Head gasket
(→Symptoms of a blown head gasket) |
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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. | 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 then embedded 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 | + | To take full advantage of copper head gaskets, you have grooves machined into the block or the head. Stainless steel wire is then embedded 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 reusable. |
Gasket Works makes a stainless steel o-ring that is only 0.004" thick and eliminates the need to groove the block or head. See: http://www.headgasket.com/images/olympic%20rings.jpg . | Gasket Works makes a stainless steel o-ring that is only 0.004" thick and eliminates the need to groove the block or head. See: http://www.headgasket.com/images/olympic%20rings.jpg . | ||
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*Pre-fit the head gasket. | *Pre-fit the head gasket. | ||
*Don't use sealant unless the manufacturer explicitly specifies it. | *Don't use sealant unless the manufacturer explicitly specifies it. | ||
| − | *Follow specific torque settings and bolt-tightening sequence perfectly. Re-torque as | + | *Follow specific torque settings and bolt-tightening sequence perfectly. Re-torque as specified. |
*Replace both at the same time, even if only one has blown. | *Replace both at the same time, even if only one has blown. | ||
*Oil the tips of the cylinder head bolts with light oil. ''(confirm this, and expand)''. Also, you can use a little bit of oil on the underside of the bolt, to aid getting the proper torque reading. | *Oil the tips of the cylinder head bolts with light oil. ''(confirm this, and expand)''. Also, you can use a little bit of oil on the underside of the bolt, to aid getting the proper torque reading. | ||
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