The Stovebolt Site Forums The Shop Area Engine Shop What is sticking out of my exhaust manifold?

Uh...what the heck is this sticking out of my exhaust manifold. And what did it do? See pic here. This is on my '69 L6 C-10.

Its the counter weight on the preheater that is spring loaded. when cold it tightens up and closes the exhaust off directing the heated air back into the intake, when things warm up it opens and allows all the gasses out the exhaust pipe.

It's called a heat riser,it opens and closes a valve in the exhaust manifold to warm up the intake manifold and the carb so they don't freeze up when the engine is cold and the air is cold. That coil is like a thermostat and and is whats called a bimetalic coil it will coil tighter and looser when it cold or hot.The iron thing you see is the counter weight so the spring does not have to work that hard to open and close.Most of the time they are rusted and don't work ,but you should get it to work right.I took mine and tapped it lightly with a small hammer and keep trying to get it to move and at the same time sprayed it with liquid wrench it took about a week to get it free than I bought a new spring coil fron Clasic of America now it works .


Pete

Thanks, guys. I found it yesteday when I was feeling around for a nut I dropped. When I touched it, it moved and I thought, "What the heck?!?!"

Pete,it actually turns freely. Thanks for the vendor tip.