The Dodge Challenger Message Board

What is that "round" object on the passenger side exhaust manifold on my 1970 Challenger 383? Someone has taken a coat hanger and attached it to the part, not sure if that's to stop a rattle or what....Thanks!

That is a thing who's name escapes me for the moment but it is on a bi-metallic spring and it closes off the exhaust pipe on that side when cold so that when you start the engine the exhaust is forced through the bottom of the intake manifold and out into the exhaust manifold on the drivers side.

This is to aid cold starting and to warm the engine up faster.

As it warms up the thing opens and allows the exhaust on that side to work normally.

That is the theory. In practice the damn thing would stick and cause an obstruction. Most people cut them out (welding up the holes) or wire them open. If it has been open for a while it has probably rusted in place.

The "heat riser Valve" and bi-metal spring ? Does what Dave explained.

Follicly Challenged wrote:The "heat riser Valve" and bi-metal spring ? Does what Dave explained.

I'm keeping the hair but loosing the brain cells fast.