Exhaust Flang
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Freshman User
Joined: May 2005
Posts: 25
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From: Racine, WI
Exhaust Flang
Hey guys was working on my truck with a buddy of mine and he pointed out that there is a flang on the header that has a weight on it that should swing down and open the flang once the engine is warm... Not sure what this is called "Exhaust Flang" was the best I could come up with... In any case mine is rusted and doesn't move.... I tried some WD 40 and a hammer but it appears to be bending more than loosening so I stopped.... Do I need to worry about this? How can I get it loose? Any ideas.... Any what is this actually called?
Shawn
Shawn
Roast em' if you got 'em
Joined: Mar 2005
Posts: 21,997
Likes: 9,886
From: Rio Rancho, NM
I'm not sure what it is called. It was designed to close the exhaust when the engine was cold to help with engine warming. As the engine and exhaust warms up the bi-metal spring on it is supposed to openthe flap (flange) and allow the exhaust to flow out. Most of the time when the rust up like that (and they all do) they rust inthe open position and are not a problem. If they rust closed then they are a restriction to the flow. I'm not sure how to go about telling which position it is in
Good luck
Bobby
Good luck
Bobby
old and in the way
Joined: Jul 1997
Posts: 5,921
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From: Lovely Hueytown Alabama
I think it's called a heat riser... and Bobby described its function perfectly
I'd start with some penetrating oil on both sides.. PB Blaster is my fav... but liquid wrench or some other will work... spray it a couple times a day and let it set...
now don't go flailing away with a heavy hammer... TAP it gently in each direction after the p.o. soaks for a while... might take a few days but it should work loose... if not you can buy replacements, but then you got to deal with those exhaust bolts/studs...
later,
John
I'd start with some penetrating oil on both sides.. PB Blaster is my fav... but liquid wrench or some other will work... spray it a couple times a day and let it set...
now don't go flailing away with a heavy hammer... TAP it gently in each direction after the p.o. soaks for a while... might take a few days but it should work loose... if not you can buy replacements, but then you got to deal with those exhaust bolts/studs...
later,
John
Hotshot
Joined: Oct 2004
Posts: 15,882
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From: Durham NC
That's correct it works like a thermostat to help warm up the engine by directing the exhaust thru a passage in the intake manifold under the carb and out the other side to warm the carb. Back in the day we would lock the butterfly open and block this passage with a piece of shim stock between the manifold and head to prevent this flow of exhaust gas since it had the negative affect of continuing to heat the carb and gas in the float bowl even when the butterfly was open reducing the power and sometimes contributing to vapor lock in the summer as well as producing a lot of sludge buildup in the passage that would cause backpressure when the butterfly was closed making the engine run rough and carbon sparkplugs and valves. Not one of Ford's better ideas IMHO.
Last edited by AXracer; Jul 6, 2005 at 02:22 PM.
Roast em' if you got 'em
Joined: Mar 2005
Posts: 21,997
Likes: 9,886
From: Rio Rancho, NM
I think most of them are seperate from the manifold itself and its not too big of a hassle to remove it. (well. the way my luck has been lately I'd break off both the studs, break a knuckle or two, drob my ratchet and socket and blacken and eye at break a tooth or two out, etc, etc, etc)
Bobby
Bobby
Hotshot
Joined: Oct 2004
Posts: 15,882
Likes: 88
From: Durham NC
If it is frozen open I'd leave it that way, next time (and there WILL be a next time the corrosive exhaust emmissions will see to it) it may stick shut and give you fits trying to figure out why the engine isn't running right.
