The Stovebolt Site Forums The Shop Area Engine Shop Louder after switching manifolds?

So I have a 56 235 and I swapped the 216 manifold that was on it for a correct 235 manifolds. It seems louder like my manifolds are going to explode. My heat on/ off assem in the exhaust manifold doesn't spin free so I think I have it set to heat off. Is it a manifold leak ?or Mabey the heat on/ off causing it to sound loud ( sounds like its coming from the engine not the exhaust pipe) if my on off is stuck would it be better to run it on or off? Mostly off? Thanks for any suggestions

Did you use the alignment rings that go into the head? If the heat riser is closed and you have a leaking manifold gasket things would be loud.

The heat riser should be spring loaded. Its a heat sensing spring that relaxes as it heats up. During a cold start, the heat riser valve would be closed, this deflects exhaust gases up under and around the intake manifold to aid in warm up. As the engine begins to warm, the spring starts unwinding thus shutting the heat valve so the exhaust gases now pass directly out the exhaust manifold.

You should not hear any difference when the valve is operating correctly. What you may have is a leaking gasket or improperly tightened gasket between the two manifolds.

As Don as has stated, you need locating rings on the intake to locate the ports to the head. You should also have a gasket in there as well. You should snug the bolts to the head before tightening the bolts holding the intake to the exhaust. Once you have everything snugged up, then pull the manifolds together and finish tightening the bolts to the head.

It rarely works tightening the manifolds together then installing them.

Joe

i did tighten after attaching then to the head. i pulled my carb today and noticed my carb to insulator was a 216 gasket, and the holes are diffrent then 235. i orderd a new gasket for the 235. is there a gasket that goes between the insulator, and the intake manifold?