Valve lifter anti-rotation device having cantilever bridge

A valve lifter assembly comprising:

• a compound collar for limiting in-service rotation of valve lifters, including a mounting sleeve having a first inner peripheral surface forming a first lifter bore, a guide sleeve having a second inner peripheral surface forming a second lifter bore, a bridge attaching the guide sleeve to the mounting sleeve, and an outer peripheral surface formed in part upon each of the mounting sleeve, the guide sleeve, and the bridge;
• a valve lifter including a first lifter end and a second lifter end, a lifting surface facing a direction of the first lifter end, a cam follower mounted to the second lifter end, and the first lifter end is positionable in either of the first lifter bore or the second lifter bore;
• and
• the second lifter bore is enlarged relative to the first lifter bore and congruent with the first lifter bore, such that the valve lifter has an interference-fit installation configuration with the mounting sleeve and a slip-fit installation configuration with the guide sleeve.

An engine valve actuation system comprising:

• a camshaft including a first cam and a second cam, and rotatable about a cam axis of rotation;
• a compound collar including a mounting sleeve having a first inner peripheral surface forming a first lifter bore, a guide sleeve having a second inner peripheral surface forming a second lifter bore, and a bridge attaching the guide sleeve to the mounting sleeve;
• a first valve lifter interference-fitted within the first lifter bore and including a lifting surface structured to actuate a first valve in an engine, and a cam follower in contact with the first cam to reciprocate the first valve lifter in response to rotation of the first cam;
• a second valve lifter slip-fitted within the second lifter bore and including a lifting surface structured to actuate a second valve in the engine, and a cam follower in contact with the second cam to reciprocate the second valve lifter in response to rotation of the second cam;
• the first lifter bore and the second lifter bore are congruent;
• and
• the first valve lifter and the second valve lifter are substantially identical;
• and
• wherein
• the first lifter bore defines a first collar axis, a first major diameter, and a first minor diameter;
• the second lifter bore defines a second collar axis, a second major diameter, and a second minor diameter;
• and
• the second lifter bore is enlarged, relative to the first lifter bore, based on a size of at least one of the second major diameter or the second minor diameter compared to sizes of the first major diameter and the first minor diameter.