Upper or secondary timing chain tensioner for all TVR Speed 6 engines. This is the large plastic tensioner for the upper timing chain in the TVR Speed 6 engine. This is also a direct replacement for the earlier welded shoe type tensioner which is now obsolete. Upper timing chain tension is adjusted via the adjusting shaft just below the cam cover on the front upper righthand side of the TVR Speed 6 engine timing chain cover. It is essential that the timing chain tensions are adjusted whilst the engine is hot due to the differential in expansion coefficients between the aluminium block and steel timing chain.