The use of push rods becomes necessary in a...

🔍 Key Concepts

• Valve train components in a diesel engine: camshaft, lifters/tappets, push rods, rocker arms, valves • How distance and alignment between camshaft and valve gear affect the need for intermediate parts • The basic function of a push rod in transmitting motion in an overhead valve (OHV) system

💭 Think About

• Ask yourself: in which choice is there a clear need to carry motion from one place to another in the engine, rather than just change direction or timing? • Which option describes a situation where the camshaft cannot act directly on the rocker arm or valve because of its physical location? • Consider which items listed (rocker arm pivot point, multiple valves, hydraulic lash adjusters) can be handled without needing a long mechanical link like a push rod.

✅ Before You Answer

• Identify which option explicitly involves separation in space between the camshaft and the valve gear • Confirm the primary purpose of a push rod: does it mainly solve a distance problem, a timing problem, or a clearance (lash) problem? • Eliminate any choices that describe features that can exist with or without push rods, rather than situations that actually make push rods necessary.

The use of push rods becomes necessary in a diesel engine when __________.

the camshaft is located some distance below the valve gear

the rocker arms are pivoted near their centers

two or more valves must be opened and closed at the same time

hydraulic valve lash adjusters are used

🔍 Key Concepts

💭 Think About

✅ Before You Answer