How high-octane gas burns, the ignition timing issue, and how modern electronically controlled LPG systems affect the engine.
As petrol prices rise, drivers turn to LPG: gas costs roughly half as much with only slightly higher consumption, so conversion pays back quickly. Yet claims that LPG wears out engines are widely debated.
Gas has a much higher octane rating than petrol and burns more slowly, so ignition needs to be advanced compared with petrol. Otherwise, power loss and valve overheating can occur. Older systems relied on a compromise timing between the two fuels, which caused problems.
Newer-generation systems for engines with electronic ignition control select the right timing for each fuel automatically; they cost more but are safer for the engine.