The Ailsa Craig Engine Company was a manufacturer of marine and specialist, made-to-order engines between 1891 and 1972.
Named after the Scottish island of Ailsa Craig, the company began as a bicycle manufacturer in Glasgow in 1891, moving to Putney (and later Chiswick) in London where they began building motor vehicles.
Ailsa Craig produced the world’s first V12 engine in 1904, worked for the Ministry of Munitions and the Admiralty during the First World War and in 1926 was granted a Royal Appointment.
There was further war commitment in 1939 from an additional factory site in Twickenham until after the war when the factory moved to Ashford where it continued to produce high quality diesel engines until sold to Warsop’s Fram Group in 1964. The company was closed down in 1972.
| Engine | Displacement | Power output | Bore & Stroke | Weight |
| Single-cylinder | ||||
| RF1 | 0.80 l 803 cc |
15 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 310 kg |
| RF1M | 0.80 l 803 cc |
10 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 330 kg |
| RFS1 | 0.80 l 803 cc |
10 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 310 kg |
| Two-cylinders | ||||
| RF2 | 1.6 l 1606 cc |
30 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 410 kg |
| RF2M | 1.6 l 1606 cc |
20 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 430 kg |
| RFS2 | 1.6 l 1606 cc |
20 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 410 kg |
| Straight-3 | ||||
| RAS3 | 2.4 l 2410 cc |
45 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| RF3 | 2.4 l 2410 cc |
45 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 500 kg |
| RF3M | 2.4 l 2410 cc |
30 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 550 kg |
| RFS3 | 2.4 l 2410 cc |
30 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 500 kg |
| RKS3 | 2.4 l 2410 cc |
35 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| Straight-4 | ||||
| RAS4 | 3.2 l 3213 cc |
60 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| RF4 | 3.2 l 3213 cc |
60 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 650 kg |
| RF4M | 3.2 l 3213 cc |
40 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 700 kg |
| RFS4 | 3.2 l 3213 cc |
40 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 650 kg |
| RKS4 | 3.2 l 3213 cc |
46 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| Straight-6 | ||||
| RAS6 | 4.8 l 4818 cc |
90 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| RF6 | 4.8 l 4818 cc |
90 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 780 kg |
| RF6M | 4.8 l 4818 cc |
60 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 950 kg |
| RFS6 | 4.8 l 4818 cc |
60 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 780 kg |
| RKS6 | 4.8 l 4818 cc |
70 HP @ 1500 RPM | 4 1/8 X 5 1/2 | – |
| Straight-8 | ||||
| RF8 | 6.4 l 6424 cc |
120 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 900 kg |
| RF8M | 6.4 l 6424 cc |
80 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 1300 kg |
| RFS8 | 6.4 l 6424 cc |
80 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 900 kg |
| V12 | ||||
| RF12 | 9.6 l 9636 cc |
180 HP @ 1500 RPM | 4 1/8 X 5 1/2 | 980 kg |
| RF12M | 9.6 l 9636 cc |
120 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 1450 kg |
| RFS12 | 9.6 l 9636 cc |
120 HP @ 1200 RPM | 4 1/8 X 5 1/2 | 980 kg |