1. ENGINES AUTO 1-2
Pasco High Auto Shop

2. 1. Engine Block

3. 1. Engine Block Metal foundation
Supports crankshaft and usually camshaft made of cast iron or aluminum, aluminum parts that wear will have metal inserts that are pressed or cast into the block.
Cylinder - round hole formed in block bored and honed to a fine finish, acts as a guide for piston and a container for the fuel charge

4. 2. Cylinder Sleeves
Round pipe like liners

5. 2. Cylinder Sleeves
Removable type or cast into block, wet and dry sleeves,
DRY pressed in block supported and surrounded, its full length - most common gas engine.
WET pressed in block supported only at top and bottom - cooling water comes in direct contact - heavier construction has sealing rings

6. Securing sleeves
When cast into block they usually have grooves in the outside of sleeves to secure it when pressed in it can have flange on top or will be held in only by friction of a pressed fit - head will keep it from coming up.

7. 3. Piston
Sliding plunger in cylinder creates vacuum on intake stroke, compresses mixture on compression stroke transmits and contains the pressure of the firing stroke, cleans the cylinder of burned gases on the exhaust stroke.

8. Piston materials aluminum - cast - most common,
forged- found in hi-performance engines

9. Expansion of Piston
If the piston is to loose it can cause piston slap, piston too loose in cylinder tips from side to side

10. Old styles of Piston split skirt, skirt closes as piston warms up.
T slot, same as split skirt but has a T top to prevent heat of piston head transferring to skirt
steel strut, steel cast into aluminum piston steel expands less then aluminum and helps reduce expansion

11. New style cam ground, minimum clearance on thrust sides egg shaped
thrust surface, side of piston that is at right angles to crank shaft and piston pin surface side that prevents tipping and supports the piston.

12. skirts full skirt skirt goes all the way around piston not cut away.
slipper skirt, piston skirt cut away below piston pin for counter weights piston lighter reduces inertia load on bearings makes engine more responsive

13. piston temperature
head of piston up to and above 600' F bottom of skirt about 300'F, head of piston is .030 to .040 in smaller then skirt to allow for expansion top can be of different shapes

14. Piston Shapes
flat, dome, wedge, irregular - to help in exhausting burned gases
Piston pin boss, section of piston that supports piston pin inboard pin boss - most engines, out board pin boss - performance and competition
valve reliefs- small indentations machined into the top of the piston.

15. 4. Piston rings
3 piece Oil ring

16. 4. Piston rings ride in grooves in piston head to seal the cylinder
types of rings, compression - prevent pressure leakage into the crankcase
different grooves, bevels, and chamfers causes internal stress causing scraper action on downward stroke taking any oil down that was missed by the oil ring

17. Piston rings
firing pressure forces top ring down for full face contact
inner groove usually goes up
outer groove usually goes down
material, rings made of cast iron, some are chrome plated, some are molybdenum coated or a grooved filled with moly, some rings are stainless steel

18. Oil control rings -
scrape oil off cylinder wall and send pack to crank case all new sets are three piece expander and two steel rings some old oil rings are just one ring break easy.
compression and oil control rings can have an expander ring to help force out the ring

19. Piston ring gap joints, most common - butt
lap and bevel have been used
some engines have a pin in piston ring groove to prevent ring from moving
piston ring gap usually for each inch of cylinder diameter

20. Ring Width
Distance from the top to the bottom of the ring

21. heat dam
groove in head of piston that prevents or lowers the amount of heat transferred to the top ring
top ring groove insert, metal insert cast into aluminum piston with piston groove cut out of insert to help prolong the life of the piston

22. 5. Piston Pins steel pin used to connect piston to connecting rod
case hardened, soft center .004 outside hardened highly polished

23. securing piston pins
1. full floating pin, snap ring each end pin can turn in piston bosses and connecting rod may have bronze bushing

24. securing piston pins
2. press fit (rod pressed into the connecting rod) pin turns in aluminum piston boss.

25. securing piston pins
3. pin locked to rod by bolt not very common.

26. 6. Connecting Rods
connect piston to the crankshaft upper end oscillates lower or large end rotates lower end must be split for installation of bearing and installation on crankshaft journal. before removing number rod and rod cap on same side with a number.

27. 6. Connecting Rods
Steel Rod Aluminum Rod

28. 7. Insert Bearings
removable bearing split in two pieces for easy installation and removal

29. 7. Insert Bearings
steel back with soft lining, coating can be of babbitt, copper-lead-tin or aluminum coating
locating tabs help keeps insert bearing from turning

30. Insert Bearings
crush height the .001 to .002 protruding above rod cap and rod that when bolted together forms the tight fit that prevents the bearing from turning.
An undersize bearing is used on a crankshaft that has been machined to a smaller size.

31. BEARING PERFORMANCE
load strength- must withstand pounding from compression and firing stroke
anti scuffing - if oil pressure is lost lining must be soft enough to prevent crankshaft journal from being scratched or scuffed
corrosion - must resist corrosion from vapors and acids in crankcase
conformation - must conform to shape of crankshaft journal

32. BEARING PERFORMANCE
embedability - must allow small particles to embed itself into bearing material so journal won't be scratched
temperature - must work equally well both hot and cold must transfer heat well
oil hole or groove for lubrication

33. BEARINGS rod bearings, bearings in the connecting rod
main bearings, bearings that go where the main bearing cap hold the crankshaft in place.

34. THRUST BEARINGS
thrust bearing, has sides on to help prevent end play of crankshaft, sometimes use a separate piece for the side.

35. 8. Crankshaft Crankshaft, change reciprocating motion to rotary motion
made of Forged steel (should ring when you hit it with a hammer) or cast iron
counter balances, forged in crank to offset weight of crankshaft throw

36. Crankshaft
crankshaft throw, the part of crankshaft that the connecting rod fastens to also refer to as rod journal
crank main journal, by use of main bearing caps crankshaft is bolted to block
crankshaft is drilled so oil can be fed to main bearings and rod bearings, crankshafts are ground and highly polished

37. 9. Harmonic Balancer or Vibration Damper
Helps absorb torsional vibration of crankshaft and smooth out firing pressure of each cylinder, 2 pieces with rubber plug or lining

38. 10. Flywheel 1. smooth out engine speed 2. mounting surface for clutch
3. starter motor engage ring gear to start engine
4. carry engine through power strokes

39. 11. Camshaft
opens the valves in engine cam lobes open the valves one per valve shape of lobe determines how long valve stays open and how far it opens also gear to drive the distributor and oil pump an eccentric may be ground or bolted onto cam to drive the fuel pump

40. 12. Timing chain, belt and gears
drive chain or belt that connects the crankshaft gear(driving force) to the cam shaft gear (the driven force) camshaft turns at 1/2 crank shaft speed.
light duty chain, heavy duty - double roller, driven by all gears, crank gear - steel, cam gear - steel, aluminum, pressed fiber, plastic, must be aligned

41. tensioner for belt or chain
Off of a 96 Olds
chain drive
Off a 75 Toyota 2TC
chain drive

42. 12. Timing chain

43. 12. Timing gears

44. 13. Valves
device used to open and close the valve port, engines have 2 3 or 4 valves per cylinder
some valves have a special hard facing on the face stellite faced valves

45. Valves
valve faces are ground at different angles and most common. interface angle valve face 44 seat 45, exhaust valve may climb out of seat
cooling, heat dissipates through valve seat and valve guide some valves (heavy duty truck) are sodium filled to help transfer heat.

46. CAUTION:
SODIUM, IF DROPPED INTO WATER WILL BURST INTO FLAMES WILL CAUSE SERIOUS BURNS IF IT GETS ON TO YOUR SKIN.

47. 14. Valve seat
Part of head or block that valve face comes in contact with to seal cylinder. Can be part of head or an insert that is pressed in. most now are hardened seats valve seat angle 30 and 45

48. 15. Valve springs
closes valve when lifter comes off cam lobes some valves use 2 springs per valve, Must measure valve spring installed height, coil bind - spring can only go together so far.

49. 16. Valve spring retainer
holds spring in place with a valve lock or keeper

50. Valve keepers
holds valve in place maybe called a stem lock

51. Valve Stem seals
Valve seals prevent oil from being drawn into the engine. Deflector seals usually called Umbrella seals and a Positive seal are the most common types. GM uses a O-ring on there engines.

52. 17. Valve guide
hole through which valve passes to keep it in proper alignment can be cast into head or pressed in must have clearance

53. 18. Valve lifter mechanical - solid
lifters are solid or hollow made of cast iron bottom that contacts camshafts is hardened adjustment is taken care of in rocker arms on most engines some lifters are adjustable.

54. Hydraulic Valve lifter
Hydraulic, self adjusting has zero valve lash clearance(No space between parts), use engine oil under pressure to operate are quieter then solid lifters operation, may use flat check valve or ball.

55. Hydraulic Valve lifter
Roller Lifter - has a small roller that rolls on the camshaft.

56. 19. Lifter guide
bore in block that contain lifter has oil passage in it to supply oil to lifter

57. 20. Rocker Arm
Transmit cam lobe action to the valve stem, two type adjustable and non adjustable can be mounted on shaft or a individual stud, overhead cam-rocker arm operates on camshaft (eliminates the middle man), roller rockers

58. 20. Rocker Arm

59. 20. Roller Rocker Arm

60. 21. Push rod
Transmits valve train motion from valve lifter to rocker arm

61. 22. valve port
passages which allow the air fuel mixture in and the burned fuel out

62. 23. Crank case or oil pan
reservoir for oil usually made of stamped steel attached to the bottom of block the oil pump is usually with in this reservoir

63. The
End
Scott
Salisbury