Whats this - Exhaust manifold lever???

[igasper10]

I found a spring-loaded lever of some sort on the right side manifold, just below the Y pipe. Anyone know what this is for???

ian -

 

[paul67]

Heat riser control valve.

 

[Stallion]

Maybe you're talking about the resurculation valve for the exaust for emissions? I'm not sure. Any pictures of what you're talking about?

TR

 

[Stallion]

Heat riser control valve.

Oh, I missed this post when I was posting.

Is this control valve just to warm up the engine a little faster? Is what this is used for? Because I remember there being something on the exaust manifold that brings heat to the engine when it's warming up. Not sure. Any ideas?

 

[Enigma]

Paul79 is correct. It is controlled via a temperature switch located usually around the hot coolant return on the intake maifold.

The switch controls the vacuum to the heat riser valve.

While the engine is cold the valve is closed and when the motor is at temp it is open.

Enigma

 

[Stallion]

Paul79 is correct. It is controlled via a temperature switch located usually around the hot coolant return on the intake maifold.

The switch controls the vacuum to the heat riser valve.

While the engine is cold the valve is closed and when the motor is at temp it is open.

Enigma

Why would the valve be closed when the engine is cold? Wouldn't it be open to let the hot air up to warm the block?

 

[Enigma]

It would be closed so that the hot gasses will be forced
through passages in the right cylinder head and the intake
manifold. The heat warms the carburator which improves the
vapourization characteristics of the fuel.
When the engine is at operating temperature the hot gasses are not needed anymore , so the valve opens allowing the exhaust gasses to pass to the exhaust system.

Enigma

 

[mvftw]

I'm putting in true duals tomorrow (with stainless steel flowmaster 50's) and out comes that heat riser...:cool

 

[Stallion]

Okay, thanks for the explanation, Enigma.

Good luck with the true duals!! That will surely sound very nice when it is done. Have fun !!

TR

 

[igasper10]

THANX!!!

Thanks for all the replies. I'll be putting on shocks & u-joints today on my 74 project. Ball joints next week.