1974 TCS Configuration
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Vice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.- Top
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Re: 1974 TCS Configuration
For 1970 applications the port on the end with the electrical connections connects via a hose to the carburetor air inlet horn. For 1971 and 1972 that same port has a cube of foam over it, as Patrick mentions. That port is a vent for the vacuum line to the distributor actuator -- it is not only necessary to stop the vacuum to the actuator, but to vent the actuator to the atmosphere so that it returns to the "rest" or natural position.Terry- Top
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Re: 1974 TCS Configuration
In the picture of the torn apart solenoid the third port is out of the housing and in the lower right of the picture.Lyle
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Re: 1974 TCS Configuration
I see it now Lyle. So does that mean that even 1974 had the third port? If true that would make me think that perhaps all of the TCS solenoids had three ports.Terry- Top
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Re: 1974 TCS Configuration
I think all TCS solenoids had three ports. The only difference I have seen in any of them was the bracket. At one time I bought some NOS solenoids that had an odd bracket for $1.00. I used all the new parts and my original bracket and they work as they should.Lyle
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Re: 1974 TCS Configuration
Every one of these I've ever seen uses that third port as a vent, as others have mentioned. The vent had a small foam filter, but these seldom lasted too many years. On a 72 I once had, I cemented an old paper fuel filter to the hose. I still have that laying around some place because I liked to use the solenoid with manual switch control to get past the smog Police rather than have the control system determine when I can have full time Vacuum advance. You might want to consider that as an option.
Stu Fox- Top
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Re: 1974 TCS Configuration
Far more likely is that they look in "some book" that has it all incorrect and you have to spend your time convincing them of how it's really supposed to be configured.
PatrickVice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.- Top
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Re: 1974 TCS Configuration
Every one of these I've ever seen uses that third port as a vent, as others have mentioned. The vent had a small foam filter, but these seldom lasted too many years. On a 72 I once had, I cemented an old paper fuel filter to the hose. I still have that laying around some place because I liked to use the solenoid with manual switch control to get past the smog Police rather than have the control system determine when I can have full time Vacuum advance. You might want to consider that as an option.
Stu Fox
What do you mean by "manual switch control"?- Top
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Re: 1974 TCS Configuration
The solenoid is picked up by a 12v signal applied to it from the emission control system, i.e. typically something like 7 seconds after your tranny goes into high gear for cruising. Therefore you provide it with a manually switched 12v source (hidden of course) so you can control when it is picked up to give you vacuum advance. The vacuum source (port) in the carb may then be opened up if you want full time manifold vacuum. In the QJ, that port connects to a chamber at the butterfly with it's port slightly above the butterfly. A simple drill or file procedure can be used to open the port into the chamber so it is at or below the butterfly position at idle.
Stu Fox- Top
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Re: 1974 TCS Configuration
I think all TCS solenoids had three ports. The only difference I have seen in any of them was the bracket. At one time I bought some NOS solenoids that had an odd bracket for $1.00. I used all the new parts and my original bracket and they work as they should.
My original belief about all the solenoids being the same has been reinforced by your statements. I'll just ignore the two-port v three port nonsense.Terry- Top
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Re: 1974 TCS Configuration
Terry,
It might seem 'nonsense' to you, but not all of us have the years of exposure you have had and are still learning. I know I'm very much still in the latter category.
Here are some photos of a NOS 1997410 solenoid which is common to '73 and '74 L48 4 speed cars, and possibly other applications. This is the peice that I have referred to as a two port solenoid, for obvious reasons. It is hardly obvious by casual observation that this is actually a three port solenoid especially when clues offered by other members mention that the third port would have a rubber tube and foam filter attached. It is also markedly different than Paul's solenoid, and more than by simple placement of the mounting bracket. The vent (or third port) becomes partially visible in the third picture and can really only be seen in the fourth picture when backlit through the screen/filter.
It could be that this particular solenoid is a service replacement part and different in configuration than assembly line pieces. If so, then this knowledge might be useful to other restorers or on the judging field.- Top
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Re: 1974 TCS Configuration
Terry,
It might seem 'nonsense' to you, but not all of us have the years of exposure you have had and are still learning. I know I'm very much still in the latter category.
Here are some photos of a NOS 1997410 solenoid which is common to '73 and '74 L48 4 speed cars, and possibly other applications. This is the peice that I have referred to as a two port solenoid, for obvious reasons. It is hardly obvious by casual observation that this is actually a three port solenoid especially when clues offered by other members mention that the third port would have a rubber tube and foam filter attached. It is also markedly different than Paul's solenoid, and more than by simple placement of the mounting bracket. The vent (or third port) becomes partially visible in the third picture and can really only be seen in the fourth picture when backlit through the screen/filter.
It could be that this particular solenoid is a service replacement part and different in configuration than assembly line pieces. If so, then this knowledge might be useful to other restorers or on the judging field.
The 1997410 is obviously different from the 1997425 that I have. And Dr. Rebuild says that that is the difference between the four-speed and the TH400. Yes the ...425 is definitely three-port. It came from that PartsLadi in Florida.- Top
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Re: 1974 TCS Configuration
Terry,
It might seem 'nonsense' to you, but not all of us have the years of exposure you have had and are still learning. I know I'm very much still in the latter category.
Here are some photos of a NOS 1997410 solenoid which is common to '73 and '74 L48 4 speed cars, and possibly other applications. This is the peice that I have referred to as a two port solenoid, for obvious reasons. It is hardly obvious by casual observation that this is actually a three port solenoid especially when clues offered by other members mention that the third port would have a rubber tube and foam filter attached. It is also markedly different than Paul's solenoid, and more than by simple placement of the mounting bracket. The vent (or third port) becomes partially visible in the third picture and can really only be seen in the fourth picture when backlit through the screen/filter.
It could be that this particular solenoid is a service replacement part and different in configuration than assembly line pieces. If so, then this knowledge might be useful to other restorers or on the judging field.Lyle
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Re: 1974 TCS Configuration
Here's another version, note the white connector
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