Honda V12 engine

{{Infobox automobile engine

|image=Honda RA121E engine Honda Collection Hall.jpg

|configuration=1964–1968: 60°-90° V12
1991–1992: 60°-75° V12

|manufacturer={{flagicon|Japan}} Honda

|designer=Yoshio Nakamura (1964-1968)
Osamu Goto (1991-1992)

|production=1964–1968, 1991–1992

|fueltype=Gasoline

|fuelsystem=Carburetor
Electronic fuel injection

|coolingsystem=Water-cooled

|displacement={{ubl

| {{cvt|1495|cc|L|1|order=flip}}

| {{cvt|2993|cc|L|1|order=flip}}

| {{cvt|3493|cc|L|1|order=flip}}

| {{cvt|3498|cc|L|1|order=flip}}

| {{cvt|3496|cc|L|1|order=flip}}

}}

|bore={{ubl

| {{cvt|58.1|mm|in|1}}

| {{cvt|78|mm|in|1}}

| {{cvt|83|mm|in|1}}

| {{cvt|86.5|mm|in|1}}

| {{cvt|88|mm|in|1}}

}}

|stroke={{ubl

| {{cvt|47|mm|in|1}}

| {{cvt|52.2|mm|in|1}}

| {{cvt|53.8|mm|in|1}}

| {{cvt|49.6|mm|in|1}}

| {{cvt|47.9|mm|in|1}}

}}

|valvetrain = 48-valve, DOHC, four-valves per cylinder{{Cite web|url=https://www.auto123.com/en/news/f1-hondas-first-formula-1-engine-almost-50-years-ago-video/35603/|title=F1: Honda's first Formula 1 engine, almost 50 years ago (+video) | Car News | Auto123|website=auto123.com}}{{Cite web|url=https://www.conceptcarz.com/z27340/honda-ra272.aspx|title=1965 Honda RA272|website=conceptcarz.com}}{{Cite web|url=https://primotipo.com/2014/12/12/honda-ra271272-1-5-litre-v12-19645-gp-cars/|title=Honda RA271/272 1.5 Litre V12 1964/5 GP Cars…|date=December 12, 2014}}

|aspiration=naturally-aspirated

|weight={{convert|120-160|kg|lb|1|abbr=on}}{{cite web|url=http://www.f1-forecast.com/pdf/F1-Files/Honda/F1-SP2_02e.pdf|format=PDF|title=Summary of Honda Formula One Engine in Third-Era Activities|website=F1-forecast.com|access-date=10 November 2021}}

|power={{cvt|210-800|PS|kW hp|0}}{{Cite web|url=https://www.statsf1.com/en/moteur-honda.aspx|title = Engine Honda |website=Statsf1.com}}{{Cite web|url=https://global.honda/heritage/episodes/1964formulaoneentry.html|title=Honda Global | Formula One Entry: The Initial Phase / 1964|website=global.honda}}

|torque={{cvt|150-500|Nm|lbft|0}}{{Cite web|url=https://www.f1technical.net/forum/viewtopic.php?t=29523|title=1990's F1 Engine Torque graphs - F1technical.net|website=www.f1technical.net}}{{Cite web|url=https://spicerparts.com/calculators/horsepower-torque-calculator|title = Spicer Horsepower and Torque Calculator|website=spicerparts.com}}

|compression=12.0:1-12.9:1{{Cite web|url=https://www.f1technical.net/forum/viewtopic.php?t=27760&start=240|title=Specifications of 50 famous racing engines up to 1994 - Page 17 - F1technical.net|website=www.f1technical.net}}

|predecessor=Honda RA16 engine

|successor=Honda V10 engine

}}

Honda has made a number of naturally-aspirated V12 engines designed for Formula One motor racing; starting with the 1.5-litre RA271E engine in {{F1|1964}},{{Cite web|url=https://www.roadandtrack.com/motorsports/a29588807/honda-formula-1-v-12-ra272-history/|title = When Honda Brought a 1.5-Liter V-12 to Formula 1|date = 2 October 2020|website=Roadandtrack.com}}{{Cite web|url=https://www.auto123.com/en/news/f1-hondas-first-formula-1-engine-almost-50-years-ago-video/35603/|title = F1: Honda's first Formula 1 engine, almost 50 years ago (+video) | Car News |website=Auto123.com}} and ending with the 3.0-litre RA273E in {{F1|1968}}.{{Cite web|url=https://www.youtube.com/watch?v=Tpym8zNcpxU|title=1967 Honda RA300 F1 Car - 3.0L V12 Engine Sound!|access-date=10 November 2021|publisher=YouTube}} This would be followed by a 21-year hiatus, until Honda reintroduced the new 3.5-litre RA121E in {{F1|1991}}.{{Cite web|url=https://www.youtube.com/watch?v=Jtm_R87bR7I|title=1991 McLaren MP4/6 F1 Sound - Honda 3.5 V12 Engine Screams at Goodwood|access-date=10 November 2021|publisher=YouTube}} The RA121E would go down as the last V12 engine to win a Formula One World Championship.{{Cite web|url=https://www.ultimatecarpage.com/car/346/McLaren-MP4-6-Honda.html|title=1991 McLaren MP4/6 Honda - Images, Specifications and Information|website=Ultimatecarpage.com|access-date=10 December 2019}} Honda's last-ever V12 engine, the RA122E/B, raced in {{F1|1992}}.{{Cite web|url=https://www.racecar-engineering.com/news/natural-aspirations/|title=Natural Aspirations|first=Racecar|last=Engineering|date=June 25, 2020}}