Comparison of IC motors
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||?||?||?||? ??||?|
|Opposed piston engine||?||?||?||??||?||?|
|ICE rotary engine (Wankel)||?||?||?||??||?||?|
|ICE rotary engine (Quasiturbine)||?||?||?||??||?||?|
|Engines using solid matter cooling|
|ICE straight engine ||?||?||?||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||?||?|
- lawn mower engine --> ICE straight engine, solid matter cooled. Power rating: around 12 HP. Can appearantly be modified upto 35 HP 
- 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 ; 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) 
- car engine --> 100 HP - 200 HP, use in transport aircraft, if several are used per single aircraft
- Improving system efficiency by combining engines
- Comparison of non-IC thermal motors
- http://en.wikipedia.org/wiki/Tata_Nano: Tata nano engine: a cheap L2-engine with 2 counter-rotating shafts to eliminate vibrations.
- Lawn mower engine being solid matter cooled
- U.S. Lawn Mower Racing Association (USMLRA); Wreckreation Nation documentary
- Zo werkt uw auto by Carel Zaal
- Mail George Tetz