Need help with my exhaust manifold setup

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Dec 9, 2018
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Upstate NY
I believe the exhaust manifold heat riser should work like this:

s1.jpg

At my setup, the heat riser was set as in picture B in the cold engine.
Also, the heat riser controller spring is on the right side of the pipe (most pictures show it on the left side).
At first, I thought someone reinstalled it on the right side...but there is no evidence on the left side of the pipe (see picture) it looks like this setup from the monifacture... Do I miss something?

IMG_8102.jpeg
IMG_8103.jpeg

 
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Jan 6, 2003
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I have a 75 and mine is setup the same as yours. The spring should open when the engine is warm, but a lot of people mention that they get stuck in the cold position and end up cracking the intake manifold because of the heat. You could check to see if the valve moves freely and that it opens when hot or just check the position when the engine is hot. Since i live in a warm climate I clamped mine shut in the closed position and bought the block off plate from cruiser outfitters, I just haven't gotten around to installing it yet
 
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Joined
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I have a 75 and mine is setup the same as yours. The spring should open when the engine is warm, but a lot of people mention that they get stuck in the cold position and end up cracking the exhaust manifold because of the heat. You could check to see if the valve moves freely and that it opens when hot or just check the position when the engine is hot. Since i live in a warm climate I clamped mine shut in the closed position and bought the block off plate from cruiser outfitters, I just haven't gotten around to installing it yet
It moves freely but the spring keeps valves as in my picture B. I just install a "new" engine (never start yet), it is a cold engine and it is in an "open" position, all flow comes directly to the exhaust pipe. I guess if I start the engine... spring will heated and move the valve plate to position A (on my picture)?

This is what I find from other setts up:
https://forum.ih8mud.com/attachments/bushing2-jpg.178856/

bushing2.jpeg


and my valves plate looking in opposite directions.
 
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actually, I find this video:



it shows exactly as my is setup. But now I totally lost.. how it actually works...
they said when the engine cools down it comes back to the "close" position... but what about when the engine is running and still hot it still heats top?

Edit: I was wrong.. this video is from the bottom... what is make sense...
But my setup is doesn't...
 
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Upstate NY
I have figured it out...
Someone loses the tension (for reason) of the spring to one rotation it keeps the valve plate permanently in a "hot" position
If I flip it back plate stay in the "cold" position but it is not moved even I heat it up. This is why someone keeps it at the "hot" position.

Before....

IMG_8121.jpeg


Heat it up ..no move....

IMG_8122D.jpeg


Tighten the spring with one revolving (anti-clockwise)..

IMG_8123D.jpeg

IMG_8124D.jpeg


The question is why is still not moving when I head it up in this position... maybe bad spring?
 
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Maybe try taking the spring off and heat it to see if it expands/contracts without any resistance. Possibly the counterweight is in the wrong position and the spring is not strong enough to over come the imbalance.
 

OSS

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The machine shop that used to do all the manifold rebuilding for tlc4x4 in Southern California would remove that flapper heat control valve from every manifold that went through their shop - whether it was requested or not.
I was told that they can and do stick in the Cold position which overheats the manifold & cracks it.
My intake manifold was cracked (2F FJ60) which they fixed by welding.
 
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Do you think it is better to keep it permanently in the "hot" position or remove it completely?
Removing it completely will require some extra work ... cover the pipe holes and probably add an extra plate to the manifold.
But it will keep the manifold relatively warm/hot?
Keeping it permanently in the "hot" position is easy.. just by turning the spring opposite to the heat direction.
But doing this will probably keep the manifold relatively cold.
 

brian

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Remove it completely.
The worst that happens, it runs like crap in the cold for a few minutes till the engine comes up to operating temp. The manifold will warmup.
 

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