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In a message dated 11/14/13 18 58 15, SOBill@aol.com writes:<BR>
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<BLOCKQUOTE CITE STYLE="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px" TYPE="CITE"></FONT><FONT COLOR="#000000" FACE="Geneva" FAMILY="SANSSERIF" SIZE="2">If you use a non-hat thermostat with a non-bypass pump (Wieand), water will not recirculate thru the block and the engine will warm up somewhat slower.<BR>
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More to the point, initially water will stagnate and cavitate as the water pump churns away with no possibility of water flow. You will also get hot spots in the engine as it heats up unevenly, with steam pockets potentially forming. One of the coldest points in the system will be right where the thermostat is, so heat will have to radiate through the water in order for the thermostat to open (rather than hot water flowing to reach it).<BR>
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Then, when the thermostat finally opens up, scalding hot water flows forward, and ice-cold water is sucked into the engine. WHAM! Thermal shock, big-time! That cold water will reach the thermostat, and will only be partially warmed, so the thermostat will close again, and the cycle will repeat several times. This is very hard on the block, apparently.<BR>
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In short, it's a very stupid thing to do. Now, if the bypass orifice is blocked off only partially, and a bypass pump is used, the probably won't be nearly as bad. The engine should heat up evenly, as it would with a normal cooling system setup. When the thermostat opens, though, a certain percentage of the water will continue to circulate through the block instead of going to the radiator.<BR>
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This isn't a terrible thing. For if you look closely at the 351C thermostat 'hat' you'll see it is a fair bit smaller than the orifice that it is designed to block. It never closes it off completely, and instead allows some water to circulate through the engine, following the same model (in a different way) as the other Ford families of V-8s (which use a small external rubber hose to accomplish with the 351C does with an internal passageway).<BR>
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Mike<BR>
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