1 / 25

Cylinder Head: Valve Springs, Valves, and Valve Seats

This chapter focuses on the analysis of wear and damage to valves, springs, and valve seats, as well as the theory and repair techniques related to these components. The reassembly of the cylinder head is also covered.

nterry
Download Presentation

Cylinder Head: Valve Springs, Valves, and Valve Seats

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 8 Cylinder Head: Springs, Valves, and Valve Seats

  2. Objectives • Analyze wear and damage to valves, springs, and seats • Understand theory related to valves, seats, springs, and other related parts • Select and perform correct repair • Reassemble cylinder head

  3. Valve Springs • Pressure on valve spring comes from three sources • Spring • Pressure of combustion • Seat angle

  4. Valve Spring Inspection • Visual inspection • Spring squareness • Free length • Spring tension

  5. Pushrods • Transmit motion from lifters to rocker arms • Hollow to allow oil to be transferred to rocker arms • Holes in cylinder head act as guide for push rod

  6. Pushrods

  7. Rocker Arms • Shaft mounted or stud mounted • Iron, cast iron, or stamped steel • Different ratios (longer length) • Increasing ratio causes more movement of valves • Makes it possible to have smaller cam lobes

  8. Rocker Arms

  9. Valve Damage • Wear on valve stem • Valve burning • Hoop stretching • Valve oxidation • Incorrect seating due to incorrect valve lash

  10. Exhaust and Intake Valves • Intake valves are generally larger than exhaust • High carbon steel and tempered to resist corrosion • Valve stems are typically chrome plated • Some are sodium filled

  11. Grinding Valves • Chamfer valve tips • Should be done before grinding valve • Grinding stem tip • .010" to .015" should be removed from valves • Grinding valve face • 1º interference angle

  12. Grinding Valves

  13. Grinding Valve Face • First dress grinding stone • Adjust chuck to grab valve on unworn section of valve stem • Do not allow neck of valve to contact grinding stone

  14. Grinding Valve Face • Adjust grinder to proper valve angle • Grind only enough to remove any area of valve face that is worn

  15. Valve Seats and Service • Most valve seats are integral and part of the cylinder head • Integral seats are induction hardened to reduce seat wear • Operate approximately 150º cooler than replaceable valve seats

  16. Grinding or Cutting Seats • Most are finished to 45º or 30º • Seats are serviced with either grinding stones or carbide cutters • Pilot is installed into valve guide to center cutter

  17. Grinding or Cutting Seats

  18. Grinding Seats • Advantages of grinding • Produces a smoother seat than cutting does • Can be used on extremely hard seats • Grinding stones must be dressed to true them to proper angle • Valve seat runout should be less than .002"

  19. Grinding Seats

  20. Carbide Cutters • Advantages to carbide cutters • Quiet • Remain clean • Angles remain true • No grinding dust

  21. Carbide Cutters

  22. Seat Refinishing Angles • Sometimes all three angles are cut at once, which also cuts seats to correct height. • Typical three angle valve job • Face angle • Top angle • Throat angle

  23. Seat Refinishing Angles

  24. Reassembling Cylinder Head • Recheck installed height of valve spring • Grind tip or install new valves to achieve proper specification • Install valve shims under springs

  25. Reassembling Cylinder Head • Thoroughly clean all guides • Lubricate valve stems • Install guide seals • Install valve, spring, retainer, and keepers

More Related