71' - FJ40 Exhaust Manifold (1 Viewer)

[QB1]

Curious if anybody can tell me what the part is that I am holding inside of the exhaust manifold...? Is it supposed to move on the spindle? Can it be removed...?
Thanks...

 

[Jdc1]

It’s supposed to be closed until the engine is to operating temp and then open. It also contributes to cracked intakes. You can remove it and plug the spindle holes. Depending on where you live you might need to add a fluid heat riser to aid your cold starts.

 

[ryanwk628]

I ended up afixing mine in the warm position because it was totally shot and I wont be driving my rig in the cold.

Thanks, a very good thread I referenced before doing this. I think when you say closed you're describing cold but I welded the valve in the hot position, which is the position on the right in the picture below. Logic being I don't intend to drive my 40 in the winter and it has been operating the last few years with it flapping in the breeze. Headers don't use a heat riser and work just fine. If I welded it in the cold position it would be an obstruction to smooth exhaust flow and continue to warm the carb beyond what was intended possibly cracking the intake. I feel like removing it all together would create a void in the elbow that would be a detriment to exhaust flow where you would have turbulent air swirling in the corner and continue to heat the intake. So I welded it in the position it was designed to be in when hot.
View attachment 1392794

Pighead's reply in post #21 is more inline with my thinking: "The manual makes for funny reading in a few places, I figger it was just a bad day at the translator's typewriter..." hahaha.

EDIT:
I drew this cross section to illustrate what I was concerned about if I removed the riser all together. I think it would both impact flow and continue to warm to intake without a block off plate.
View attachment 1392814

 

[thebigredrocker]

It helps fuel atomize in cold weather. It's not too difficult to fix. Here's a link

Manifold Heat Control Valve??

My flapper was loose on the shaft so I pulled it apart. Does the bend in mine look correct? I temporarily re-installed the flapper in the same orientation I found it. This would be cold Here's hot

forum.ih8mud.com

 

[QB1]

Thank You #thebigredrocker...great info...
Much appreciated!