To ensure the proper operation of the spring washer that holds the rocker arm in place, it is locked on both sides by a washer.
With a complete overhaul of your engine, you can't leave anything to chance, the spring washer has lost its resilience over the years and, in many cases, the washers are worn.
For each rocker arm, you need two. If you replace all the washers on all rocker arms, you get a total of 16 parts.
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