Engine pre-heating is nothing new, it's benefits are well documented
in motor sport and aviation but why should you pre-heat RC engines?
RC nitro engines are designed to have a degree of mechanical pinch at TDC which helps maintain a smooth consistent idle. This pinch will naturally diminish throughout an engines lifespan due to the friction of the piston and liner wearing against each other. This wear cannot be stopped, however by pre-heating an engine before starting, the metal components expand and loosens the tight pinch area at TDC causing less metal to metal contact and therefore less engine wear.
The pinch effect is even more apparent when an engine is new and the piston & liner are a very tight fit - pre-heating reduces this tightness making break-in much easier on the other engine components (the conrod for example) which is under great stress during break-in. Other key benefits to pre-heating are:
Less time warming your engine before use which saves a considerable amount of fuel over a period of time.
Sometimes it's very hard to get an engine up to temp. Many
people don't leave their engines long enough before use especially in
cold weather, this will considerably reduce its life span.
Once an engine is pre-heated it can be tuned almost immediately,
reducing the need to adjust it's tune when in use - this helps if you
compete as it prevents the engine running lean during the A main.
RC nitro engines are not cheap and pre-heating will ensure the engine will perform at it's best throughout its life - saving you time and money in the process.