Hydrolock has a number of causes, but no solutions, until now. Serious off-road vehicles have sealed air boxes with snorkels to roof-top height. Some street cars have water traps to help keep water out of the engine. These solutions are always ineffective in deep enough water.

PREP (Pressure Relief / Engine Protection) Spark Plugs offers a revolutionary, patented technology to prevent engine damage from hydrolock. The spark plug is structurally weakened such that the excessive cylinder pressure which develops under hydrolock will permanently deform the spark plug, generating a vent port. Gasses and liquids are permitted to escape the cylinder under hydrolock conditions.

We, at TFI, have pondered the question: "how can a cylinder full of water be pumped out the through spark plug at running speed?" Analysis and experimentation have led to another question: "how much water is in the cylinder?" Water is drawn into the cylinder by the vacuum of the intake stroke. Vacuum accelerates water upward from the ground and into the induction system; but water is far denser and more viscous than the air that ordinarily follows this path. Cavitation, vaporization of liquid water by low pressure, has been shown to occur. Only a small amount of water can cause, and only a small amount of water is usually present in, a hydrolocked engine. A small amount of water with a large amount of air drastically increases the "effective" compression ratio of the cylinder. In many cases of hydrolock, simply venting the air out of the cylinder is sufficient to prevent hydrolock. Provided that the volume of liquid water does not exceed the combustion chamber volume, venting only air from the cylinder will prevent hydrolock. If the volume of water in the cylinder exceeds the combustion chamber volume, by say, 10%, only the extra 10% of the water must be vented, along with all of the air. PREP Spark Plugs are with designed to provide a maximum vent area for expulsion of gasses and small amounts of liquids during hydrolock. Laboratory and field tests show that PREP Spark Plugs can prevent engine damage in all but the most extreme hydrolock conditions.

After PREP Spark Plugs have vented from hydrolock, the plug may or may not still be functional, this depends on the design of the "parent" spark plug from which the pressure relieving spark plug was made. Replacement of the vented spark plug is recommended as soon as it is convenient. No special tools are required for the removal and installation of PREP Spark Plugs; your spark plug wrench is all that is required. On the trail, street or track an engine running PREP Spark Plugs, some of which have vented, will continue to run and be operational until spark plug replacement is convenient. Running the engine for a short time after venting of PREP Spark Plugs is recommended for two reasons: (1) the cycling engine will pump the remaining water out of the cylinder, a little each cycle, and (2) the heat generated by the running engine will evaporate water from within the cylinders, electrical system and in the oil, if present.

Until now, every attempt to prevent the occurrence of hydrolock has been elaborate: snorkels, ducting, water traps, air intake placement; all of these solutions require engineering, fabrication and installation. Sometimes the original vehicle design just does not lend itself to easy hydrolock prevention. Now there is a new, easy to install, technology to prevent hydrolock: merely remove your existing spark plugs and replace them with PREP Spark Plugs. No simpler solution exists, and the payback on your investment can be thousand-fold.