Automotive Engines

1. Automotive Engines Part 6 (Valvetrain)

2. Valvetrain • The collection of parts operate the valves. • The Valvetrain includes the various parts that convert the camshaft's rotary motion into reciprocating motion at the valves, and the valves and their associated parts. • These parts include:

3. 5 Valvetrain 4 6 • Cam • Lobe • Lifter • Push Rod • Rocker Arm • Valve 3 1 2

4. Valvetrain Parts Cont. • Seals, Retainers/Rotators, Keepers • Rocker Arms, Followers, Push Rods • Guides, Seats, etc.

5. Cyl. Head Parts • Guides • Seats • Valves • Springs • Cups (Al. Heads) • Retainers • Seals • Keepers • Rockers

6. Valves • Made of: • Steel • Stainless • Titanium

7. Valve Spring • Generally a coil of wire, that closes the valve after it has been opened by the cam, and prevents the valve from bouncing on its seat.

8. Valve Retainer/Rotator • Retainer • Connects Valve to spring • Rotator • Rotates Exhaust Valves to eliminate hot spots

9. Valve Spring Keepers • Cone shaped wedges hold retainers to valves

10. Rocker Arm • A reciprocating lever, generally used to multiply valve lift

11. Follower (OHC) • Follower: Similar to a Rocker Arm • Lifter • Valve • Lobe 4 2 1 3

12. Shim & Bucket (OHC) • Cam Acts on Valve • Shim is removable • Adjusts lash

13. Pushrods • Transfer lifter motion to rocker arm. • Most are hollow to transfer oil to valves & rockers.

14. Valvetrain – The End