Aston Martin RB6 engine
{{Use dmy dates|date=April 2022}}
{{Infobox automobile engine
|name=Aston Martin RB6
|manufacturer={{flagicon|UK}} Aston Martin
|production=1959–1960
|configuration=95° I-6, naturally-aspirated
|displacement={{convert|2.5|L|cuin|0|lk=on|abbr=on}}
|bore={{convert|83|mm|in|1|lk=on|abbr=on}}
|stroke={{convert|90|mm|in|1|lk=on|abbr=on}}
|valvetrain=24-valve, DOHC, four-valves per cylinder
|power={{convert|250-280|hp|kW|0|lk=on|abbr=on}}
|torque= {{convert|208-235|lbft|Nm|0|lk=on|abbr=on}}
|lubrication=Dry sump
|fuelsystem=Carburetor
|oilsystem=Dry sump
|weight={{convert|203|kg|lb|0|lk=on|abbr=on}}
}}
The Aston Martin RB6 is a 2.5-litre, naturally-aspirated, inline-6 racing engine, developed and designed by Aston Martin for Formula One racing; used between {{F1|1959}} and {{F1|1960}}.{{cite web|url=https://www.statsf1.com/en/moteur-aston-martin.aspx |title=Engine Aston Martin • STATS F1 |publisher=Statsf1.com |date= |accessdate=2021-11-05}} The RB6 also shared the basic double-overhead camshaft straight-6 Aston Martin engine design with its brethren, but sleeved to reduce its capacity to 2.5-litres. Although Tadek Marek's design was a reliable and powerful unit in its 3.7-litre road car form, the reduced capacity racing motor was hard-pressed to cope with the heavy chassis and poor aerodynamics, and frequent engine failures blighted the DBR4's brief racing career. Aston Martin claimed a {{convert|280|bhp|kW|-1|abbr=on}} output for the DBR4's engine. However, it was common practice at the time to overquote engine power, and a more realistic value is closer to {{convert|250|bhp|kW|-1|abbr=on}}. This value is still higher than that provided by the Coventry Climax FPF straight-4, used by contemporary manufacturers such as Lotus and Cooper, but the Aston Martin engine weighed appreciably more. The engine drove the rear wheels through a proprietary David Brown gearbox, provided by Aston Martin's owners.{{Cite web|url=https://www.bonhams.com/auctions/21906/lot/316/|title = Bonhams : 1959 Aston Martin DBR4/250 Formula 1 Monoposto Re-creation Engine no. RB6/2501}}{{cite web|last=Patrice |first=Minol |url=https://petrolicious.com/articles/the-aston-martin-dbr4-wasnt-an-f1-champion-but-this-particular-chassis-still-has-a-story |title=The DBR4 Wasn't An F1 Champion, But This Particular Aston Chassis Still Has A Story To Tell • Petrolicious |publisher=Petrolicious.com |date=2018-05-28 |accessdate=2021-11-05}}{{cite web |url=https://www.astonmartin.com/en/our-world/amf1/history |title=A journey through Aston Martin's Grand Prix heritage |publisher=Aston Martin |date= |accessdate=2021-11-05 |archive-date=21 October 2021 |archive-url=https://web.archive.org/web/20211021093858/https://www.astonmartin.com/en/our-world/amf1/history |url-status=dead }}
The DBR5's engine was smaller and lighter. The new engine modifications meant that the power output was finally close to the figure originally claimed by the Aston Martin workshop.{{Cite web|url=https://memim.com/aston-martin-dbr4.html|title = Aston Martin DBR4}}{{cite web|url=https://www.ultimatecarpage.com/car/17/Aston-Martin-DBR4.html |title=1959 Aston Martin DBR4 - Images, Specifications and Information |publisher=Ultimatecarpage.com |date=2016-03-18 |accessdate=2021-11-05}}{{cite web|author=2 min read |url=https://www.supercars.net/blog/1957-aston-martin-dbr4/ |title=1957 Aston Martin DBR4 | Aston Martin |publisher=SuperCars.net |date=1970-01-01 |accessdate=2021-11-05}}{{Cite web|url=https://www.goodwood.com/grr/race/historic/2021/2/the-forgotten-aston-martin-f1-car--thank-frankel-its-friday/|title = The forgotten Aston Martin F1 car | Thank Frankel it's Friday | GRR}}{{cite web|url=https://pendine.com/cars-for-sale/1959-aston-martin-dbr4/ |title=1959 Aston Martin DBR4 » Pendine Historic Cars |publisher=Pendine.com |date=1984-10-14 |accessdate=2021-11-05}}