aircooled engine technology - grafton school · pdf filetest #2 format ≈ 90...
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AirCooled Engine Technology
AirCooled Engine Technology
Test #2 Review
Covers Chapters 2, 3, 15, 16, 17 OEM Internal Parts Worksheets
Specialty Tools & Safety Precision Measuring
Test #2 Format ≈ 90 Questions True & False
Matching Definitions Short Answer
Internal Part Identification Service Procedures
Questions About Lab Work
AirCooled Engine Technology
Best Way To Study Use Chapters 2, 3, 15, 16, & 17 Multimedia!!
Take Notes from Study Guides & Textbook!
Tools to Identify & Know Why
Spark Tester
Fire Triangle
Need about 9 to 12 kVolts To Lightup the A/F Mix
Cylinder Leakage Tester
Tools to Identify & Know Why
Fire Triangle
Pinpoints the Source of Leakage or
of Low Compression
Compression Testers
Tools to Identify & Know Why
Fire Triangle
Need about 40 or more Psi To Warmup the A/F Mix
Torque Wrenches
Tools to Identify & Know Why Proper Torque & Sequence/Pattern Prevents Over & Under Tightening
Telescoping Gauge
Small Hole Gauges
Tools to Identify & Know Why
Check Inside Diameters
Flat Feeler Gauges
Thread Pitch Gauges
Tools to Identify & Know Why Clearance Checks Between Parts
Identifies Coarseness
Dial Caliper
Micrometer
Tools to Identify & Know Why Precision Measuring
Flywheel Strap Wrench
Tools to Identify & Know Why
Holds Flywheel when tightening or loosening
Piston Ring Compressors
Tools to Identify & Know Why
Piston Installation into Cylinder
Piston Ring Expanders
Tools to Identify & Know Why
Ring Removal from Piston Ring Installation on to Piston
Valve Lapping Stick
Tools to Identify & Know Why
“Lapsin” the Final FacetoSeat Fit
Done After Face & Seat Cutting to 1º Interference Angle
Piston Ring Groove Cleaners
Tools to Identify & Know Why
Do what they say they will!
Cylinder Deglazing or Honing Tools
Tools to Identify & Know Why
Recondition Cylinder Wall Crosshatch to hold oil for Lube & Sealing
Valve Seat Cutter Kit
Tools to Identify & Know Why
Accurately aligns in guide & cuts seats concentrically to nearest 1º
Valve Face Cutter Kit
Tools to Identify & Know Why
Accurately aligns on valve stem & cuts valve faces concentrically to nearest 1º
From Chapter 15 Worksheet
4. Marking parts during disassembly 5. Organizing your repair job is smart 6. Integral Cylinders & Heads & Crankcase
From Chapter 15 Worksheet
7. Remove pistons through the top 8. Remove the carbon ring ridge 1 st
From Chapter 15 Worksheet
10. Cylinder wear 90º to crankshaft centerline 11. Cylinder taper – larger at the top 12. Deglazing restores crosshatch
From Chapter 15 Worksheet
15. Cylinders are oversized in steps of .010” 16. Honing is an abrasive finishing process 17. Rigid honing repairs taper & outofround
From Chapter 15 Worksheet
18. Crosshatch holds oil to help seal the rings 19. Oil cleans, cools, lubricates & seals
From Chapter 16 Worksheet
2. Low compression may mean bad rings
From Chapter 16 Worksheet 4. Ring lands are the spaces between grooves 5. Piston skirt is the side of the piston 6. 2 cycle pistons can open & close ports
From Chapter 16 Worksheet 8. CamGround piston is oval when cold 9. CamGround piston is round when hot 11. Piston head runs hotter than the piston skirt
From Chapter 16 Worksheet 12. Scavenging is accomplished by the
shape of the piston head or crown: Dome = Loop Scavenging Contour = Cross Scavenging
From Chapter 16 Worksheet 13. Piston rings seal compression pressure
From Chapter 16 Worksheet 16. Floating rings (4 cycle) move in grooves 17. Pinned rings (2 cycle) don’t float 18. Ring Groove Side Clearance ≈ .002”
From Chapter 16 Worksheet 19. Compression Rings = Top rings 20. Oil Control Ring = Bottom ring
From Chapter 16 Worksheet 22. Too much end gap = problems (leakage) 23. Too little end gap = problems (too tight) 24. Measure ring end gap with flat feeler gauge 30. Pistons with offset writ pins reduce slap 30. Pistons with offset wrist pins have a mark
From Chapter 17 Worksheet 2. Purpose of the connecting rod 3. Friction bearings (precision inserts & bushings) 4. Antifriction bearings (needles, ball, roller) 5. Precision insert bearings
From Chapter 17 Worksheet 9. Connecting rods & caps are matched sets 12. Always torque connecting rods! 13. Purpose of the crankshaft
From Chapter 17 Worksheet 14. 2 x throw = stroke of the engine 15. Counterweights balance out vibration 17. Some crankshaft end play is necessary
From Chapter 17 Worksheet
From Chapter 17 Worksheet
19. Bearing oil clearance is necessary 20. Plastigage® used to check bearing clearance 21. Journals wear undersize! 21. Bores wear oversize!
From Chapter 17 Worksheet
22. Oil seals prevent leakage around shafts 23. Oil seal knife edge faces the fluid sealed
From Chapter 17 Worksheet 24. Know the parts of poppet valves 25. “Keepers” can be pins, collars, or retainers 29. Lack of spring tension causes valve flutter 29. Define valve flutter: bounce as it closes! 30. Valve guides are repaired before valve seats
From Chapter 17 Worksheet
From Chapter 17 Worksheet 33. 3angle valve jobs are best (60° 30° 46°) 33. Interference fit is 1º difference seattoface
46º
45º
60º
31º
46º
Throat
Top
Seat
From Chapter 17 Worksheet 36. Repair the guides first, then service the seats 37. Measure valve clearance cold (expansion)
From Chapter 17 Worksheet 38. Too little valve clearance is a problem 39. Too much valve clearance is a problem 40. Stems are ground to adjust Lhead clearance
From Chapter 17 Worksheet
43. Dampening coils prevent valve flutter 45. Torque sequences are important
From Chapter 17 Worksheet 48. Reed valve stops prevent “overopening”
From Chapter 17 Worksheet 49. Crank & Cam gears must be timed! 49. Crank always goes 2x speed of cam
Cam always goes ½ the crank RPM
From Chapter 17 Worksheet 50. Automatic compression release makes
cranking easier!! (on manual & electric start)
From Chapter 3 Worksheet ___ 1. Measurement ___ 3. Dimension ___ 5. Clearance ___ 2. Specification ___ 4. Tolerance ___ 6. Increment
A. A space between 2 moving machine parts left to prevent clashing or to permit relatively free motion.
B. A measurement of length, width, or thickness in a particular direction or across a diameter.
C. The permissible range of variation in a dimension or characteristic of an object.
D. The act of determining the dimension or quantity of something, especially by comparison to a standard.
E. A detailed description of requirements, dimensions, or materials.
F. The difference between two measurement units or values.
From Chapter 3 Worksheet Know how to “use” & express decimals .001” increments .002” is about a human hair diameter Measure with a Dial Caliper Measure with a Digital Caliper Change inch pounds into foot pounds Change foot pounds into inch pounds
From Briggs & Stratton Worksheet
Know Questions: 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 15, 16, 17, 18, 19
and the photos that accompany them!
Know the Tools – Names & Uses
From Tecumseh Worksheet Know Questions: 1, 4, 8, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 31, 33, 34 and the photos that accompany them!
Fire Triangle
Air
Fuel Heat of 1) Compression 2) Spark
Be Able to Explain This Concept…
…from how an engine runs good to how it might run poorly
Fire Triangle
Air
Fuel Heat of 1) Compression 2) Spark
Know how to diagnose with the
• Bore: Cylinder Diameter
• Stroke: Length of Piston Travel Distance from TDC to BDC One Piston Movement Up or Down
• Displacement: Total Cylinder Volume
Poppet Valve Parts
OHV Valve Train Parts
Quiz Yourself
[ ] Cross Scavenging (contoured piston)
[ ] Loop Scavenging (domed piston)
[ ] Cross Scavenging (contoured piston)
[ ] Loop Scavenging (domed piston)
Quiz Yourself
[ ] Holds oil for Lubrication
[ ] Holds oil for Sealing of Rings
[ ] Holds oil for Cooling
[ ] Holds oil for Cleaning
Name of the Pattern?
How is it installed?
Quiz Yourself
[ ] Rotates Exhaust Valve to wipe the face & seat clean & seal better
[ ] Rotates Exhaust Valve to cool it
[ ] Rotates Exhaust Valve to prevent flutter/bounce (incomplete closing)
What is it?
Purpose?
Quiz Yourself
[ ] Rotates Exhaust Valve to wipe the face & seat clean & seal better
[ ] Rotates Exhaust Valve to cool it
[ ] Variable Rate Spring prevents flutter/bounce (incomplete closing)
What is it?
Purpose?
Quiz Yourself
[ ] Seals valve stemtoguide fit to prevent oil burning & A/F mixture dilution
[ ] Seals valve stemtoguide fit to prevent compression loss
[ ] Seals valve stemtoguide fit to prevent flutter/bounce (incomplete closing)
What is it?
Purpose?
Quiz Yourself
[ ] Measuring Piston Ring End Gap
[ ] Measuring Ring Groove Side Clearance
[ ] Measuring Piston Ring End Gap
[ ] Measuring Ring Groove Side Clearance
Quiz Yourself
Lhead valve arrangement Ihead valve arrangement
Valve StemtoTappet Clearance!!
Grind the Stem to Adjust!
Integral Block & Cylinder
Sump Covers
Right Angle Auxiliary Drive Mechanical Governor
2 stroke cycle multi piece crankcase & removable cylinder
Cylinder Heads
Combustion chambers inside the cylinder head
Overhead valve cylinder heads
2 stroke cycle removable cylinders…3 rd port valving
2 stroke cycle integral crankcase & cylinder
Cylinder Sleeves
4 cycle 2 cycle
Cast in place Flanged…replaceable
Crankshafts
PTO Journal Magneto Journal
Crankpin Journal
Valve Timing Gear
2 stroke cycle, 2 cylinder crankshaft
TC200 crankshaft
Counter balance systems used to reduce vibration
4 stroke cycle engine pistons
Notch towards flywheel or arrow towards front of engine Indicates offset wrist pin used to reduce piston slap
OHV valve reliefs
2 stroke cycle pistons
3 rd port or piston port valving…no reed valve required
Note: pinned piston ring
4 stroke cycle pistons…3 rd ring groove for oil control ring
Teflon coated skirt for heat resistance & reduced friction
Slipper skirts allow piston to get closer to crankshaft counter weights
Contoured piston head for cross scavenging
Domed piston head for loop scavenging
Damage from lack of lubrication
Damage from preignition
Pistons & their Wrist Pins
A variety of connecting rods
Connecting rod bolt locking devices
HarleyDavidson onepiece rods…need a 2piece crankshaft
2 cycle piston & 2 rings
4 cycle piston & 3 rings
Top ring = compression Middle ring = compression & scraper Bottom ring = oil control
Piston ring set with a 3piece oil control ring
2 cycle crankshafts with 1piece rods
Centrifugal clutch for chainsaw operation
Camshafts
Bump Compression Release
Mechanical Compression Release
Auxiliary Drive & Oil Slinger
HD Camshaft
Nylon Gear & Lobes
Mechanical Compression Release for easier cranking
Exhaust Lobe
MCR Starting Position Holds Exhaust Valve Open
MCR Running Position Allows Full Compression
A variety of poppet valves
Push Rods from OHV engines
Valve Lifters
Valve Tappets
Cam Followers
Hydraulic Roller Lifter
Rocker Arms
Push Rod Guide Plate
Valve Stem Seals used to prevent lean A/F mixtures
Burned Valve Face
Valve Stem Seals used to prevent oil being drawn through valve guides & burning in the combustion chamber
Replaceable Valve Guides
Valve Rotators Valve Keepers or
Retainer Washers
Valve Collars
Increase Seat & Face Life
Valve Guides & Rotators
Valve Springs
None here have dampening coils to prevent flutter
…coils wound closer together at one end
…closer coils go toward the head of the valve
Cylinder Head Gaskets
Thrust Washers to reduce crankshaft end play
Sump Cover Gaskets can adjust crankshaft end play too
Gasket Sets
Sump Cover Gaskets are also used to adjust crankshaft end play