exhaust "damper"?
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exhaust "damper"?
I have a 1987 f150 4x4 351w,c6 my question is on the driver side there is a "valve" on the exhaust between the manifold and the y pipe will the valve be open if the vacuum line is disconnected or does it need vacuum to open? thanks for any input.
craig.
craig.
More Turbo
Joined: Dec 2003
Posts: 616
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From: Missouri - Lake of the Oz
exhaust valve
The vacuum modulated valve on your driver side exhaust head pipe closes with vacuum applied during cold engine start to force the hot exhaust gas through the crossover in the intake manifold, across the bimetal pulldown spring attached to the choke. This is done to more quickly warm up the choke mechanism so that it will open & to help get the engine into its "warm" mode.
If the vacuum line is loose or the diaphragm is damaged then the valve will stay open & your engine will not warm as quickly, thus your choke will not open as soon. The engine will run rich & you will experience all the problems associated with that.
Replacement of the valve (if you find this to be needed) is easiest if you first soak the threads with a good quality rust penetrant, allowing it a little time to work. Then use an impact wrench - if you have access to one - to remove the nuts & / or studs that hold the assembly together.
When reassembling, use an anti seize compound on the threads so that the job is easier the next time.
dn.
If the vacuum line is loose or the diaphragm is damaged then the valve will stay open & your engine will not warm as quickly, thus your choke will not open as soon. The engine will run rich & you will experience all the problems associated with that.
Replacement of the valve (if you find this to be needed) is easiest if you first soak the threads with a good quality rust penetrant, allowing it a little time to work. Then use an impact wrench - if you have access to one - to remove the nuts & / or studs that hold the assembly together.
When reassembling, use an anti seize compound on the threads so that the job is easier the next time.
dn.
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thanks donnor for your help
I was asking because the vacuum was disconnected and the valve itself was "unhooked" so now I am guessing the valve was closed all the time. I will reconnect the valve (the steel arm that goes from the diaphram to the valve)and not bother with the vacuum line(usine edelbrock carb and filter)
I was asking because the vacuum was disconnected and the valve itself was "unhooked" so now I am guessing the valve was closed all the time. I will reconnect the valve (the steel arm that goes from the diaphram to the valve)and not bother with the vacuum line(usine edelbrock carb and filter)
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