1. Engine: Top End Construction

2. Valve Covers - contains oil being splashed around valve galley - allows easy access for inspection and top end adjustment or repair - usually holds positive crankcase ventilation valve (PCV valve) - cap for adding engine oil is usually found on this part

3. Valves - allows air fuel mixture or exhaust gases to enter and leave the engine - intake valves are always bigger in diameter - are restrained in size so multiple valves are used in a single cylinder - exhaust valves are sodium filled to absorb more heat

4. Valve 101 - Margin is the useable amount left to re grind if needed - The seat seals against the face of the valve - The valve guide keeps the stem of the valve centered

5. Valve Issues - valves need to make a good seal in order to contain high pressures - loss of pressure is due to burnt valve, carbon deposit build up, bent valve, or loose valves (worn valve guides)

6. Valve Performance - stock sealing surface is 3 angles to allow for better air flow/sealing - performance valve grinds will do 5 angles which include back cutting valve for even more Cubic Feet Per Minute

7. Valve Performance - stock valve is in the center -Vortec valve is on the left and incorporates a 30 degree back cut -Manley stainless valve is on the right and uses a thinned valve stem for improved air flow and lightening

8. Valve Contact - Prussian Blue (engineer’s blue) is a dark dye mixed with oil - The prussian blue is applied to valve only and valve is rotated against seat to see where the valve is contacting

9. Valve Contact... - lapping compound is oil mixed with extremely fine grinding grit -Lapping sticks are used to suction to the face of the valve -Valves are rotated with lapping compound to match contact areas - once completed, Prussian blue is used to recheck the lap

10. Valve Keepers - valve keepers prevent the spring from releasing when installed - Keepers also allow the valve train to be disassembled -- need to have valve spring compressed to remove/install keepers

11. Valve Keepers... -

12. Valve Springs - the spring allows the cam lobe to open the valve (compressing the spring) - valve springs’ job is to return the valve face against the seat and ensure a good seal as fast as possible

13. Valve Train Operation at 14,000 RPM

14. Valve Springs Float

15. Valve Spring Compressors

16. Valve Seals (umbrella seals) - valve seals allow a small amount of oil to lubricate the valve stem without excessive amount passing into combustion area (blue smoke only at start up)

17. Rocker Arms -rocker arms redirect forces from pushrods to the valve -Each valve will have one rocker arm to allow for independent adjustment -most common type is a solid rocker arm

18. Rocker Arms… -Rocker arms use set screws and lock nuts to allow for valve lash adjustments (play in between rocker arm/valve) -Feeler gauges are used to check the play and are accurate to.001” -Some valve lash is needed to allow for expansion/low friction/ensure that valve is not held down even a little

19. Rocker Arms… -Roller rocker arms are used in diesel and performance engines to reduce friction and wear -roller rocker arms still need valve lash to be adjusted

20. Pushrods -Pushrods are light rigid tubes that transmit force from the lifters to the rocker arm -They are hollow to allow for oil to lubricate contact points

21. Lifters -lifters transmit force from camshaft lobe to pushrods -One end slides up and over the lobe shape (high friction)

22. Hydraulic Lifters -roller lifters have reduced friction and wear -Hydraulic lifters use oil pressure to remove any play or looseness in the valve train

24. Camshaft -Camshafts control the timing of the intake/exhaust valves opening and closing -They also control how much the valves open (lift) and the length of time they are open (duration)

25. Camshaft… -Camshaft specifications are design to meet certain driving conditions: fuel economy, more torque, more horsepower, low emissions -Camshafts are heat treated to resist wear and are ground to extremely tight tolerances based off the engine requirements

26. Valve Overlap -Valve over lap allows the fresh air fuel mixture to push out all of the exhaust gases -back pressure also helps to pressurize the combustion area

27. Variable Valve Timing

28. Camshaft… -Camshafts can be single over head cams (SOHC) or dual (DOHC) -They are attached to a sprocket that is driven from the crankshaft by means of chain/belt/gear

29. Performance Camshafts -In order for camshafts to be light and spin faster, manufacturers produce hollow camshafts and hydroformed camshafts

30. Cylinder Head -Cylinder heads hold the position of the valve train and house the combustion chamber -they are made of aluminum or cast iron and contain passages for oil and coolant to flow through and cool/lubricate parts -They also have passages (ports) to allow the air/fuel mixture and exhaust gases to pass to and from the combustion chamber

31. Volumetric Efficiency -Volumetric efficiency is the amount of air brought through the engine compared to the theoretical maximum -The more air the engine can “breathe” the more power -This is the key to increasing power in an engine

32. Cylinder Head Porting & Polishing -Stock cylinder heads are often sand cast and the ports that move air have a rough texture and are poorly sized

33. Cylinder Head Gaskets -Cylinder head gaskets must hold in high compression pressures and allow oil and coolant to pass without having leaks -When changing head gaskets, ALL old material must be removed before a new is installed

34. Cylinder Head Sludge -Oil needs to be free to flow up to oil the top end components -It also must be able to drain back through the tiny oil returns

35. Cylinder Head Gaskets... -High compression engines require copper gaskets -Copper gaskets can be reused if annealed (25% elasticity)

36. Exhaust Manifold -Exhaust gaskets are needed between the head and the exhaust manifold -Studs are usually threaded into the head instead of bolts -Exhaust manifolds direct hot gasses towards the exhaust system and are usually made of cast iron to hold up to the intense heat

37. Intake Manifold -Intake manifold gaskets provide a seal between the head and the intake manifold -Intakes are made of aluminum and sometime plastic that has smooth surfaces to help with air flow -Intakes sometimes have multiple runners to provide different lengths during different running conditions

38. Intake Manifold -Intake runners can just move air (direct injection) or they can run air/fuel mixtures such as older V8 engines