VSS activated switch

vette427sbc

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I'm in the middle of a t56 swap in my dads tri-five chevy and the reverse lockout wiring is next on the list of things to do.
I was thinking about wiring the solenoid to the brake light switch, but I think that cycling the solenoid every time you hit the brakes would cause it to wear prematurely. So my next idea would be a VSS actuated switch. The car has a regular old carburated sbc, so theres no computer to run the switch off of.
Have any of you heard of a switch that will activate at a certain # of pulses? Or maybe just other ideas on how to activate this solenoid?
 
I'm in the middle of a t56 swap in my dads tri-five chevy and the reverse lockout wiring is next on the list of things to do.
I was thinking about wiring the solenoid to the brake light switch, but I think that cycling the solenoid every time you hit the brakes would cause it to wear prematurely. So my next idea would be a VSS actuated switch. The car has a regular old carburated sbc, so theres no computer to run the switch off of.
Have any of you heard of a switch that will activate at a certain # of pulses? Or maybe just other ideas on how to activate this solenoid?

Keep it simple. Wire the output of the brake light switch in series with a clutch switch. The solenoid would only energise when you have the brake on and the clutch depressed. Most likely, you only have this situation when stopped. (Kinda necessary when going into reverse).:beer:
 
The reverse lockout has a stout spring on it to prevent accidental engagement. You can "crash" through the spring gate and get into reverse fine. I tried different things and just added complication. If you are extra cool you could put a button on the shift handle or knob that actuates the solenoid.
 
The reverse lockout has a stout spring on it to prevent accidental engagement. You can "crash" through the spring gate and get into reverse fine. I tried different things and just added complication. If you are extra cool you could put a button on the shift handle or knob that actuates the solenoid.

I was told by american powertrain that forcing through the spring can mess up the transmission.
 
Keep it simple. Wire the output of the brake light switch in series with a clutch switch. The solenoid would only energise when you have the brake on and the clutch depressed. Most likely, you only have this situation when stopped. (Kinda necessary when going into reverse).:beer:

I like this idea. Simple switch logic.

I wouldn't worry about killing the solenoid with use. What usually kills solenoids is being held "on" too long.
 
I wouldn't worry about killing the solenoid with use. What usually kills solenoids is being held "on" too long.

I'll add my 2 cents here.
Solenoids are like linear motors. The draw approximately 6 times normal current levels when first energised. This is called "locked rotor." Just as a motor speeds up and the starting current lowers and levels off, a solenoid will drop down it's draw once it has moved to it's intended "new" location. (Pulled in).
IF a solenoid is mechanically prevented from "throwing" all the way, the elevated current will kill them.
ALSO, when first energised, and when de-energised, it WILL throw a "spike." This is why all coil loads on an 81 with ECM have little diode bridges across the coils to suppress this spike, and help prevent the ECM from being zapped.
 
I wouldn't worry about killing the solenoid with use. What usually kills solenoids is being held "on" too long.

I'll add my 2 cents here.
Solenoids are like linear motors. The draw approximately 6 times normal current levels when first energised. This is called "locked rotor." Just as a motor speeds up and the starting current lowers and levels off, a solenoid will drop down it's draw once it has moved to it's intended "new" location. (Pulled in).
IF a solenoid is mechanically prevented from "throwing" all the way, the elevated current will kill them.
ALSO, when first energised, and when de-energised, it WILL throw a "spike." This is why all coil loads on an 81 with ECM have little diode bridges across the coils to suppress this spike, and help prevent the ECM from being zapped.

Yup see that on all sorts of coils in a GM schematic....I stuck one across the coil on the a/c clutch, since it's controlled with the computer a/c input signal...:shocking:
 
Off topic - damn Z-Man that car in your sig has the best paint I have seen in a long time on a fiberglass car. The photo is also interesting how the background is bought up in the color of the car. Back to your regular scheduled program.

Just push it and avoid all the crap. I tried a bunch of stuff and that has been the easiest and lowest maintenance.
 
vss switch

If any one is interested you can use this chip in a simple circuit to turn a switch on or off at a specific speed.

http://www.national.com/mpf/LM/LM2917.html

i used this circuit to stop a 700r4 from locking up the converter when the car was under a certain speed it worked great.

You could use a speed sensor out of a early 80's cruise control system if you car does not have a speed sensor

i hope this helps

Terry
 
If any one is interested you can use this chip in a simple circuit to turn a switch on or off at a specific speed.

http://www.national.com/mpf/LM/LM2917.html

i used this circuit to stop a 700r4 from locking up the converter when the car was under a certain speed it worked great.

You could use a speed sensor out of a early 80's cruise control system if you car does not have a speed sensor

i hope this helps

Terry

I used to have many of those OLDE TYME design manuals but tossed them, looking at that brought back memories....thanks....

and yes, I would like to spend some time maybe picking up a couple cheeeeep China import large RED LED clocks, and using the displays with a home built driver like that...for tach and speedo in my '72.....

:shocking::search::yahoo:
 
I'm in the middle of a t56 swap in my dads tri-five chevy and the reverse lockout wiring is next on the list of things to do.
I was thinking about wiring the solenoid to the brake light switch, but I think that cycling the solenoid every time you hit the brakes would cause it to wear prematurely. So my next idea would be a VSS actuated switch. The car has a regular old carburated sbc, so theres no computer to run the switch off of.
Have any of you heard of a switch that will activate at a certain # of pulses? Or maybe just other ideas on how to activate this solenoid?
Yep!
http://www.rx4speeding.com/Speed_Activated_Switch_SAS_12V_SAS_24V.html
I think I am going to get one for me. But, I'm going to get it so I can disable my electric radiator cooling fans above 40mph since they are not needed above that speed.

I also have a T56 Magnum in my '55 Bel Air and have been thinking about the issue you describe with it too. However, I don't think this speed switch is the best solution for that use.

Here's what I am doing. I don't have it hooked up yet though.
I ordered this timer:
http://www.wolstentech.com/products/timedelayrelay/timedelayrelay.php
I will activate it with a momentary switch that I'll mount on the bottom side of the dash.
 
I'm in the middle of a t56 swap in my dads tri-five chevy and the reverse lockout wiring is next on the list of things to do.
I was thinking about wiring the solenoid to the brake light switch, but I think that cycling the solenoid every time you hit the brakes would cause it to wear prematurely. So my next idea would be a VSS actuated switch. The car has a regular old carburated sbc, so theres no computer to run the switch off of.
Have any of you heard of a switch that will activate at a certain # of pulses? Or maybe just other ideas on how to activate this solenoid?
Yep!
http://www.rx4speeding.com/Speed_Activated_Switch_SAS_12V_SAS_24V.html
I think I am going to get one for me. But, I'm going to get it so I can disable my electric radiator cooling fans above 40mph since they are not needed above that speed.

I also have a T56 Magnum in my '55 Bel Air and have been thinking about the issue you describe with it too. However, I don't think this speed switch is the best solution for that use.

Here's what I am doing. I don't have it hooked up yet though.
I ordered this timer:
http://www.wolstentech.com/products/timedelayrelay/timedelayrelay.php
I will activate it with a momentary switch that I'll mount on the bottom side of the dash.

Welcome to the motley crew ......

I C post #1 there.....

I have to say that adding any switch to the electric fans is redundant in that the fans draw no current above 40 mph anyway, inrushing air in fact spins the blades turning the motors into generators....

:smash:
 
Welcome to the motley crew ......
I C post #1 there.....
I have to say that adding any switch to the electric fans is redundant in that the fans draw no current above 40 mph anyway, inrushing air in fact spins the blades turning the motors into generators....
:smash:
Thanks for the welcome.
I do have to disagree with you on your comment though.
Incoming air will not spin the blades to anywhere near the speed of the fans when they are powered. The current draw will be virtually the same even traveling at highway speeds if the fans are powered (this would be easy to test with an ammeter). The ECUs used in newer cars use the VSS signal as one of the parameters in controlling fans. So, the factory does it and for good reason.

A better argument would be that at highway speeds, the fans would be turned off anyway from the other sensors. And that may be true most of the time except for very high ambient temperatures or an unusually high engine load.
I am using a Dakota Digital controller and a 2 speed fan wiring design that GM also uses. I also am using an A/C high pressure signal to the controller that can turn the fans on from that too. Again, a newer car's ECU uses all these parameters too but still uses VSS data to shut fans off if necessary.
 
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We ended up just wiring the lockout into the brake pedal. You just have to be careful if you are on the brakes going from 6th to 5th.
Got any pics of your '55? My fathers is a '55 hardtop... actually a 210, but its got a few of the belair trim pieces. The T56 works beautifully in his car.
 
We ended up just wiring the lockout into the brake pedal. You just have to be careful if you are on the brakes going from 6th to 5th.
Got any pics of your '55? My fathers is a '55 hardtop... actually a 210, but its got a few of the belair trim pieces. The T56 works beautifully in his car.
Yes, I've got a zillion pics and the links to them are in my signature. I'm in the middle of a restomod on it and have at least another year to go on it.

Here's about where I am on it now except I've prepped and primered the fenders and doors and am fitting them on the car as we speak.
http://www.hotrodders.com/gallery/data/3537/medium/Hood1.jpg

Here's a couple of pics from along the way. I got the car in September of '09. I retired in August of '08 and got my workshop built the first year.

Frame_off1.jpg


And the Vette:


Frame_Blasting_3Q_Complete1.jpg


Epoxied_Frame.jpg


Engine.jpg


IMG_7007.JPG


IMG_7350.JPG


IMG_6739.JPG


Oops. Gotta repaint that cold air intake tube!
Engine_with_Circulating_heater_valve.jpg


Oh, and here's my workshop:
Shop_New_Letters3.jpg


And, the Vette:
VetteShop.jpg
 
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Welcome to the motley crew ......
I C post #1 there.....
I have to say that adding any switch to the electric fans is redundant in that the fans draw no current above 40 mph anyway, inrushing air in fact spins the blades turning the motors into generators....
:smash:
Thanks for the welcome.
I do have to disagree with you on your comment though.
Incoming air will not spin the blades to anywhere near the speed of the fans when they are powered. The current draw will be virtually the same even traveling at highway speeds if the fans are powered (this would be easy to test with an ammeter). The ECUs used in newer cars use the VSS signal as one of the parameters in controlling fans. So, the factory does it and for good reason.

A better argument would be that at highway speeds, the fans would be turned off anyway from the other sensors. And that may be true most of the time except for very high ambient temperatures or an unusually high engine load.
I am using a Dakota Digital controller and a 2 speed fan wiring design that GM also uses. I also am using an A/C high pressure signal to the controller that can turn the fans on from that too. Again, a newer car's ECU uses all these parameters too but still uses VSS data to shut fans off if necessary.

HUmm, interesting, I have to do some checks on that, plug my DVM into the leads and see, got my curiosity up....I have heard many times the fans draw almost no current at speed, which makes sense to me...but...well...never did a test, ...

:huh:
 
HUmm, interesting, I have to do some checks on that, plug my DVM into the leads and see, got my curiosity up....I have heard many times the fans draw almost no current at speed, which makes sense to me...but...well...never did a test, ...
:huh:
Yes, it would be interesting. I've been thinking about it a little more since I posted my opinion too. It's been a long time since I took physics. Does a brush type of DC motor use more current under a heavy load versus a lighter one? My first reaction is that it is the same but now I'm not sure. Maybe it will use less with help to push the blade. I still believe the fans would turn much slower by the windmill action versus being switched on. We've got some 80 mph speed limits here in Texas on I10. Maybe they would turn fairly fast at that speed. I'll be interested in your results if you do a test.
Wouldn't this little gizmo be good to have for that?
http://www.powerwerx.com/tools-meters/watts-up-meter-dc-inline.html

Edit:
A little more thought towards the load/no load thing. The brushes of a permanent magnet dc motor will be in contact with the stator windings for the same amount of time at any rpm or load. And the resistance in the stator remains constant. Therefore the current draw will be the same. Any EEs out there? Am I not considering something?
 
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