Abstract: An ignition coil includes a low voltage terminal for connection with a battery and a high voltage terminal for connection with a spark plug. An assembly of windings interconnects the terminals. The ignition coil further includes a case containing the windings and the terminals. The case is configured for use with a cylinder head cover having a cylindrical bore with a key projecting radially inward of the bore. A cylindrical portion of the case has a central axis, a rotational locator surface, and an insertion guide groove configured to receive the key in the bore. A helical section of the groove is configured to receive the key when the case is in a first rotational orientation. The helical section is further configured for the rotational locator surface to move into abutment with the key upon rotation of the case from the first rotational orientation to a second rotational orientation.

Abstract: An ignition coil includes a low voltage terminal for connection with a battery and a high voltage terminal for connection with a spark plug. An assembly of windings interconnects the terminals. The ignition coil further includes a case containing the windings and the terminals. The case is configured for use with a cylinder head cover having a cylindrical bore with a key projecting radially inward of the bore. A cylindrical portion of the case has a central axis, a rotational locator surface, and an insertion guide groove configured to receive the key in the bore. A helical section of the groove is configured to receive the key when the case is in a first rotational orientation. The helical section is further configured for the rotational locator surface to move into abutment with the key upon rotation of the case from the first rotational orientation to a second rotational orientation.