Head gasket
(→Removing an old head gasket) |
(→Steel (shim) gaskets) |
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Steel shim gaskets come in a variety of thicknesses as the name implies and range from .010 up to .080. Originally, the gaskets were of flat steel sheeting and went on to have an embossed surface. The embossing was strategically placed on the gasket surface around cylinder holes, water inlets, and outer surfaces. The embossing provided extra metal to fill in voids over the sealing surface when torqued into place. Shim gaskets could raise or lower compression in an engine without machining. They were the front runners of the now used fiber and non-ferrous metal gaskets. The term, "blowing a gasket" was common for top racers because they were using a very thin 10 or 20 thousandths shim gasket to raise compression, because of its thinness, the gasket would blow between two inner cylinders. They could stay in the race only as long as the gasket didn't disintegrate and expose the coolant passages to the combustion chamber. Engine builders of the day were often seen applying a couple coats of aluminum paint to both sides of a set of head gaskets to make them stick in place and seal the mating surfaces. The aluminum particles in the paint would fill in the voids in surfaces of the sand cast heads and block. | Steel shim gaskets come in a variety of thicknesses as the name implies and range from .010 up to .080. Originally, the gaskets were of flat steel sheeting and went on to have an embossed surface. The embossing was strategically placed on the gasket surface around cylinder holes, water inlets, and outer surfaces. The embossing provided extra metal to fill in voids over the sealing surface when torqued into place. Shim gaskets could raise or lower compression in an engine without machining. They were the front runners of the now used fiber and non-ferrous metal gaskets. The term, "blowing a gasket" was common for top racers because they were using a very thin 10 or 20 thousandths shim gasket to raise compression, because of its thinness, the gasket would blow between two inner cylinders. They could stay in the race only as long as the gasket didn't disintegrate and expose the coolant passages to the combustion chamber. Engine builders of the day were often seen applying a couple coats of aluminum paint to both sides of a set of head gaskets to make them stick in place and seal the mating surfaces. The aluminum particles in the paint would fill in the voids in surfaces of the sand cast heads and block. | ||
| + | ====MLS head gaskets==== | ||
| + | Sealant use may be required when retrofitting MLS head gaskets to engines which were not originally produced with MLS head gaskets, or when using MLS head gaskets on engines that have not been properly prepared. For proper coolant and oil sealing, MLS head gaskets require surface finishes of 30 RA (Roughness Average) or finer, this is because the elastomeric coating on the sealing surfaces of MLS head gaskets is approximately .001" thick which is too thin to seal leak paths in the peaks and valleys of rougher (RA30+) finishes. | ||
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| + | ====Steel Shim Head Gasket==== | ||
| + | Steel shim head gaskets are exactly what the name implies, simply a thin sheet of embossed steel with no sealers applied. Steel shim gaskets rely on the combination of increased localized pressure from the embossment (stamped ridges) much like MLS head gaskets, with the addition of a user applied sealant to insure liquid tight operation. | ||
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| + | ====Standard Copper Head Gaskets==== | ||
| + | Traditional flat copper head gaskets require the use of additional sealant for cooling and/or oil passage sealing. Similar to steel shim gaskets, traditional copper gaskets have no sealants applied. | ||
===Aluminum cylinder heads=== | ===Aluminum cylinder heads=== | ||
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