maar dat is geen onderbouwing andré,
laten we eerlijk zijn,
Dus wat is nou de reden om het niet te doen...
hieralvast een leuk stukje:
Replacement guides come in various alloys and varieties including bronze, cast iron and powdered metal. Phosphor/bronze, silicon/aluminum/bronze and manganese/bronze are generally more expensive than cast iron but are harder and usually provide superior wear resistance. With leaded gasoline, bronze guides typically lasted 3 to 5 times longer than cast iron. But with unleaded gasoline the difference in longevity between cast iron and bronze is not as great according to one supplier of bronze guides. However, bronze still provides superior heat transfer, resists seizing and can handle closer tolerances (which improves valve life and reduces oil consumption). That is why thick wall bronze guides are preferred by many performance shops.