nowadays.
