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Name That Part

syndicate1

Contributor
Sr. Member
Joined
Feb 14, 2015
Messages
460
Can anyone name the original part attached to drivers side exhaust manifold/collector? And what’s it for?


5d590142004fceef5f41b6f3afd6df5d.jpg



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rydog1130

Contributor
Bronco Guru
Joined
Jun 19, 2014
Messages
4,188
Not sure what its called but my "guess" would be it maybe connected to the end of the air filter intake housing allowing it to open once it hit a certain temp... who knows....anyone else ????:??:?
 

Rightpace

Jr. Member
Joined
Aug 26, 2019
Messages
114
Thermostatic exhaust valve. Always heard them called butterfly valves. Bad about locking up closed, most people removed them and replaced with a spacer, seen them welded open to get rid of rattle in the late 70s and early 80s
 
OP
OP
S

syndicate1

Contributor
Sr. Member
Joined
Feb 14, 2015
Messages
460
Thermostatic exhaust valve. Always heard them called butterfly valves. Bad about locking up closed, most people removed them and replaced with a spacer, seen them welded open to get rid of rattle in the late 70s and early 80s


This one moves freely, thankfully it’s not locked up closed.


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mtp71174

Full Member
Joined
May 8, 2007
Messages
210
the purpose was to divert hot gasses through the center of the manifold at start up and when exhaust temp rises the butterfly would open up. quicker and higher engine temp helps emissions
 

Ovalis

Sr. Member
Joined
Jan 19, 2011
Messages
405
Loc.
Los Angeles
That version was used for 73-74. 75-77 version was vacuum operated hence the addition of the second PVS on the heater elbow outlet. For 77, the PVS was moved to the back of the intake manifold and obviously that manifold allowed coolant to flow at the back of the manifold.
 

Slowleak

Bronco Guru
Joined
Sep 12, 2013
Messages
4,012
Loc.
Georgia
My ‘77 does not have one and there is nothing I can find in the Ford manual about it.
 
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