How to Adjust Rockers Arm

A very complex part of the engine is the valve trains. It has dozens of movable parts and all these parts should move in harmony, in speed and at high temperatures. The clearances in it should be as thins as paper. When the metal heats up, it expands and thus it becomes difficult to maintain the clearances. To top it the stress on the valve springs and mass makes it more difficult to maintain these clearances, and leads to failure of the engine if there is no built-in ’slop’. To ensure its functioning effectively, the valve stem and the rocker arm adjustment is necessary. It helps in preventing any stress building up on the valve train. Learn how to adjust rocker arms of the engine to avoid any stress on the valve train, and affect its functioning.

A couple of tools will be required to adjust the rockers arm. The list given below will help you gather these tools.

  1. A complete set of Sockets – Standards and Metric
  2. A complete set of box-end wrenches – Standards and Metric
  3. A complete set of Allen head wrenches

How to adjust rocker arms?

  • The cover of the engine’s valve has to be removed first. This will allow you to access the engine’s valve train.
  • Wrap some old rags on a screw driver and shove it in to the ‘oil drain back holes’ of the cylinder head. Clean it well.
  • Using a soft bristle brush, a screwdriver and paint thinner, clean all the left over oil in and around the engine’s valve train.
  • There is a bolt located at the center of the crankshaft pulley of the engine. Fix the right sized socket on this bolt.
  • Attach the cheater bar and the ratchet to this socket and using it try turning the crankshaft.
  • The crankshaft has to be turned until the dead center over the crankshaft meets the pointer on its block.
  • On the first number cylinder, there is an exhaust valve. In mostly all the V-Shaped engines, it is located in front of the driver’s seat.
  • Above the engine’s exhaust port is the exhaust valve, and just next to it is the engine’s intake valve.
  • Keep turning the crankshaft until it opens up the intake valve and again starts closing. When it starts closing again, it ensures that the engine’s exhaust valve is closed completely.
  • To loosen the rocker arm completely, you will have to back-off the nut of the adjuster of the exhauster valve.
  • There is a pushrod below it. Hold it with your hand and twist this back & forth. Keep twisting the rod, and tighten the nut on the engine’s rocker arm. As the nut tightens, you would feel some sort of resistance while twisting the push rod.
  • While pushing the plunger of the hydraulic lift in the body of the lifter, turn the adjusting nut by half turn again. This adjustment will help in preloading the lifter and prevent any clatter on the valve train.
  • Again turn the crankshaft so that the intake valve of the engine closes, and the engine’s exhaust valve which you have just adjusted opens up and closes again completely. This will completely shut the engine’s intake valve.
  • Repeat the steps of turning the crankshaft and closing the valves with the rocker arm of the intake valve as well.
  • After you are done with one cylinder, move to the next cylinder that comes in the firing order of your engine. Repeat the same adjustments with this cylinder as well. Adjust all the cylinders as per their sequence in the firing order.

The procedure is lengthy and time consuming. You have to adjust all the cylinders one by one. However, it is very important to help prevent any stress building up on the engine’s valve train. You can take an expert’s help if you are adjusting the rocker arm for the first time. Also, refer to the user manual of your vehicle to understand the fittings of various parts of your vehicle’s engine before you start dismantling any part or nuts. Keeping the rocker arm in the right condition and adjustment, will prevent the early wear out of the valve train, and increase the life of your engine.


Related Content:

  1. How to Adjust Lifters
  2. How to Adjust Valves
  3. How to Adjust a Hydraulic Cutch
  4. How to Adjust a Carburetor
  5. How to Adjust a Door Closer

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