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2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
You want to use a rotary vane style pump. Hella makes a good one and they should come with a vacuum shutoff switch and some one way valves. I have mine plumbed in when i was using a high lift. high duration cam. It would build vacuum as I was cruising but not much at all at start up and idle, which is where you need it when you are leaving a restaurant at night....so get some decent one way vaves and plan your systemout ahead of time so you dont get lost in all the hoses. I have 5 or 6 one way valves in my system to insure I dont loose any vacuum if the engine stalls or a line or valve splits. The Rotary vane pumps are more quiet than the diaphram style and last longer. I think I found mine at Summit....I think this is it, max 15hg https://www.summitracing.com/parts/hla-009428081
But you need an auto off switch for 15 inches hg as well
Have you done a reliability analysis for failure points in an electrical headlamp system? There are likely as many risk points in the electric motor, alone, as there are in the entire vacuum system. Then you have wiring (much more failure risk than vacuum hose), power source, ground connections, yada, yada, yada.
You are not going to win this 'contest' on 'system reliability'. Vacuum is easier, lest costly, more reliable, and easier to maintain and troubleshoot. Next!!
Yep- over 600 sets and have personally run mine for 8 hours straight.
Last edited by Richard454; Jul 21, 2021 at 07:36 PM.
Yep- over 600 sets and have personally run mine for 8 hours straight.
if I’m understanding the electric set up correctly, I think I’d rather trouble shoot that wiring if ever than chasing vacuum leaks.
Thanks again all for the info. I will start troubleshooting the vacuum system this weekend and go from there. Anybody have their headlights connected to ported vacuum. My headlights don’t work on that connection but they do if hook up to manifold vacuum from the carb.
Didnt GM go from electric flip ups to vac and then back to electric again?... pretty sure I had electric flip ups on my 84 (which I had constant issues with on the drivers side light not working without popping the hood and spinning a **** by hand to manually start the process to get the motor to work). That said after rebuilding some of the seals on me 74s lights when I got it I havent had any issues in the 8 years since.
Last edited by augiedoggy; Jul 23, 2021 at 08:00 AM.
if I’m understanding the electric set up correctly, I think I’d rather trouble shoot that wiring if ever than chasing vacuum leaks.
Thanks again all for the info. I will start troubleshooting the vacuum system this weekend and go from there. Anybody have their headlights connected to ported vacuum. My headlights don’t work on that connection but they do if hook up to manifold vacuum from the carb.
Its not the wiring you will typically be troubleshooting though...Typically, its gear box/motor assemblies with weak nylon gears
Last edited by augiedoggy; Jul 23, 2021 at 07:59 AM.
So I’m testing components I have found that my res tank does not hold any vacuum. Would this alone make it so the head lights don’t come down? Currently they are staying open. I can close them by attaching the mighty vac to each head light actuator. They stay down for a while but after driving fir a few minutes they pop back up.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Yes, a leak anywhere is going to affect how they operate. Both systems get vacuum from a manifold vacuum port, then it tee'd and one goes to the resevoir and the other to the operating system so if one sid eleaks they are both affected. Especially a big leak like your describing.
Yes, a leak anywhere is going to affect how they operate. Both systems get vacuum from a manifold vacuum port, then it tee'd and one goes to the resevoir and the other to the operating system so if one sid eleaks they are both affected. Especially a big leak like your describing.
Thanks. Taking that tank out does not sound like anything I’m interested in doing. When I change it to full manifold vac port they actually work. But I have to plug into timed vacuum port because I’m using the fulls for booster and dizzy.
When I change it to full manifold vac port they actually work.
The vacuum hose diagram from Willcox shows the vacuum supply connected directly to the manifold outlet behind the carb. Without the res tank you do not a reserve vac supply and are relying on your engine to raise the headlights. 1970 Corvette Vacuum Hose Routing
I have to plug into timed vacuum port because I’m using the fulls for booster and dizzy.
You could try putting a 'T' connector into that booster/dizzy line and see if you can get your headlights to work. Then check to see if it messes with your timing when you raise the headlights.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
You need to get the vacuum tank leak fixed when you can. Until then try and put a T into the manifold line. When you shut down the car or start it you may get some winking as the vacuum builds
You need to get the vacuum tank leak fixed when you can. Until then try and put a T into the manifold line. When you shut down the car or start it you may get some winking as the vacuum builds
The more I troubleshoot this system the more I think I will go to electric head lamps. My car no longer has the wiper cowl so the only need for the entire system is to move lights up or down. I actually think I have several things that need replace or repair. If I go to electric head lamps. All problems are solved. May e I’ll ask Santa……
