Editing Triumph slant-four engine (section)

==Sprint 16-valve engine==
[[File:Dolomite Sprint Valves Section.jpg|thumb|left|Cross-section of Dolomite Sprint cylinder head, highlighting the single cam operating both inlet and exhaust.]]
[[File:1974 Triumph Dolomite Sprint - Flickr - The Car Spy (21).jpg|thumb|Triumph Dolomite Sprint engine]]
Triumph added a unique [[multi-valve|16-valve]] [[cylinder head]] to the slant-four for the 1973 [[Triumph Dolomite|Dolomite Sprint]]. At the time there were at [[British Leyland]] (BL) both [[Harry Mundy]], who worked on engine development at Jaguar, and [[Walter Hassan]], also at Jaguar but in charge of engine technology development at BL as well. These two shared data on four-valve cylinder heads with King.<ref name="valebook"/>{{rp|55, 56}} 

A team of engineers led by King and "with co-operation from [[Harry Mundy]] and the engineers at [[Coventry Climax]]",<ref name="aronline"/> developed a 4-valve-per-[[Cylinder (engine)|cylinder]] head where all of the valves are actuated by a single [[camshaft]] rather than the more conventional [[Overhead camshaft#Dual overhead camshaft|DOHC]] arrangement. The valves are arranged in two rows of eight, inclined 27° from vertical. The inlet valves are {{cvt|1.38|in|mm|2}} in diameter and are operated by the camshaft lobes through bucket tappets, while the exhaust valves are {{cvt|1.21|in|mm|2}} in diameter and are operated through rocker arms.<ref name="valebook"/>{{rp|58, 59}} The design of the cylinder head won a British [[Design Council]] award in 1974.<ref name="vads.ahds.ac.uk"/>

Capacity was increased to {{cvt|1998|cc|cuin|0}}, and larger HS6 [[SU carburettor]]s were fitted. Other changes to the Sprint engine included a duplex timing chain and alloy timing cover.<ref name="valebook"/>{{rp|49, 60}} The big-end journals were also cross-drilled.<ref name="autocar26jul73"/>

The engine was expected to make 135&nbsp;bhp,<ref name="cmm-aug1995"/> and King returned from holiday "to find an engine running on the bed giving 150&nbsp;bhp at the first build."<ref name="autocar21jun73"/> Hence, it was initially intended to be named the 'Dolomite 135'. This was changed to 'Dolomite Sprint' and published reasons vary. One oft-repeated rumour is that production lines could not guarantee 135&nbsp;bhp. However according to Matthew Vale,<ref name="valebook"/> it was during development that Triumph switched to measuring power from imperial (SAE) to metric (DIN), which calculated outputs approximately 5% lower. In this case 135&nbsp;bhp SAE is 127&nbsp;bhp DIN.<ref name="valebook"/>{{rp|103}}

The Dolomite Sprint has been described as "the world's first mass-produced multi-valve car".<ref name="gerard2010"/> Multi-valve engines had first appeared in 1912, with the most recent prior to the release of the Sprint engine being the [[Cosworth BDA]] and  [[Nissan S20 engine|Nissan S20]] (1969) and [[Lotus 907]] (1972), but they had not been not used in mass-production vehicles until after the introduction of the Dolomite Sprint.

The 16-valve 2.0&nbsp;L engine was also used in a small number of prototype and pre-production [[Triumph TR7 Sprint|TR7 Sprint]]s built at Triumph's plant in [[Speke]] during 1977.<ref name="piggottbook"/>

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