Posted by David Sheman on Friday, October 17, 2003 at 10:27AM :
In Reply to: A thought just occured to me posted by Clint Dixon on Thursday, October 16, 2003 at 10:40PM :
If I understand Bob correctly, the restrictor plate is between the carb and manifold, sandwiched between two gaskets. At this location, it would increase the manifold vacuum at open throttle settings but would not increase the vacuum seen by any carb ports that open between the throttle body and that restrictor plate. I'm not familiar with this installation, but in general various types and thicknesses of gaskets are used between the carb and the manifold to control the amount of heat that gets up into the carb. One wants enough heat to prevent icing but not enough to cause vapor lock. Since the steel plate is acting as a restriction in the air flow, I can only guess that either A) it shouldn't be there, B) it has something to do with the velocity governor, or C) somebody put it there to make the vacuum-powered wipers keep working at full throttle. Also, there used to be various alleged gas-saving gizmos that inserted in that position. One I remember was a thick fiber gasket with a dome-shaped wire screen in the hole. The screen was supposedly coated with platinum which was supposed to somehow make the fuel vaporize better. I don't know that it worked, but it did keep small parts and tools from falling into the engine.
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