I am rebuilding my 4 speed saginaw. On the tranmission side cover assembly, there is some sort of electrical sending unit with a spring loaded ball bearing bolted into the side shaft of the reverse shaft, and another one bolted in below the 3rd/4th shaft?? I need new ones, but don't know what they are called? My only guess would be, one is neutral safety, and one is for reverse back-up lights?? Need your help yet again Jay
Tcs switch which controls ignition advance and is activated by the gear postion depressing or not depressing the ball bearing which either makes or breaks a switch.
the one on the 3/4 shift shaft is the tcs switch,and the one on the reverse shaft is the rev. light switch. the neutral safty switch is on the column.
Okay, now I'm getting somewhere, would a 71 skylark 350 that I am going to convert to 4 speed use the tcs switch, and if is there wiring down there for it? Where do I get the reverse wiring, since I currently have column shift auto. Jay What would I ask for in the parts store?
Let me rephrase that, I am running points with petronix. Were the skylarks originally wired for this switch? Can I just plug it and not affect the drivability?
I assume that you mean you are using an electronic pic up in lieu of points. It is part of a stock wiring harness for the year, original engine , trans and so forth. So if yours came equipped with a 4 speed it would have the female plugs for the male spades on the switches that scerw into the trans. Or you can buy that harness from M&H www.wiringharness.com
Yes, thanks I am running an electronic pick-up, by my Skylark came from the factory with a TH350 automatic. So I'm thinking that my Lark was not wired for this switch.
tcs stands for transmission controlled spark. what it did was regulate the amount of vacuum advance in 3rd and 4th gears and in 3rd gear with a automatic. has nothing to do with the internals of the dist. yours should have a solenoid mounted on the carb like in the pic. it was the there way of controlling hydra carbon output while at cruise . if you dont have the soleniod youll have to get one too. the tcs switch is internal on the automatics and its mounted on the valve body. you can use your orignal harness with some cutting and splicing down at the tranny. but i assume its the orignal 30 year old engine harness. i would replace the harness with a new one. you can contact m&h and tell them what you are doing and if they dont make a 350 4 speed harness they can do some custom changes to the auto harness for you so it still looks oe. but if you dont want to hook it up it wont hinder perfomance if its not hooked up. just have to run your vacuum advance to ported or manifold vacumm depending on what your engine likes.
Nice, Thanks for the responses!!! I do not have this switch anywhere near the carb or anywhere. Although, who knows who could have eliminated this over the years. I run my vac. advance of manifold vacuum and seems fine. Where can I find this particuler back-up switch that loks the same, screwed into the cover with the little called bearing that is spring loaded?
