Head gasket
(→When replacing a blown head gasket) |
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| − | + | Cylinder head gaskets provide the critical seal between the engine block and the cylinder head. They seal all of the combustion chambers, and prevent coolant and engine oil from leaking into the cylinders. | |
==Different types of head gaskets== | ==Different types of head gaskets== | ||
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==Reasons why head gaskets fail== | ==Reasons why head gaskets fail== | ||
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| + | ==Head gasket re-torquing== | ||
| + | Head gaskets will typically need to be re-torqued. Copper head gaskets need frequent re-torqueing. Even head gaskets that say: "No re-torqueing necessary" may need to be occasionally re-torqued. | ||
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| + | Re-torqueing should be done when the engine is completely cool. | ||
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*Overheating, possibly from a blown hose, water pump, or thermostat. | *Overheating, possibly from a blown hose, water pump, or thermostat. | ||
*Engine pre-ignition or detonation. | *Engine pre-ignition or detonation. | ||
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==When replacing a blown head gasket== | ==When replacing a blown head gasket== | ||
*Check to make sure the heads and block are straight. If they're warped, you could easily end up with another blown head gasket. This can be done with a straight edge and a feeler gauge. This is also a good time to check for cracks. This is especially important if using a thin gasket. The thicker gaskets are made to compensate for low spots on the deck. | *Check to make sure the heads and block are straight. If they're warped, you could easily end up with another blown head gasket. This can be done with a straight edge and a feeler gauge. This is also a good time to check for cracks. This is especially important if using a thin gasket. The thicker gaskets are made to compensate for low spots on the deck. | ||
| − | *Prep the surface | + | *Prep the surface. Mating surfaces should be smooth, clean, and dry. Can be cleaned with brake cleaner, or denatured alcohol ''(confirm)''. |
*Chase the bolt and stud holes. Clean with compressed air. | *Chase the bolt and stud holes. Clean with compressed air. | ||
*Pre-fit the head gasket. | *Pre-fit the head gasket. | ||
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*Follow specific torque settings and bolt-tightening sequence perfectly. | *Follow specific torque settings and bolt-tightening sequence perfectly. | ||
*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)'' | ||
| + | *Sometimes a sealant will need to be used on the head bolts, as they may intersect the water jackets, and be exposed to engine coolant. | ||
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| + | ==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. | ||
| + | However, copper head gaskets have superior thermal conductivity, thought to stabilize head and block temperature, and provide elasticity and strength. | ||
==Suppliers of head gaskets== | ==Suppliers of head gaskets== | ||
*Fel-Pro | *Fel-Pro | ||
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