Please identify vacuum valves (1 Viewer)

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midwest (iowa)
My PO gave me a bucket of valves after his failed attempt at a Desmog. I am in the final stages of putting this back together, completely rebuilt engine, Jim c. carb and dizzy. I have no idea what these valves are called. . As a matter of fact, any valves not pictured are probably still in the bucket. I would appreciate identifying those as well. Pretty much every valve is loose and unidentified.

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two on the top right that say VCV are vacuum control valves for the EVAP system, The brown one is an EGR vacuum modulator, The bottom right is a HAC or high altitude compensator valve. The other 2 with the green and blue are vtv...vacuum transmitting valves One I believe goes to the choke breaker and the other probably by the bvsv
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I am forever Grateful that I don’t have to deal with emission stuff down where I live anymore. Liven free!
 
You need a copy of the emissions manual. See attached.

One of the VCVs clips under the air cleaner housing on the passenger side to control ventilation of the distributor. The emissions manual doesn’t have a good drawing showing how it’s supposed to be hooked up.
 

Attachments

  • 2F Emissions Manual.pdf
    2.7 MB · Views: 65
This image from the emissions manual show much of how things get hooked up. The items 1-12 in the lower right correspond to the vacuum hoses as they come off the metal piping. the pic of the numbered dots is a visual of what that piping looks like with the hoses off and how they are numbered. The image in the upper right corner is the passenger side of the carb and how those 4 vacuum lines connect. But OSS is right there is no image of the VCV below the air cleaner on the dizzy side.

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My PO gave me a bucket of valves after his failed attempt at a Desmog. I am in the final stages of putting this back together, completely rebuilt engine, Jim c. carb and dizzy. I have no idea what these valves are called. . As a matter of fact, any valves not pictured are probably still in the bucket. I would appreciate identifying those as well. Pretty much every valve is loose and unidentified.

View attachment 2936053
@g-man nailed it. The blue-ended VTV is used in the Air Injection system and it sits between the power steering pump and the valve cover. One end connects to a stub from the big mess of hard vac lines, and the other end goes to the lower BVSV (one of the things with two vac ports that threads into the driver's side of the thermostat housing). See photo below for location and orientation of the blue end. The orientation DOES matter on the VSVs, including your green one at the choke breaker vac line.

Blue VTV.jpg


I also have a blue one as part of the Spark Control system. It goes in line before the main (not HAC) hose to the dizzy advance diaphragm (the larger one). This is a feed from ported vacuum on the carb. See the emissions manual photo below. The manual states this is a brown one, but I've always had a blue one in place and never noticed the discrepancy. Can anybody tell me how this will affect timing? Obviously blue, brown, and green have different flow rates. I don't have knock under load, but I run pretty darn lean on my A/F gauge at 70-95% throttle. Like 16-17:1. Carb is a Jim C rebuild from 10/2020 and trust me I know my smog system inside and out - it's fully working.

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Found the info on VTVs, see photo below. So blue is flowing less air, meaning vacuum isn't pulling on my main advancer diaphragm as much, meaning not as much advance at rpm?

VTV info.jpg
 
^^^ I don't think it will pull less on the diaphragm, but rather less vacuum causes a DELAY in the time that it takes to move the diaphragm. Look at this test:

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and in this one...bottom right says "delayed by the VTV".
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^^^ I don't think it will pull less on the diaphragm, but rather less vacuum causes a DELAY in the time that it takes to move the diaphragm. Look at this test:

View attachment 2936290

and in this one...bottom right says "delayed by the VTV".
View attachment 2936295
This is good stuff man. I wonder though, if delay just means the particular "lever" (used generically, like whatever the vacuum is acting on) the vacuum is pulling is delayed until vacuum reaches a threshold, and the VTVs are slowing down the buildup of vacuum at the lever, so it reaches threshold more slowly. And I wonder what the threshold of the start movement is on the advancer diaphragm. Obviously that diaphragm will move more with more vacuum, so there's a curve there. But having the incorrect flow of vac to the advancer could affect the onset of the curve and the curve itself. Of course all of that is going to affect spark timing advance.

Partsouq lists the blue for my 83, but the 1981 Emissions manual (the same one everybody's got a digital copy of it) states brown. I'm picking up the blue 82 60 later today so it will be interesting to see what that has in it. Seems like it changed sometime between 81 and 83.
 
VTVs are just restrictions to air flow one way and free flow the other.
Air flows slower (so vacuum actuator opens slower) when flowing through a VTV pin-hole than no hole.
The different colors designate the air flow the valve will pass. Some faster than others.
 

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