This International Standard specifies the nominal dimensions and tolerances which affect the interchangeability between clutch housings for spring-loaded clutches and mating parts for reciprocating internal combustion engines. All other dimensions and tolerances are left to the discretion of the component manufacturer. This International Standard applies to reciprocating internal combustion engines, with the exception of engines for aircraft and passenger cars; it may be used for other engine applications where no specific International Standard exists. Clutch housings of size codes 1 to 4 in table 1 are recommended for commercial vehicles and buses.