JAGUAR V-8 ENGINES WITH NIKASIL CYLINDERS
By Roy Cleveland
There have been instances when early Jaguar V-8 engines with Nikasil coated cylinder have had to be replaced. There have been various references to this in the Jaguar specific magazines originating in the UK but until now, I have not seen entire articles devoted to the subject. The April 2004 edition of the Jaguar Enthusiast and the May 2004 edition of Jaguar World both have good articles on this subject. I will summarize some of the information from those articles here.
Nikasil is a coating that can prevent wear when applied to the cylinder bores of aluminum engines. It allows the engine to be built without the need of steel cylinder liners thus saving both cost and weight.
The Problem – “Several unrelated factors combine to break down the coating and cause a loss of compression, which eventually results in an engine that spins over freely without building up enough compression to start.” (JW)
What Causes the Problem – “Nikasil and sulphur do not go well together. Unfortunately, all gasoline contains some sulphur. The corrosive effects of sulphur are compounded by an injection fault that causes over fuelling if the car is stopped and re-started prior to the end of the warm-up cycle. Similarly, regular short journeys, where the engine fails to warm up fully, will also expose the bores to more sulphur than is good for them.” (JW)
It appears that this problem is confined to 1997-2000 Jaguar V-8 engines with possibly some 2001 engines being affected. Apparently Jaguar switched to steel cylinder liners at some point in 2001. There is some inconsistency between the information contained in the UK articles and information available within the US. The English magazines mentioned above state that the problem is confined to the UK market. It is not believed that this problem is widespread in the US but it has occurred on some US cars.
BMW suffered similar problems with their early V-8s (mid to late 1990s) and information on their problems can be found at www.koalamotorsport.com.
The Jaguar World article says of the Jaguar V-8 engine “The basic layout and design is good, combining power with commendable fuel economy and light weight, and there is no reason to doubt that later versions (particularly the current 4.2 litre) will not match the reputation for reliability enjoyed by the previous AJ6/16 engine family.”
Suffice it to say, if you are considering the purchase of a used Jaguar with a V-8 engine, you would probably want to consider reviewing the service history of the car for indications of recurring starting problems. The English articles say that a test can be performed to determine the amount of compressed air and fuel that is leaking past the piston rings. The articles also mentioned that driving styles could be a factor, i.e., cars driven for longer trips would be at less risk than one driven on lots of short trips and allowed to get cold before restarting. If an engine has been replaced, it is believed that steel cylinder liners are used in factory supplied replacement engines.