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the vacuum reservoir is used to maintain vacuum level. Is it necessary to have one, no but if you want a full working system, yes. You could convert your wipers and headlights to electric however
I am not 100% sure of this, but I believe the need for a vacuum canister is so that you can close the headlight AFTER the engine is shut down. The check valve in the system retains the vacuum after the engine is no longer producing vacuum.....so, you could bypass the canister and as long as the engine is running, you can close and open the lights, as well as the windshield wipers if you have that system.
And I am pretty sure we can ALL survive the crisis of not being able to close the headlights, or operate the windshield wipers AFTER the engine is turned off. Sorta like the crisis of not knowing one of your fancy fiberoptic side marker / tail light indicators have failed on a pre 73 Corvette.
On my 69, I have no intention on installing that huge vacuum canister in the left side area of my engine compartment. In fact,....I have no intention of using the vacuum headlight system at all. Probably not using the vacuum actuated system for raising and lowering the windshield wiper doors. AND,....certainly not even considering running fiberoptic lines to side marker / tail marker lights so I can constantly be informed as to the status of those lights.....!!! For me....its all useless whizbang stuff that has no application in my real world of driving. I care more about functional and simple systems that work when necessary without constant fiddling......especially when you drive the 5000 miles a year I do. I car too much about the experience and joy of driving the car.
The problem also is when the engine is under load vacuum drops, the tank is there to stabilize vacuum. For example If you have no tank and your windshield wipers are on they will work poorly and let's say you floor it or start climbing a grade your wipers will loose vacuum, which means they won't work.
The problem also is when the engine is under load vacuum drops, the tank is there to stabilize vacuum. For example If you have no tank and your windshield wipers are on they will work poorly and let's say you floor it or start climbing a grade your wipers will loose vacuum, which means they won't work.
So.......if you are out driving in the rain, when you floor it......or going up a grade, the wipers may slow down or stop a couple seconds, till you get your foot off the "floored" position or once the car is stabilized on a grade. Is this a situation one commonly find himself in in a C3 Corvette? I guess the OP needs to decide if this is a relevant issue. Its important to make that distinction for your use of the car.
My point, at least for my driving requirements, is that some of these systems are poorly designed in the first place, but more importantly require attention and countless troubleshooting theads on this forum prove that. I simply don't have the desire, or time, to fuss with systems that are almost useless to me. A vacuum operated headlight actuating system is almost irrelevant to me. I think I drove my 77 twice at night since the five years I restored it, yet I put 5000 miles on it every summer since. I have used my windshield wipers ONE TIME, on the way back from Carlisle when I got caught in the rain. The potential downside to ANY vacuum being tapped of an engine, is engine performance issues if these systems leak. Everything has a price and reward.......I see little reward in these systems for the driving I do.
The 77 did away with the James Bond silly windwhield wiper door system,...the wipers simply live behind the longer hood of the 77.......NO PROBLEM, NO VACCUM, NO SWITCHES, NO FUSSING WITH IT. I am going to have that door on the 69, but probably just going to make it a manual system where I get out of the car, open the hood, and push on a lever to put them up......for that once every five years that I even need them to work. . As for my headlights, I drove the 77 first three years after restoration with NO vacuum or electric. It takes 30 seconds to pull over, and push them up manually. When I get home, I push them back down manually. Simple. There is NO situation in which nightime sneeks up on me and I am suddenly driving in the dark. On my 69 convertible........I am doing the same......manual. Not wasting money or time.
Some Corvette owners like all these quirky systems and find joy in making them work......I am not one of them. Got better things to do. While some are working hours in the garage to make this stuff work.....I am out driving the 77, the 69,...or the Harley. Thats what matters to me.
Last edited by Shovels and Vettes; Mar 25, 2023 at 01:02 PM.
So.......if you are out driving in the rain, when you floor it......or going up a grade, the wipers may slow down or stop a couple seconds, till you get your foot off the "floored" position or once the car is stabilized on a grade. Is this a situation one commonly find himself in in a C3 Corvette? I guess the OP needs to decide if this is a relevant issue. Its important make that distinction.
It's an electric motor. Once the door is open it doesn't care about vacuum levels!
So.......if you are out driving in the rain, when you floor it......or going up a grade, the wipers may slow down or stop a couple seconds, till you get your foot off the "floored" position or once the car is stabilized on a grade. Is this a situation one commonly find himself in in a C3 Corvette? I guess the OP needs to decide if this is a relevant issue. Its important make that distinction.
My point, at least for my driving requirements, is that some of these systems are poorly designed in the first place, but more importantly require attention and countless troubleshooting theads on this forum prove that. I simply don't have the desire, or time, to fuss with systems that are almost useless to me. A vacuum operated headlight actuating system is almost irrelevant to me. I think I drove my 77 twice at night since the five years I restored it, yet I put 5000 miles on it every summer since. I have used my windshield wipers ONE TIME, on the way back from Carlisle when I got caught in the rain. The potential downside to ANY vacuum being tapped of an engine, is engine performance issues if these systems leak. Everything has a price and reward.......I see little reward in these systems for the driving I do.
The 77 did away with the James Bond silly windwhield wiper door system,...the wipers simply live behind the longer hood of the 77.......NO PROBLEM, NO VACCUM, NO SWITCHES, NO FUSSING WITH IT. I am going to have that door on the 69, but probably just going to make it a manual system where I get out of the car, open the hood, and push on a lever to put them up. As for my headlight, I drove it first three years after restoration with NO vacuum or electric. It takes 30 seconds to pull over, and push them up manually. When I get home, I push them back down manually. Simple. There is NO situation in which nightime sneeks up on me and I am suddenly driving in the dark.
Some Corvette owners like all these quirky systems and find joy in making them work......I am not one of them. Got better things to do.
Where do you get your information?
Once the door is open the electric wiper motor could care less about vacuum. Also the long hood started in 73.
I didn't say the wiper door system required vacuum.....the other poster , Mdbirk, did. Read above. It would be more appropriate to quote him, since he is the poster that made that satement. My statement was quoting him and providing a counterpoint.
As for when they started the long hood.....right, 73. I said my 77 had a long hood....and it does. To repeat....by 77 they had done away with the silly door system, and that is factually correct. I am fully aware the long hood started in 73.
Last edited by Shovels and Vettes; Mar 25, 2023 at 01:08 PM.
On my 1968 C3 after replacing the hose set the vacuum in the tank would last for several weeks. I could go out and pop the headlights up without running the car. When I used the headlights they would 'Pop' out almost instantly and this could happen a month or longer after the last engine run. For me it is a convenience to have a functional vacuum reservoir.
15 years after the vacuum hoses were replaced the head lights or wipers were still jumping to attention. I think the most important reason my system works so well is that when I bought my Corvette I had a set of Doc Rebuild's Vacuum hose set put on at my local Corvette restoration shop. I was a bit overwhelmed by the sheer number and volume of hoses my early 1968 Corvette came with from the factory. Using Quality parts and having them installed professionally was a smart move on my part.
My "Coffee Can" is painted flat black and is barely noticeable. It works great and provides benefits for the Corvette. If mine failed I would quickly replace it with another.
On my 1968 C3 after replacing the hose set the vacuum in the tank would last for several weeks. I could go out and pop the headlights up without running the car. When I used the headlights they would 'Pop' out almost instantly and this could happen a month or longer after the last engine run. For me it is a convenience to have a functional vacuum reservoir.
15 years after the vacuum hoses were replaced the head lights or wipers were still jumping to attention. I think the most important reason my system works so well is that when I bought my Corvette I had a set of Doc Rebuild's Vacuum hose set put on at my local Corvette restoration shop. I was a bit overwhelmed by the sheer number and volume of hoses my early 1968 Corvette came with from the factory. Using Quality parts and having them installed professionally was a smart move on my part.
My "Coffee Can" is painted flat black and is barely noticeable. It works great and provides benefits for the Corvette. If mine failed I would quickly replace it with another.
I think Zip Corvette sells a nice quality vacuum hose set. When I did have it in the car,.....before I ripped it all out and sold it,.....I bought hoses from Zip. Very nice quality and worked perfectly.
Thanks all, you shared the answer that makes sense in that it holds vacuum when the car is off. Since driving will be limited, having to start the car to get the headlights will do OK for the moment. I was hoping I could get them functional with the hose/actuator rebuild kit from Zip and hold off on the tank for now. Will be an eventual addition, but other priorities will come first. This is a super helpful forum, thank you!
No one has brought this up. But has been brought up many times in past threads.
with no vacuum canister. When you floor it and your vacuum drops to near zero. Your headlight relays will switch to the spring operated possition. Meaning that your headlights will pop up. And then go back down when vacuum resumes.
Many, many people on here over the years complaining about headlights that pop up when they floor it. Caused by a lack of vacuum to the headlight relay valves that control the headlight actuators.
no vacuum canister = headlight doors opening when you don't want them to.
No one has brought this up. But has been brought up many times in past threads.
with no vacuum canister. When you floor it and your vacuum drops to near zero. Your headlight relays will switch to the spring operated possition. Meaning that your headlights will pop up. And then go back down when vacuum resumes.
Many, many people on here over the years complaining about headlights that pop up when they floor it. Caused by a lack of vacuum to the headlight relay valves that control the headlight actuators.
no vacuum canister = headlight doors opening when you don't want them to.
Gonna reveal my lack of knowledge with this question so can be educated by an answer. The vac lines tap off the intake..flooring it means more air volume rate..and thus MORE vacuum....what have I got wrong here? Thx
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Its actually opposite of how you think it would be... in short with the throttle blades closed the engine just below the carb is trying harder to pull air past them so the engine sees more vacuum. with the throttle blades wide open the air is easily pulled in so just below the carb sees little vacuum....heres a thread I found if you want a detailed description https://www.stovebolt.com/ubbthreads...at%27s%20there.
In short your headlights would be winking as you drive the car, if you drive like I do.....full throttle, let off, coast, full throttle, let off, coast, stop, pull out of 50 foot driveway onto main road, full throttle, coast, pass the cop that is always waiting for me, full throttle, coast....etc...
I agree! I had an old car with true vacuum operated wipers. I thought they were dangerous. If you were driving in a rain storm on the highway and decided to pass a truck, the wipers slowed to the point they were useless. Jerry
Its actually opposite of how you think it would be... in short with the throttle blades closed the engine just below the carb is trying harder to pull air past them so the engine sees more vacuum. with the throttle blades wide open the air is easily pulled in so just below the carb sees little vacuum....heres a thread I found if you want a detailed description https://www.stovebolt.com/ubbthreads...at%27s%20there.
In short your headlights would be winking as you drive the car, if you drive like I do.....full throttle, let off, coast, full throttle, let off, coast, stop, pull out of 50 foot driveway onto main road, full throttle, coast, pass the cop that is always waiting for me, full throttle, coast....etc...
Got it. Full throttle has much more air passing through....but the open butterflies and more than offset provide much greater access to air thus decreasing the pull on the vac system..
I'm no expert, maybe I'm not completely right but just to clarify the wiper arm valve and the wiper door actuator are tied in to the vacuum system.
your way off, the wiper door operates with the vacuum system, wipers work with 12 volts, fail safe for wiper door is open, so wipers will work with no vacuum
OP,
Forum member Richard454 produces and sells kits to convert from vacuum actuators to electric headlight actuators and electric wiper door actuators.
No need for vacuum.
Richard’s Kits are top quality, he supplies excellent customer service, his kits are widely used by forum members and they are reasonably priced.
You didn’t supply any information about your 68, like, if it’s a big or small block engine or if the engine is stock or hi performance, or if you are running power brakes.
The reason I bring this up is, depending on your engine build and the camshaft grind it will effect the vacuum the engine pulls at lower rpm speeds.
On my 73, I’ve converted from the oem heating, ventilation and ac to a Vintage Air system which converts all the vacuum actuated controls to electric and I’ve deleted the windshield washers from my build as well.
The 73 has no wiper door and the wipers are electric.
I also converted from a TH400 automatic to a 5 speed manual, so no vacuum to the transmission module.
The only thing on my 73 which will run off engine vacuum will be my power brake booster and the distributor vacuum advance.
My point is, there are many things that run off vacuum in our cars, every model year can be different, so make sure your engine pulls enough vacuum to get you safely down the road while keeping your car running properly.
If you are simply removing the vacuum canister because it is unsightly, there are several aftermarket vacuum canisters that are brushed or polished aluminum or power coated, that look really nice.
Let us know what you end up doing and we always love pictures.
