Should i remove the heat riser ??
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Laughing Gas
Joined: Apr 2003
Posts: 936
Likes: 25
From: La Ronge Saskatchewan
Should i remove the heat riser ??
I pulled the intake and exhaust off tonight to do some detailing and had a hunch the heat riser valve was broken and staying in the "valve closed position".
Sure enough the valve stays closed (the bimetallic spring is broken).
Maybe thats why the 223 won't chirp the tires
Anyway, my questions is should i just remove the flapper valve from the exhuast manifold ? The truck has a manual choke for cold weather.
Is this valve "choking off" my exhaust by staying closed ?
If i removed the flapper valve would the engine warm up properly in cold weather ?
Sure enough the valve stays closed (the bimetallic spring is broken).
Maybe thats why the 223 won't chirp the tires
Anyway, my questions is should i just remove the flapper valve from the exhuast manifold ? The truck has a manual choke for cold weather.
Is this valve "choking off" my exhaust by staying closed ?
If i removed the flapper valve would the engine warm up properly in cold weather ?
Senior User
Joined: Feb 2004
Posts: 346
Likes: 0
From: Raleigh, NC
I am about to do that myself. I found my valve to be 'frozen' as I am unable to move it by hand. I'm hoping that I can free it up. Had not thought of taking it out. The shop manual says that an inoperative or sticking exhaust control valve will cause a rough engine idle and poor acceleration. Hmmm, I 've got both of those....
The purpose of the valve is to allow warm exhaust gases to warm the incoming fuel so that it atomizes properly in the carb. Like you, I'm thinking that the choke will cover for it's absence when the engine is cold.
The purpose of the valve is to allow warm exhaust gases to warm the incoming fuel so that it atomizes properly in the carb. Like you, I'm thinking that the choke will cover for it's absence when the engine is cold.
Fleet Mechanic
Joined: Jun 2004
Posts: 1,771
Likes: 39
From: Minnesota
The choke will work she might be a little cold blooded though. The idea is for the exhaust to warm the intake up quickly. Without that extra heat she might take awhile to heat up. Could you controll the system manually with a choke cable. I will have to look at mine once I get her started this weekend.
Senior User
Joined: Aug 2001
Posts: 126
Likes: 1
From: Northwest
I don't think the riser valve can choke off the exhaust unless it comes loose and gets forced down the pipe. Mine was loose and rattling around and mostly allowing exhaust to blow out its pivots. I removed it and plugged the holes and all is well. Getting the intake and exhaust split to get the valve out was a chore! Without the valve you might get into vapor lock problems if you live in Phoenix and the intake gets too warm. I also installed an insulating spacer under the carb and haven't had any problems.
J
J
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Laughing Gas
Joined: Apr 2003
Posts: 936
Likes: 25
From: La Ronge Saskatchewan
Heya Starfox was the valve stuck in the open or closed position ?
If it was stuck in the open position then there is my answer i guess......no exhaust valve will result in poor acceleration and rough engine idle so i will not remove it.
If it was stuck closed then thats what i have too; mines not frozen/rusted it the spring just broke so the valve stays closed........but the engine runs okay.
If it was stuck in the open position then there is my answer i guess......no exhaust valve will result in poor acceleration and rough engine idle so i will not remove it.
If it was stuck closed then thats what i have too; mines not frozen/rusted it the spring just broke so the valve stays closed........but the engine runs okay.
Senior User
Joined: Feb 2004
Posts: 346
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From: Raleigh, NC
Well, to be honest, I don't know if it is open or closed. The truck is 'brand new' to me and I only just found out about the valve. Supposedly one can turn it by hand but I can't get the counterbalancer to budge and I don't want to force it with a tool. Do you happen to know if you can tell the orientation of the valve by looking at orientation of the counterbalancer?
If my new fuel pump comes in today I'll be firing it up this weekend. I expect removing the manifolds and addressing the valve will be one of my next steps.
If my new fuel pump comes in today I'll be firing it up this weekend. I expect removing the manifolds and addressing the valve will be one of my next steps.
Junior User
Joined: Aug 2003
Posts: 74
Likes: 0
From: Petaluma, California
My grandmas car was running terrible and the valve was stuck closed so I opened it and wired it open and her car ran alot better. Also dont know what kind of tranny you have but if you have a manual transmission you should be able to chirp the tires. 
Hope this helps,
Paul
Hope this helps,
Paul
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Senior User
Joined: Feb 2004
Posts: 346
Likes: 0
From: Raleigh, NC
Well I do have a 4-on-the-floor! 
I do see in the shop manual that there is a diagram of the valve and counterbalancer, but being a small image, and me being blind, it is difficult to figure.
From what I can tell - if the counterbalancer is vertically oriented then the valve is closed which permits warm exhaust to the carburetor. If the counterbalancer is horizontally oriented then the valve is open allowing the gases to run into the exhaust manifold. I seem to recall that mine was inbetween - so perhaps I'll have the 'best' of both worlds until I loosen it up.
I do see in the shop manual that there is a diagram of the valve and counterbalancer, but being a small image, and me being blind, it is difficult to figure. From what I can tell - if the counterbalancer is vertically oriented then the valve is closed which permits warm exhaust to the carburetor. If the counterbalancer is horizontally oriented then the valve is open allowing the gases to run into the exhaust manifold. I seem to recall that mine was inbetween - so perhaps I'll have the 'best' of both worlds until I loosen it up.
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Junior User
Joined: Apr 2004
Posts: 96
Likes: 1
Removing the heat riser will result in a slower warm up time. Possibly increased stalling and reduced power until engine is completely warmed up. If you unstick the valve and don't replace the spring, you won't know whether the valve is open or closed at start up or after the engine is warmed up. Best bet is to try to get it functioning properly. Ford would not have spent all that money on heat risers unless they were required.
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