Fuel pump

A pump for a fuel injection system, the pump comprising:

• a main housing;
• a plunger housing arranged to be coupled to the main housing;
• and
• a gasket for arrangement between respective first and second opposed faces of the main housing and the plunger housing, in assembly, so as to seal a compression chamber defined between the main housing and the plunger housing as the gasket is compressed therebetween under an assembly load,
• wherein the main housing comprises a valve bore extending to the first face of the main housing for supplying fuel to the compression chamber, and the plunger housing comprises a plunger bore extending to the opposing second face of the plunger housing, defining a central axis of the compression chamber, and
• wherein, in assembly, a central axis of the valve bore is radially offset from the central axis of the compression chamber such that a stiffness of the main housing varies circumferentially around the compression chamber to define a region of relatively low stiffness proximal to the valve bore and a region of relatively high stiffness distal from the valve bore;
• and
• wherein the gasket comprises a body having:
• an opening for the compression chamber;
• and
• an uneven sealing surface that extends around the opening with a height, relative to a base plane of the gasket, that varies circumferentially so that, in situ, compression of the sealing surface between the main housing and the plunger housing counteracts the assembly load to reduce the load applied to the low stiffness region of the main housing relative to the load applied to the relatively high stiffness region of the main housing.