How to "unlock" 700R4 convertor without "ported" vacuum??

[cwmusser]

I need some 700R4 knowledge here. I just discovered my carburetor does not have a "ported" vacuum port. My Painless #60109 lock-up kit (installed in my new transmission), requires it or my converter will stay locked up. I'm also running an Edelbrock Eforce supercharger with just 5-6 lbs. boost but I'm also being told that because of the SC I may not see low enough vacuum to release it anyway. Not sure about that.
I'm sure I'm not the first to have this problem so if anyone knows of a solution that works well I would appreciate knowing about it.
Thank you!!

[dontlifttoshift]

Theres three terminals on that switch so it can be normally open or normally closed. If Painless is calling for ported vacuum you could easily hook it to manifold vacuum and wire it opposite of what they are telling you and it would function just fine.

That said, the instructions that I found online for that part number say to connect the switch to manifold vacuum, but it does show a different switch.. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://static.speedwaymotors.com/pdf/910-64038.pdf

Look closely in the vacuum port and see if the is an allen screw in there. Most of those switches are adjustable, if yours isn't one can be purchased.

[cwmusser]

Donny, thank you for your response to my question. The Painless instructions say to connect both the transmission and the brake switch to "common" or "normally open" (which one goes where doesn't matter). If I understand you correctly, you're saying I can connect to common and normally closed and run the vacuum line to manifold vacuum. Is this correct? It's obvious you know a lot more about this than I do, but just wondering how that will cause the converter to unlock at idle, which I understand is what the "ported" vacuum will do when "normally open". Also, yes, my vacuum switch does have an adjustment screw. Thank you again!

[dontlifttoshift]

All of this is only functional when in 4th gear, as it is wired through the 4th gear pressure port. Right? It will also unlock with the brake switch.

As soon as the trans downshifts out of 4th, the converter will unlock regardless of the vacuum switch. The whole point of the vacuum switch is to unlock the converter when engine load goes up, say part throttle cruise and you come up on an incline and need to tip into the throttle a bit.

Manifold vacuum will be highest at closed throttle and lowest at wide open throttle. Ported vacuum will be opposite of that. If you are going to connect to manifold vacuum, you want to wire it so the switch is closed in high vacuum and open in low vacuum. In this case, based on what you said above, you would connect to common and normally open and then adjust the switch until it locks unlocks as you see fit.

[cwmusser]

Thanks Donny, that explanation makes it much easier to understand. Since my last message I was able to talk to the person who built my trans on SoCal. He basically told me to just hook it to manifold vacuum and run it, adjust from there. I will try it as instructed, see how it goes and then switch the wires and try it that way as well. I also received a message from Bowler Trans. that their kit has a timer and does not use vacuum if all else fails. Looks like I have plenty of options that I didn't realize. I really appreciate your input on this. Thanks again!!

[dontlifttoshift]

Yeah, I quit using the vacuum switches a long time ago and use the Bowler setup for lock up on all of the analog transmissions. With the timer you don't get unlock when tipping in to the throttle but you don't have to deal with unwanted lock/unlock cycles. It also keeps the converter lock from stacking on top of the 3/4 shift and really lugging the motor down which is especially a problem with a looser converter.