Head gasket
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===Aluminum cylinder heads=== | ===Aluminum cylinder heads=== | ||
| − | Though aluminum is lighter than cast iron, it expands | + | Though aluminum is lighter than cast iron, it expands twice as fast. This quicker cycle of expansion and contraction stresses head gaskets. To handle this, a non-stick coating is often applied to the gasket, like Teflon or molybdenum. |
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| + | Many OEM manufacturers are using graphite head gaskets on iron blocks with aluminum heads to help compensate for different coefficients of expansion between the two differing metals. Graphite head gaskets may have multiple types of coatings in different areas to facility sealing (silicone) and expansion (Teflon/molybdenum). | ||
With iron heads, a product can be applied for the opposite effect. Silicone, Viton, or other fluoroelastomer sealants are applied to '''increase''' the pressure between the iron heads and the iron block. | With iron heads, a product can be applied for the opposite effect. Silicone, Viton, or other fluoroelastomer sealants are applied to '''increase''' the pressure between the iron heads and the iron block. | ||
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