Special nut for Speed 6 engines. This M8 x 1.25mm nut is used in 2 locations on the TVR Speed 6 head. Their primary role is to secure the cam carrier caps and these clever self clinching nuts are chosen for their superior resistance to vibration loosening. As well as their ability to perform long hours of strenuous operation, a major asset is that when loosened during service, they leave the stud in situ (other self locking nuts will tend to undo the stud and nut together) making the job that bit easier. They are also used to secure the cam cover in the vicinity on the spark plugs under the HT alloy cover (the latter also applys to the FFF head). There are 28 are used on the cam carrier caps and 6 used in the cam carrier centre fixings.