Head gasket
(→Head gasket repair additives) |
(→Copper head gaskets) |
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====Copper head gaskets==== | ====Copper head gaskets==== | ||
| − | Copper head gaskets are typically less forgiving. They're commonly used in high-performance applications. They are re-usable, although they have to be re-annealed. They seal combustion well, but they are prone to leaking coolant and are less forgiving to imperfections in the head and deck surfaces. | + | Copper head gaskets are typically less forgiving. They're commonly used in high-performance applications where extreme cylinder pressures will be encountered, such as very high static compression ratios on naturally-aspirated motors or where superchargers or turbochargers are used. They are re-usable, although they have to be re-annealed. They seal combustion well, but they are prone to leaking coolant and are less forgiving to imperfections in the head and deck surfaces. |
| − | To take full advantage of copper head gaskets, you have grooves machined into the block or the head. Stainless steel wire is | + | To take full advantage of copper head gaskets, you have grooves machined into the block or the head. Stainless steel wire is then imbedded into the groove so that it sticks up slightly above the block deck or head surface. Although copper is a relatively soft material, there is a limit to which it can be compressed by an o-ring. Generally speaking, this limit is about 10% of the gasket thickness. For instance, with a 0.030" thick gasket, you would want to limit the height of the o-ring to about 0.003" above the head or deck surface. For a 0.060" thick gasket, about 0.006" and so forth. If the groove is cut into the head for the wire, then a "receiver groove" is machined into the block. If the groove is cut into the block deck for the wire, then a receiver groove is machined into the head surface. When the head is bolted to the block, the wire pushes some of the copper up into the receiver groove and makes a very effective seal. ''(confirm and expand)''. You'll also need a good sealer around the water passages. If copper head gaskets are used with an o-ring, they are NOT reuseable. |
However, copper head gaskets have superior thermal conductivity, thought to stabilize head and block temperature, and provide elasticity and strength. | However, copper head gaskets have superior thermal conductivity, thought to stabilize head and block temperature, and provide elasticity and strength. | ||
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