1. Review Exam #3 Engine Components

2. Stroke
The distance swept by a piston as it goes from BDC to TDC or from TDC to BDC.

3. Throw is one half (1/2) the stroke
Stroke vs Throw
Throw is one half (1/2) the stroke

4. Intake Compression Power Exhaust
Four Strokes
Intake Compression Power Exhaust

5. Basic Engine Components
Engine Block
Crankshaft
Pistons
Connecting Rods
Camshaft(s)
Intake and Exhaust Valves

6. Configuration
The design of the engine block which describes how the cylinders are arranged

7. Engine Size / Displacement
The combined swept volume of all of the cylinders
Displacement = x D2 x Stroke x (# of cylinders)
Example:
Bore (D) = 4 in Stroke = 3 in # of cylinders = 8
Displacement = x 42 x 3 x 8 = in3

8. Repair Manual Research / Use
Briggs & Stratton Single Cylinder “L” Head Repair Manual

9. Ignition / Spark Test Set Gap to .030 inches
Ensure spark tester is clipped to a good ground on engine block or cylinder head

10. Compression Test At least three to four pulls of starter cord
Hand tighten into spark plug hole

11. Cylinder Compression Leaks
Four common locations:
Intake Valve
Exhaust Valve
Cylinder Head Gasket
Piston Compression Ring(s)

12. Combustion Byproducts
CH4 + O CO2 + 2H2O + Heat +
+ CO + HC + NOX
= Good
= Not so Good

13. Must go through an Air Filter before entering the intake manifold
Air Intake
Must go through an Air Filter before entering the intake manifold

14. Gaskets
A mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. Gaskets allow "less-than-perfect" mating surfaces on machine parts where they can fill irregularities

15. Flywheel
Stores Energy by using inertia/momentum to offset the three non-power producing strokes of the four stroke engine.
A larger/heavier flywheel takes more energy to get it rotating up to speed, but it will store more energy and allow for a smoother ride than a lighter flywheel.

16. Energy Conversion
The Chemical Energy released from bonds breaking in the gasoline is converted (changed) into mechanical energy of the piston traveling down and thermal energy (heat)
Mechanical Energy = 30%
Thermal Energy = 70% (half of which goes out exhaust pipe and the other half is absorbed by the engine block /cylinder heads / coolant}

17. Diameters
Outside
Inside

18. Vernier Caliper Toggle between inches, fraction of inches, and mm
Zeroize
Depth Measurement

19. Springs
Compression
Tension

20. Crankshaft Types
Cast - pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify.
Forged -  manufacturing process involving the shaping of metal using localized compressive forces
Billet – originates as a cast or forged block that must be fully machined to take on its shape.
Given the same type of steel (e.g. 4340, 1020, etc) forging will be stronger than casting. Billet has the capability of being stronger than a forged crankshaft.

21. Crankshaft Measurements
Connecting Rod Journals are same as Crankpin Journals

22. Driven Gear Teeth / Drive Gear Teeth
Gear Ratios
Driven Gear Teeth / Drive Gear Teeth
Example is 75/25 or 3:1
In a four stroke engine, the cam to crank gear ratio is 2:1

23. Stem Tip Face or Seat Margin
Valves
Stem
Tip
Face or Seat
Margin
Tappet

24. Engine Tools
Spring Compressor
Valve Lap Tool