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Discussion Starter #1
Thanks to everyone who took the time to respond to my original post. I am at the point where i am very happy with both the "mechanical" the car runs very well,as well as the "visual" back to factory original appearance of my 70 SS. The only thing missing from the restoration is the (T.C.S.) Although i realize that the addition of this part is a personal decision, i would be interested in opinions as to wheteher this addition is difficult to set up for proper operation and if it also may hurt performance or driveability. In other words may this turn out to be more trouble than it's worth. Any thoughts from members having experience with this part is appreciated.
 

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If you are doing a correct resto, put it on and hook it up like factory. Period. Otherwise, throw it in the river and use manifold vacuum straight to the dist, and clean up the engine of excess plumbing. Test it for operation with 12v (I use my small bat charger) to the 2 terminals to make sure it "clicks" and suck (or blow) on the ports to be sure the valves open and close when it clicks. Once the engine is heated up and running normally, this system is providing engine vacuum full time to the dist. anyway.

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DZAUTO - I have a complete schematic and service manual that describes the operation of TCS and the manual claims that TCS interrupts dist vacuum in 1st and 2nd gear and only allows full vacuum in high gear under normal operating temp. When cold or too hot a temp override switch kicks in, disables the vacuum solenoid and allows full vacuum to dist.
My opinion is that it will be very hard to find all the parts: Vacuum control solenoid, override relay, temp override switch, trans switch and wire harness. Before you decide you need to look at your tranny and verify that it has the switch - for the turbo 400 you should have two terminals on the drivers side, one for kickdown and the other TCS.
If you do decide to install it you could have your cake and eat it too. Which means, install all the components but wire it up so that you have full vacuum all the time.
The easiest way to defeat the system is to remove or install a blown TCS fuse. This prevents 12V getting to the vacuum control solenoid and allows full vacuum all the time.

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Steve Strasemeier (70SS)
 

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Steve S, there has to be a gazillion people out there who have old, but working, TCS solenoids and haven't thrown them away yet, both BB & SB versions. I'm not sure, but I believe the Temp kickdown relay or switch, is available and the 2 terminal temp sender is available everywhere (I just bought one from NAPA).

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Steve-

I agree with everything but the last part. I also have a diagram of the system and have spent time studying it on my '70. If you 'cheat'the solenoid out of electricity, you are depriving vacuum to the vacuum advance. There MUST be constant power to the solenoid, this is what pulls in the plunger directing the vacuum to the distributor. When normally driving in high gear, the TCS solenoid is live with 12 volts.

If you are going to "outsmart" this system, but keep everything under the hood original, you're going to have to find a way to rig the relay or wiring so that solenoid gets its power.
 

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If you agree with the first part then you have to agree with the last. While it is true that the solenoid has 12V on one side it does not have a ground on the other terminal. It gets the ground from the trans switch and only in 1st and 2nd gear. So the vacuum solenoid is off and you get full vacuum in high gear. Are you sure yours is hooked up right? If the vacuum lines to the solenoid for clean air and manifold vacuum are reversed your system would work as you say.
Could someone else chime in here I hate to give out bad info.

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Steve Strasemeier (70SS)


[This message has been edited by Steve S (edited 02-03-99).]
 

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Steve-

I don't want to make an argument out of this. You've helped me in the past. I just want to clear up what I looked up. I've also pulled and studied each TCS piece on my '70 Malibu.

The solenoid is energized in HIGH GEAR. You are right, the tranny switch is what grounds the solenoid *BUT* it grounds when it is in high gear! The fluid pressure increases in "hi" The transmission fluid exerts force on the switch. The switch grounds, completing the circuit. It completes the negative side of the 12 volt circuit to the solenoid. The other terminal is connected to the Positive (+) of the electrical system (thru the ignition "on" circuit). Thus you have an energized solenoid, a pulled back plunger, and full vacuum advance to the distributor.

I left my equipment off! I just ran the vacuum advance line right to the carb. Makes things simple. If I ever want show quality, it's going back on and it will WORK like factory.
 

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Coppertop thanks for the info. DZAUTO I owe you an apology. Practical experience beats reading an article anytime. The paper I have shows the tranny switch to be open in high gear and the vacuum solenoid plunger allowing full vacuum in the de-energized mode. The description of operation also has it all backwards. This article was in an NCOA issue.
Sorry guys!
One more item I don't understand. Does the temp override switch disable the vacuum solenoid when cold or too hot? If so everthing in this article is backwards

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Steve Strasemeier (70SS)
 
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