Editing Overhead camshaft engine (section)

== Components ==
=== Timing belt / timing chain ===
{{Main|Timing belt (camshaft)}}
[[File:Replacing a timing belt.jpg|thumb|upright=0.8 |Rubber timing belt during installation]]
The rotation of a camshaft is driven by a [[crankshaft]]. Many 21st century engines use a toothed ''timing belt'' made from rubber and kevlar to drive the camshaft.<ref name=Hillier/><ref name=dansmc.com>{{cite web|url=http://www.dansmc.com/camchain.htm|title=Dan's motorcycle 'Cam Drives'|website=www.dansmc.com|access-date=29 August 2012}}</ref> Timing belts are inexpensive, produce minimal noise and have no need for lubrication.<ref name="Decker">{{Cite journal|last= Decker|first= John|title= Saturday Mechanic: Replacing Your Timing Belt|journal=[[Popular Mechanics]]|date= June 1993|volume=  170|issue=  6|issn= 0032-4558|url= {{Google books|JOQDAAAAMBAJ|Popular Mechanics Jun 1993|page=93|plainurl=yes}}|access-date=1 March 2015|editor-last= Oldham|editor-first= Joe|publisher= Hearst|location= New York, NY US}}</ref>{{refpage|page=93}} A disadvantage of timing belts is the need for regular replacement of the belt;<ref name="Decker"/>{{refpage|page=94}} recommended belt life typically varies between approximately {{convert|50000|-|100000|km|mi|abbr=on}}.<ref name="Decker"/>{{refpage|pages=94-95}}<ref name="Dorries">{{Cite book|last= Dorries|first= Elisabeth H.|title= TechOne: Automotive Engine Repair |url= {{Google books|KsYFA0skuZ8C|TechOne: Automotive Engine Repair|page=250|plainurl=yes}}|access-date= 1 March 2015|publisher= Thompson Delmar Learning|location= Clifton Park, NY US|year= 2005|isbn= 1-4018-5941-0|lccn= 2004057974}}</ref>{{refpage|page=250}} If the timing belt is not replaced in time and fails and the engine is an [[interference engine]], major engine damage is possible.

The first known automotive application of timing belts to drive overhead camshafts was the 1953 [[Bill_Devin#Devin_Enterprises|Devin-Panhard]] racing specials built for the SCCA H-modified racing series in the United States.<ref name="Pace&Brinker">{{cite book|last1= Pace|first1= Harold W.|last2= Brinker|first2= Mark R.|title= Vintage American Road Racing Cars 1950-1969|year= 2004|page= 62|publisher= MotorBooks International|location= St. Paul MN US|isbn= 0-7603-1783-6|url={{Google books|oZempfWXoe4C|Vintage American Road Racing Cars 1950-1969 |plainurl=yes}}|access-date= 27 February 2015}}</ref>{{refpage|page=62}} These engines were based on Panhard OHV flat-twin engines, which were converted to SOHC engines using components from Norton motorcycle engines.<ref name="Pace&Brinker"/>{{refpage|page=62}} The first production car to use a timing belt was the 1962 [[Glas 1004]] compact coupe.<ref>{{cite book |last=Norbye |first=Jan P. |title=BMW - Bavaria's Driving Machines |year=1984 |publisher=Publications International |location=Skokie, IL |isbn=0-517-42464-9 |chapter=Expanding on Excellence: The 5-Series and 3-Series |page=[https://archive.org/details/bmwbavariasdrivi00norb/page/191 191] |chapter-url-access=registration |chapter-url=https://archive.org/details/bmwbavariasdrivi00norb/page/191 }}</ref>

Another camshaft drive method commonly used on modern engines is a ''timing chain'', constructed from one or two rows of metal [[roller chains]].<ref name=Hillier/><ref name=dansmc.com/> By the early 1960s most production automobile overhead camshaft designs used chains to drive the camshaft(s).<ref name="Boddy">{{cite journal|last=Boddy |first=William |author-link= Bill Boddy |url=https://www.motorsportmagazine.com/archive/article/january-1964/17/random-thoughts-about-ohc|title= Random Thoughts About O.H.C. |journal= [[Motor Sport (magazine)|Motor Sport]]|date= January 1964 |volume= XL|issue= 1|publisher= Teesdale Publishing|location= London, UK}}</ref>{{refpage|page=17}} Timing chains do not usually require replacement at regular intervals, however the disadvantage is that they are noisier than timing belts.<ref name="Dorries"/>{{refpage|page=253}}

===Gear train===
A [[gear train]] system between the crankshaft and the camshaft is commonly used in diesel overhead camshaft engines used in heavy trucks.<ref>{{cite book|last= Bennett|first= Sean|title= Modern Diesel Technology: Diesel Engines|pages= 88–89, 362|publisher= Cengage Learning|location= Stamford, CT US|isbn= 978-1-285-44296-9|url={{Google books|8OzKAgAAQBAJ|Modern Diesel Technology: Diesel Engines|page=88|plainurl=yes}}|access-date= 4 January 2015|quote= In most commercial diesels, OHCs are gear-driven.|date= 2014-01-01}}</ref> Gear trains are not commonly used in engines for light trucks or automobiles.<ref name=Hillier/>

=== Other camshaft drive systems ===
[[File:Norton No66, pic-003.JPG|thumb|Norton motorcycle engine with a [[bevel gear|bevel]] shaft-driven camshaft]]

Several OHC engines up until the 1950s used a shaft with [[bevel gear]]s to drive the camshaft. Examples include the 1908–1911 [[Maudslay Motor Company|Maudslay 25/30]],<ref>{{cite journal|last= Boddy|first= William|author-link= Bill Boddy|title= An Edwardian Overhead-Camshaft 25/30 Maudslay|journal= [[Motor Sport (magazine)|Motor Sport]]|page= 909|url= http://www.motorsportmagazine.com/archive/article/august-1972/68/edwardian-overhead-camshaft-2530-maudslay|access-date= 6 February 2015|date= August 1972|volume= XLVIII|issue= 8|editor-last= Boddy|editor-first= William|publisher= Teesdale Publishing|location= London, UK|url-status= live|archive-url= https://web.archive.org/web/20150206033639/http://www.motorsportmagazine.com/archive/article/august-1972/68/edwardian-overhead-camshaft-2530-maudslay|archive-date= 6 February 2015}}</ref><ref name="Culshaw">{{cite book |last1= Culshaw|first1= David|last2= Horrobin|first2= Peter|year= 2013|orig-year= 1974|chapter= Maudslay|title= The Complete Catalogue of British Cars 1895 - 1975|edition= e-book|location= Poundbury, Dorchester, UK|publisher= Veloce Publishing|page= 210|isbn= 978-1-845845-83-4}}</ref> the [[Bentley 3 Litre]],<ref>{{Cite book|last= Norbye|first= Jan P.|title= The complete handbook of automotive power trains|page= 318|publisher= Tab Books|year= 1981|isbn= 0-8306-2069-9|lccn= 79026958|url= {{Google books|YSpKEyATeM8C|The complete handbook of automotive power trains|page=318|plainurl=yes}}|access-date= 7 January 2015}}</ref> the 1917-? [[Liberty L-12]],<ref>{{Cite web|url=https://books.google.com/books?id=hylFAQAAIAAJ&pg=RA4-PA67|title=The Bulletin of the Airplane Engineering Department, U.S.A.|first=United States Bureau of Aircraft Production Airplane Engineering|last=Department|date=March 4, 1918|publisher=War Department, Bureau of Aircraft Production, Airplane Engineering Department|via=Google Books}}</ref> the 1929-1932 [[MG M-type|MG Midget]], the 1925-1948 [[Velocette#Velocette 'K' series|Velocette K series]],<ref>{{Cite journal|last= Cameron|first= Kevin|author-link= Kevin Cameron (journalist)|title= TDC: Little things|journal= [[Cycle World]]|date= March 2004|volume= 43|issue= 3|issn= 0011-4286|page= 14|url= {{Google books|VYB28ExdkSMC|Cycle World Magazine Jan 2004|page=RA2-PA22|plainurl=yes}}|access-date=7 January 2015}}</ref> the 1931-1957 [[Norton International]] and the 1947-1962 [[Norton Manx]].<ref>{{cite book|last= Wilson|first= Hugo|title= The Encyclopedia of the Motorcycle|url= https://archive.org/details/encyclopediaofmo00wils_1|url-access= registration|year= 1995|publisher= Dorling Kindersley|location= London, UK|isbn= 0-7513-0206-6|page= [https://archive.org/details/encyclopediaofmo00wils_1/page/144 144]|chapter= The A-Z of Motorcycles}}</ref> In more recent times, the 1950-1974 [[Ducati singles|Ducati Single]],<ref>{{cite book|last= Walker|first= Mick|author-link= Mick Walker (motorcycling)|title= Ducati Singles Restoration|chapter= 4 Engine|page= 48|year= 2003|orig-year= 1991|publisher= Motorbooks International|location= St. Paul, MN US|isbn= 0-7603-1734-8|url= {{Google books|JaXQtjcbmC4C|Ducati Singles Restoration|page=48|plainurl=yes}}|access-date= 4 January 2015|chapter-url={{Google books|JaXQtjcbmC4C|Ducati Singles Restoration|page=32|plainurl=yes}}}}</ref> 1973-1980 [[Ducati L-twin engine]], 1999-2007 [[Kawasaki W650]] and 2011-2016 [[Kawasaki W800]] motorcycle engines have used bevel shafts.<ref>{{Cite web|url=http://www.kawasaki.eu/en/products/sports/2015/w800_/overview?Uid=096BDlgLWQ0JWAldClhcXAsMWwoMCVlcXgteXwoLC1BaUQw|title= 2015 W800|website=www.kawasaki.eu |access-date=19 December 2019}}</ref><ref>{{cite news|last= Ash|first= Kevin|author-link= Kevin Ash|title= Kawasaki W800 review|newspaper= [[The Daily Telegraph|The Telegraph]]|date= 26 October 2011|url= https://www.telegraph.co.uk/motoring/motorbikes/8833767/Kawasaki-W800-review.html|url-status= live|archive-url= https://web.archive.org/web/20130621065158/http://www.telegraph.co.uk/motoring/motorbikes/8833767/Kawasaki-W800-review.html|archive-date=21 June 2013}}</ref> The [[Crosley]] four cylinder was the last automotive engine to use the shaft tower design to drive the camshaft, from 1946 to 1952; the rights to the Crosley engine format were bought by a few different companies, including [[General Tire]] in 1952, followed by [[Fageol]] in 1955, Crofton in 1959, [[Homelite]] in 1961, and [[Fisher Pierce]] in 1966, after Crosley closed the automotive factory doors, and they continued to produce the same engine for several more years.

A camshaft drive using three sets of cranks and rods in parallel was used in the 1920–1923 [[Leyland Eight]] luxury car built in the United Kingdom.<ref>{{ cite patent | country = US | number = 1495620 A | status = patent | title = Internal Combustion Engine | pubdate =  | gdate = 1924-05-27 | fdate = 1921-03-15 | pridate =  | inventor =John Godfrey Parry Thomas | assign1 =  | assign2 =  | class = |ref=none }}</ref><ref>{{US patent|1495620}}</ref><ref name="WBMarch74">{{cite journal|title= How Did The Leyland Eight Rate?|last= Boddy|first= William|author-link= Bill Boddy|page= 230|journal= [[Motor Sport (magazine)|Motor Sport]]|volume= L|issue= 3|editor-last= Boddy|editor-first= William|date= March 1974|url= https://www.motorsportmagazine.com/archive/article/march-1974/38/how-did-leyland-eight-rate|access-date= 3 January 2015}}</ref> A similar system was used in the 1926-1930 [[Bentley Speed Six]] and the 1930-1932 [[Bentley 8 Litre]].<ref name="WBMarch74" /><ref>{{cite journal | last1 = Brooks | first1 = Philip C.  | editor1-last =  Carpenter | editor1-first = Rhonda | editor2-last = Iwalani | editor2-first = Kahikina | year = 2009 | title = The Mighty Sixes | journal = The International Club for Rolls-Royce & Bentley Owners Desk Diary 2010 | pages = 27, 32 | location = Tampa, FL USA | publisher = Faircount }}</ref> A two-rod system with counterweights at both ends was used by many models of the 1958-1973 [[NSU Prinz]].<ref name="Boddy"/>{{refpage|page=16-18}}
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