1973 454 Manual Transmission Spark Advance Solenoid

[John M.]

What's the skinny with the hard to find 1973 454 Spark Advance Solenoid 1997411? Is there a substitute for a 4 speed car?

[Joe L.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

What's the skinny with the hard to find 1973 454 Spark Advance Solenoid 1997411? Is there a substitute for a 4 speed car?

John------


There's no substitute I know of. The GM #1997411 was discontinued without supercession in February, 1989. 26 years provides a long time for the supply of these to dry up. This part was of extremely limited application----1973-74 Corvettes and Chevelles with big block. That does not bode well for a lot of aftermarket interest in coming up with a replacement.

[John M.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

So what to do? Can you run a 1972 454 solenoid for functionality?

[Joe L.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

So what to do? Can you run a 1972 454 solenoid for functionality?

John-------



That I cannot say. For 1972 only 350 cid engines apparently used the spark control solenoid. I do not know if that one would work for 73-74. It was GM #1114451.

[John M.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Joe,

Any clue of the functional difference between a 1997411 and a 1997413 solenoid. I know the 413 was used for automatics, but what is actual functional difference in operation of the solenoid?

[Joe L.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Joe,

Any clue of the functional difference between a 1997411 and a 1997413 solenoid. I know the 413 was used for automatics, but what is actual functional difference in operation of the solenoid?

John-------


I'm afraid I don't have an answer for that.

[Russ S.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

I too have wondered the functionality difference between a four speed and an automatic TSC.

[Monte M.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

John,
I have a 72, LS-5 car. Is the electrical connection the same. I tried to find a clear picture of the one you need, but all the pictures I ran across did not show that end very clear.
If it is the regular two connections, my guess it would be the same. There are plenty of books that show the guts of them. I am sure I have one of those books if you needed me to look it up.

I understand you want the correct one, if you can find it. But would you really consider hooking it up so it worked correctly. They basically just shut off the vacuum advance unless the car is cold or in forth gear, if it is the same as my 72.

Mine looks correct, but does not work. My car runs MUCH better without it working. The idea was to prevent the vacuum from advancing during any real acceleration unless you were in fourth gear. No advance meat a lot less performance which equaled less emissions.

They look pretty similar. At a glance, I dought one could tell the difference between the two.

Best of luck,
Monte

[Russ S.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Monte, The wire connectors are the same for 72 as 73.

John,
I have a 72, LS-5 car. Is the electrical connection the same. I tried to find a clear picture of the one you need, but all the pictures I ran across did not show that end very clear.
If it is the regular two connections, my guess it would be the same. There are plenty of books that show the guts of them. I am sure I have one of those books if you needed me to look it up.

I understand you want the correct one, if you can find it. But would you really consider hooking it up so it worked correctly. They basically just shut off the vacuum advance unless the car is cold or in forth gear, if it is the same as my 72.

Mine looks correct, but does not work. My car runs MUCH better without it working. The idea was to prevent the vacuum from advancing during any real acceleration unless you were in fourth gear. No advance meat a lot less performance which equaled less emissions.

They look pretty similar. At a glance, I dought one could tell the difference between the two.

Best of luck,
Monte

[Joe L.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

John,
I have a 72, LS-5 car. Is the electrical connection the same. I tried to find a clear picture of the one you need, but all the pictures I ran across did not show that end very clear.
If it is the regular two connections, my guess it would be the same. There are plenty of books that show the guts of them. I am sure I have one of those books if you needed me to look it up.

I understand you want the correct one, if you can find it. But would you really consider hooking it up so it worked correctly. They basically just shut off the vacuum advance unless the car is cold or in forth gear, if it is the same as my 72.

Mine looks correct, but does not work. My car runs MUCH better without it working. The idea was to prevent the vacuum from advancing during any real acceleration unless you were in fourth gear. No advance meat a lot less performance which equaled less emissions.

They look pretty similar. At a glance, I dought one could tell the difference between the two.

Best of luck,
Monte

Monte-------


Yes. The spark advance solenoid was part of the emissions control system. These early systems were sort of a "stop-gap", "band-aid" system pressed into use by the automakers to meet federal and California emissions requirements in the pre-catalytic converter period . As such, they were not well integrated into the overall drivetrain operating systems and resulted in driveability problems as well as fuel economy degradation. Their lack of integration into the drivetrain did have one beneficial aspect, though------it made it relatively easy to disable them and improve driveability and fuel economy. And, that's just what a lot of people did.

The only real reason to maintain these systems as-installed is for originality purposes and/or to pass PV.

[John M.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Does anyone have a picture of a 1997411 or a 1997413 solenoid installed on their 73/74 BB car? Its pretty clear on how the TCS system functions, but I'm trying to understand the differences in the solenoids. Depending on year, some solenoids have 3 ports and some have 2 ports with a vent near the electrical connector. It looks like 1970 is the last time Chevy listed one solenoid for both transmission types. After that there is a different solenoid for each of the transmission types which leads one to believe there is a functional difference...why else would Chevy do this? It would be fun to clear up some of the ambiguity with this topic!

[Harmon C.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

The difference I have noticed is the bracket. I have fixed a broken plastic tube by using any inside parts as a unit from another solenoid . Also on the back side of the bracket their is another part number some times so one bracket was used for two part numbers.

[Joe L.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Does anyone have a picture of a 1997411 or a 1997413 solenoid installed on their 73/74 BB car? Its pretty clear on how the TCS system functions, but I'm trying to understand the differences in the solenoids. Depending on year, some solenoids have 3 ports and some have 2 ports with a vent near the electrical connector. It looks like 1970 is the last time Chevy listed one solenoid for both transmission types. After that there is a different solenoid for each of the transmission types which leads one to believe there is a functional difference...why else would Chevy do this? It would be fun to clear up some of the ambiguity with this topic!

John-------


There is absolutely no doubt there was some difference in the solenoids and it was not solely a "cosmetic" difference.

[John M.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

Guys,

I figured out the difference in solenoids with the help of Doc Rebuilds vacuum advance hose replacement kit diagrams. The answer is simple...its the vacuum ports based on the type of carburetor. We all know a 4 speed car uses a different carburetor than an automatic car. In the case of a 1973 BB 4speed car its a Rochester 7043201 carb vs automatic car Rochester 7043200 carb.

The 4speed vacuum advance solenoid has 2 vacuum ports in the front of the solenoid and vent in the rear of the solenoid by the electrical connector. The automatic vacuum advance solenoid has 2 vacuum ports in the front of the solenoid and a vacuum port in the rear of the solenoid by the electrical connector. Both solenoids mount in the same place on the intake manifold, hence they share the identical mount bracket.

Both solenoids accomplish the same function in the TCS system. Attached is a pic of the vacuum hose diagrams from the Doc to show the difference.

Solenoids.jpg

[Peter G.]

Re: 1973 454 Manual Transmission Spark Advance Solenoid

The hose routing is different on the Automatics vs. the Manuals.