This is my first post. Recently purchased a 1970 Skylark Custom with 69,000 miles. It has dual exhaust and when I started it the other day in the cold exhaust looked like it was just coming out drivers side. I asked a friend and they told me about baffle located below manifold, they said it was probably stuck. I checked it and it seems to move freely and it assume it opens when warm. I drove car to get warmed up and when you put your hand over exhaust pipes still seems to be more coming out of driver side. Is this normal????
i would think it would be the other way around if the flapper were stuck - the driver's side would feel weaker. The flapper has a coil of spring steel which keeps the valve closed, heating up the drivers side manifold where the heat pipe goes up to the air cleaner, to heat the air for cold starts in the winter. The valve pivot easily rusts and alot of times you see cars where the flapper part was cut out. ....Welcome Aboard :TU:
it is called a "heat riser" and they eventually seize up or the coiled spring breaks . most people just throw them out .
Mystery Dont worry about it , it is entirely normal, :laugh: The two pipes are not alike and there is almost always a difference. what you dont want is anti freeze, oil, bunches of black smoke, bunches of white smoke, ect, coming out of the pipes. :Brow:
exhaust problems Original exhaust pipes were double layered pipe for quiet operation. These pipes tend to bubble the inner layer and close off 75% of the flow. The exhaust backs up and passes under the carburetor and out the opposite pipe. This robs lots of power and overheats the carburetor and the fuel inside it. If this car has 69,000 orig. miles, it may also have original pipes. I would replace the pipes as far back as the cross member for the trans, if not all of it. By cutting the exhaust pipe at the first bend and at the flatened cross member area you may get a chance to see what I mean. Bent and squezed areas bubble first. Heat riser valves can stick firmly. They usually are closed or nearly so. If it will piviot, just wire it open (weight down). If not, cut the flap out or shaft also if necessary. I saved the housing so the pipe would fit onto the rounded lip, otherwise have a school machine shop make an exact copy "spacer" for free (and include a 2 1/2" hole) like I eventually did.
