Choked or taper-ground cylinders are used to provide what?

Choked or taper-ground cylinders are used to provide what?

• A. A straight cylinder bore at operating temperatures
• B. Increased wear at cold start
• C. Increased friction
• D. Reduced cylinder bore straightness

Answer: (A)

Choked or taper-ground cylinders are designed to compensate for how parts expand when the engine heats up. As the engine reaches operating temperature, the cylinder bore expands and the surrounding components also change shape. If the bore were machined perfectly straight while cold, this expansion can cause distortion that makes the bore less true or even out of round at temperature. By grinding the bore with a slight taper or choke, the machining anticipates that thermal growth so that, when hot, the bore becomes straight and true. This ensures uniform clearance for the piston rings, better seal, and more consistent wear during normal operation. The other options describe effects that this technique is not intended to produce (increasing wear at cold start, increasing friction, or reducing bore straightness).

Choked or taper-ground cylinders are designed to compensate for how parts expand when the engine heats up. As the engine reaches operating temperature, the cylinder bore expands and the surrounding components also change shape. If the bore were machined perfectly straight while cold, this expansion can cause distortion that makes the bore less true or even out of round at temperature. By grinding the bore with a slight taper or choke, the machining anticipates that thermal growth so that, when hot, the bore becomes straight and true. This ensures uniform clearance for the piston rings, better seal, and more consistent wear during normal operation. The other options describe effects that this technique is not intended to produce (increasing wear at cold start, increasing friction, or reducing bore straightness).