• [+] Engines by cylinder number‎ (9 C)

E

• [+] Engines by cylinder layout‎ (6 C)
• [+] Exhaust systems‎ (2 C, 1 P)

F

• [+] Four-stroke engines‎ (1 C)

I

• [+] Internal combustion engine parts‎ (5 C)
• [+] Internal combustion engines with unusual valvegear‎ (1 C)

O

• [×] Oil engines‎ (2 P, 1 F)

R

• [+] Racing engines‎ (2 C)