Engines: Engine Rebuilding: Engine disassembly
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Topic IntroductionHelp

Disassemble valve train

Summary
The objective of this procedure is to show you how to disassemble and remove the valve train. Use an organizer tray to ensure that everything goes back into the exact position that it came from.

Part 1. Preparation and safety

Objective

Disassemble and remove the valve train

Personal safety

Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

If you are not certain what is appropriate or required, ask your supervisor.

Safety check

Points to note


Part 2: Step-by-step instruction

  1. Remove rocker arms
    The valve train is made up of all of the parts that are associated with the opening and closing of the valves. The valve train controls the mechanical timing of these events. The camshaft, lifters, pushrods, rocker arms, valve springs and the valves themselves all make up the valve train.
    Start with the rocker arm nuts which are at the fixed pivot points of the rocker arms. If the engine has rocker shafts that the rocker arms are mounted on, the entire shaft is usually unbolted and lifted off as one piece. As the rocker arms come off, make sure the pivot ball that is under the rocker nut stays with its respective rocker arm.
  2. Use an organizer tray
    It's very important that as you take the valvetrain apart, everything that can be re-used has to be organized so that during reassembly it goes back into the exact position that it came from. If parts are not matched to their original placements, with their companion parts, excessive wear will occur. Some tools suppliers have special valvetrain organizer trays for this purpose. New components should be uniform in size and, of course, don't need to be matched.
  3. Remove pushrods
    As you remove the pushrods, make sure the upper end stays in the up position. If you reassemble them upside down or get them mixed up, they will wear out a lot faster.
  4. Remove valve lifters
    There are special pick tools that make it easier to pull out clean valve lifters, but you can also use a small flat head screw driver to do this.
    If any or all of the lifters are gummed up with dirty oil and don't want to come out, leave them where they are. They can be removed from the bottom after the camshaft has been removed.
    Unless they are obviously unsalvageable, put them all in the organizer tray for now. They will be assessed later to see if they can be reused or not.