how important is the heat riser system?
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Senior User
Joined: Dec 2001
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From: b.c. canada
how important is the heat riser system?
77 f250
the flapper valve on the air cleaner remains closed when its warmed up. The problem is the switch located inside the air cleaner assemble. I can get this from ford but they wan't $40 for it. how nesasary is the entire system? Its disconnected right now but it will be getting cold in a few months. am i gonna have problems with the carb freezing up?
-gbm-
the flapper valve on the air cleaner remains closed when its warmed up. The problem is the switch located inside the air cleaner assemble. I can get this from ford but they wan't $40 for it. how nesasary is the entire system? Its disconnected right now but it will be getting cold in a few months. am i gonna have problems with the carb freezing up?
-gbm-
Posting Legend
Joined: Sep 2001
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You can get the switch out of any salvage yard vehicle. I have seen the same switch in Mopars. If you can find the right color dot it helps but most of the switches can be calibrated. A small amount of heat applied to the vent port fitting melts the thread locker and it can be adjusted.
The heated air intake is necessary to avoid carb freezups which could be already happening in your part of the world.
The heated air intake is necessary to avoid carb freezups which could be already happening in your part of the world.
Elder User
Joined: Dec 2004
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From: Springfield, OR
It helps alot with cold engine driveability, especially the first 5-10 minutes or so. Without it, the gas tends to pool in the intake manifold when it's really cold and you get stumbling and hesitation, then in an effort to keep the truck going you keep pumping the pedal and waste alot of gas. I was glad to see your post cause mine's broken too and now I know at least I can get them from ford. Can you tell me what they call it or what part number it carries ? thanks, don
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Senior User
Joined: Dec 2001
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From: b.c. canada
Originally Posted by T18skyguy
. I was glad to see your post cause mine's broken too and now I know at least I can get them from ford. Can you tell me what they call it or what part number it carries ? thanks, don
the air cleaner assembly on mine isnt stock being its a 4 barrel holley on a 351m. Its got a 77 code on the air cleaner and the PO told me it came off a 460, not sure if he meant car or truck. but the parts guy at ford looked at it and gave me the part number. CX1387 not sure if that works for your application or not.
ill scour the junk yards round here.
-gbm-
Post Fiend
Joined: Jul 2004
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From: Northern California
In extreme cold, the flapper will remain shut to prevent Carb Icing as well. Imperitive to get the right switch cause if it gets too hot and it remains shut, it can cause vapor lock in extreme heat.
I think local parts stores carry this too.
I think local parts stores carry this too.
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Senior User
Joined: Dec 2001
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From: b.c. canada
I looked on the original air cleaner assembly and It looked the same so i swapped out the vaccume switch. It is fairly warm around here right now and when I fire the truck up from cold the flap is open, with the old switch the flap remained closed all the time. I did check the new valve and it flowed freely. I guess i wont know if the system is working proper untill it gets a little colder.
-gbm-
-gbm-
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Posting Legend
Joined: Sep 2001
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It is difficult to diagnose the system but there are some instructions in Ford service manuals. At least if it does not work it usually will not strand you out in the middle of nowhere -unless, of course, the increased fuel consumption empties the tank... Sometimes that is the only way you know it is not working right. It will also lower performance but many people just think it is "cold weather".
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