Editing Ford CVH engine (section)

===Sludge===
The camshaft is oiled by small holes in the cylinder head casting next to the lifter bores. These holes are prone to blocking up with [[oil sludge]] if the engine is not serviced regularly, starving the camshaft of oil. The CVH is known for producing excessive sludge if the service schedule is ignored or if poor quality oil is used. The cause is the design of the crankcase ventilation circuit, which Ford revised several times over the engine's lifetime but never completely cured. Due to this, camshaft and tappet wear problems are common. A worn camshaft can cause heavy clattering and ticking from the engine's top end, especially at high engine speeds.<ref name="gomog-hist"/>