rons49 Posted July 9, 2011 Share Posted July 9, 2011 If the spring on a heat riser is disconnected, will the heat riser "fall" into an open or closed position? Link to comment Share on other sites More sharing options...
ply33 Posted July 9, 2011 Share Posted July 9, 2011 I suppose it might be different on different makes of cars (use of bi-metallic coil versus a thermally sensitive spring) but on my car the spring weakens as it gets warmer allowing a counter weight to pull the flap in the exhaust manifold to the warm position. So if the spring is removed and the counter weight is left on, it should move to the hot position. Link to comment Share on other sites More sharing options...
rons49 Posted July 9, 2011 Author Share Posted July 9, 2011 What Position is the valve in when cold and the weight is up, is it closed or open.Does closed mean that gases are diverted to the intake or to the tailpipe? Why would you tie the weight in the up position if that is where the spring places it when cold, ie, diverting gases to the intake? Why can you not just release the spring and let the weight drop for all driving in warmer climates? Members in another forum say that you must tie(wire) the valve weight from falling. Also on this forum in a March thread. This seems counter to what is needed. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted July 9, 2011 Share Posted July 9, 2011 The weight is supposed to be held by the spring. If the spring is missing it will rattle around which makes an annoying noise. The cure is to wire it open so it cant rattle.When the valve is closed (cold] the hot exhaust is diverted against the bottom of the intake to warm it and vaporize the cold fuel. As the engine warms the spring relaxes allowing the valve to open and the exhaust to go out unimpeded.If a car sits for a long time the valve can rust shut in the cold position.The best thing to do is fix it the way the factory intended. It will make a significant difference in the way your car runs when it is warming up. Link to comment Share on other sites More sharing options...
rons49 Posted July 9, 2011 Author Share Posted July 9, 2011 Thanks Rusty, Mine works well, but another fella on another forum had a problem with a broken spring and was told to wire the valve with the weight to the top.That would be where the valve is set on a cold engine with spring tension. If he did that I suspected he was in for trouble and I was right. Later,on a drive, his carb vaporized the fuel instantly, but his feet worked well. Link to comment Share on other sites More sharing options...
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