Nikasil
From Wikipedia, the free encyclopedia
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 pistons 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.
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,Honda 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, causing costly engine failures. Eventually, the product was abandoned after BMW was forced to replace a number of M60 V8 engines in the USA and the UK. Nikasil or similar coatings under other trademarks are still widely used in racing engines where low quality gasoline isn't a problem, this include F1, ChampCar and NASCAR engines.
Engines using Nikasil include:
- Porsche 912 engine ( engine in 917 car, not to be confused with the Porsche 912 car )
- Porsche 911 1973+ (excluding some 1975-1978 911S)
- BMW M60 V8
- BMW M52 I6
- Jaguar AJ-V8
- Maserati Biturbo 2.0 V6 Engines
- Ferrari F50 V12
- Honda XR650R
- Moto Guzzi 850 T3 and derived engines
- BMW R80GS, as measure to reduce weight over cast-iron lined cylinders
- Lambretta TS1
- Honda H-series
- Citroën Visa twin
- Citroën GS birotor wankel engine made by Comotor
