I feel that everyone should practice true engine out manuevers. Learning to fly without the engine is vital as we spend alot of time in the air. It is only a matter of time before one will experience an engine failure of some sort. In approximately 20 years, I have had numerous failures with various causes. The failures were in different types and brands of aircraft. On a Phantom ultralight, I had a foam oil impregnated air filter split apart because of age and high speed flight pulled back on the filter until it ripped open and this changed the mixture so radically that the engine lost power, causing an emergency landing on a country road. The quick fix was to reach in my pocket and pull out a dime to use as a screw driver. I loosened the clamp and rotated the filter 180 degrees to have the remaining good side facing into the wind and prop. The air pressure from the tractor prop held the filter tight enough to close the gap in the torn side which allowed me to fly the short distance back to my own field and make the proper repair. I have seen head gaskets blow, spark plugs foul, lead fouling, bad fuel from contaminated fuel tanks at FBO's (verified), drive belt failures and fuel pressure issues. I have seen the old ADS electric starters seize up and steal the engines power. All of the items mentioned resulted in emergency landings either on or off field.