We have received several telephone calls and e-mails concerning clarification of the allowable thicknesses of head gaskets in the Stock Classes. Because of this, we feel it is important to clarify this rule to avoid problems at the APBA Watercross Nationals, IJSBA World Finals, and all other IJSBA Sanctioned Races.
Under Section 6.3.11 on page 18 of the 2006 IJSBA Rulebook section 1 reads:
- Replacement gaskets may be used but must be of the same type (e.g. sheet, o-ring, etc.) as their OEM counterpart. Base gasket cannot be thicker than 0.8mm (0.032 in).
Here is the plain word interpretation of the rule. This is exactly how this rule has been enforced since the inception of the stock classes:
The Head Gasket must be the same thickness as the OEM gasket. If the OEM gasket is an O-Ring type gasket then the replacement gasket must be an O-Ring gasket. If it is a sheet type gasket (e.g. metal, copper, fiber) then the replacement must one of the different types of the sheet gaskets. The Base Gasket can be any thickness but not more than 0.8 mm (0.032 inch).
Bottom line: If you have a thinner than stock head gasket on your Stock class boat get it fixed or face disqualification. It is YOUR responsibility to ensure that your PWC complies with all IJSBA rules.