This article compares the IC (Otto) engines, primarily on their power/weight ratio; this being a key issue to assess the usability of an engine for a particular task (ie transport, local power transformation, ...). Primarily the difficulty of repair/convertion and durability is important, since most engines will probably be scavenged and repaired, rather than built. Only 4-stroke engines are mentioned, since 2-stroke engines can't be converted to a emissionless IC-engine. Note that Diesel engines aren't mentioned as they have a very poor power/weight ratio (atleast the durable, low-maintenance engines), although they are generally "considered to be" very fuel-efficient. They can nevertheless be seen used in ships, as in these vehicles weight is less of an issue than in ie road or aerial vehicles.

Type Difficulty of repair Difficulty of convertion to emissionless ICE Power-to-weight Durability Production cost Fabrication requirements Difficulty of production
Engines using liquid matter cooling
ICE straight engine ? ? ? medium ?? ?
ICE V-engine ? ? ? ? ?? ?
ICE W-engine ? ? ? ?? ? ?
Opposed piston engine ? ? ? ?? ? ?
ICE X-engine ? ? ? ?? ? ?
ICE rotary engine (Wankel) ? ? ? ?? ? ?
ICE rotary engine (Quasiturbine) ? ? ? ?? ? ?
Engines using solid matter cooling
ICE straight engine [1] ? ? ? good-medium ? ?
ICE radial engine ? ? better then solid matter cooled ICE straight engine good ? ?
ICE rotary engine (conventional) ? ? better then solid matter cooled ICE straight engine good ? ?

Common sources:

  • lawn mower engine --> ICE straight engine, solid matter cooled. Power rating: around 12 HP. Can appearantly be modified upto 35 HP [2]
  • weed wacker engine --> ?

Note 1: is there a method to calculate power rating from erylind contents x amount of cylinders x fuel burned ? Would be useful if power rating is not mentioned on engine.

Note 2: Not sure whether there is a difference in difficulty of repair between older and newer ICE straight engines; appearantly spark ignition was timed only using the timing belt in the past whereas now, sensors are used;[3] sensor doesn't seem too diffult to make though

Note 3: Finally, not sure whether ICE (straight) engines can have their starter system removed (this normally happens using a starter engine connected to the flywheel). This is quite important as it requires not only the extra starter engine, but also a lead-acid battery for the starting. Both add weight, additional difficulty in repair, and extra requirements (ie lead-acid SLI batteries need to have certain level of starting power, actually require temperature regulation, ...) A hand or leg-based starter system, as seen in the AT e-velomobile would simplify things greatly.

Note 4: Not sure whether lawn mower engines actually have a starter engine, this is probably simply swapped with the starter cord. Also, lawn mower engines do not have a spark ignition system using a battery, rather they use simple magneto's (which is a magnet generating power directly from the rotation of the flywheel


  • lawn mower motor --> use in flexwing microlights, if improved to 35 HP
  • weed wacker --> use on motorised bicycles, light ground vehicles (ie AT e-velomobile) [4]
  • car engine --> 100 HP - 200 HP, use in transport aircraft, if several are used per single aircraft
  • ...

See also[edit | edit source]

External links[edit | edit source]

References[edit | edit source]

  1. Lawn mower engine being solid matter cooled
  2. U.S. Lawn Mower Racing Association (USMLRA); Wreckreation Nation documentary
  3. Zo werkt uw auto by Carel Zaal
  4. Mail George Tetz
Page data
Keywords energy, energy conversion, comparisons, ic motors
SDG Sustainable Development Goals SDG07 Affordable and clean energy
Authors KVDP
Published 2010
License CC-BY-SA-4.0
Impact Number of views to this page and its redirects. Updated once a month. Views by admins and bots are not counted. Multiple views during the same session are counted as one. 521
Issues Automatically detected page issues. Click on them to find out more. They may take some minutes to disappear after you fix them. No main image
Cookies help us deliver our services. By using our services, you agree to our use of cookies.