03/31/2026
When the valve lash is set correctly, the engine runs more efficiently because the valves open and close at the right times. That means better combustion, and so you get a more complete burn of fuel, which leads to improved fuel economy. So, yeah, it can have a pretty noticeable effect in the long run.So, the overhead adjustment on the DD15 is crucial because it ensures that the valve lash is set correctly. If the lash is off, the engine can suffer from poor performance, reduced fuel efficiency, increased emissions, or even excessive wear on the valvetrain. So, basically, it helps keep the engine running smoothly and reliably over time.