C3 headlamp vacuum w/edelbrock 1406 help

[MikeB]

On my '76, I'm wondering if the manifold vacuum pressure is enough to operate my headlights properly.
They currently go up rather slowly, and will not retract on their own.
I do not have any vacuum gauges presently.
Currently, vacuum hose from manifold (circled green) leads out to brake booster with a diverter to the
headlight vacuum tank (front frame rail tube) tube circled in orange.



Now, to get the headlights to retract, with engine running, I need to pull the top hose off the actuator relay, and suck on the tube until
the headlamp clicks out of the full-extended position (only slightly down-ward). I then hook the tube back
up to the relay, and the headlamp closes. It requires quite a bit of human vacuum to get the downward motion started, more
than the current vacuum supply provides.
Not sure what my problem is, but I feel quite a bit of vacuum is required to get the units out of their "locked in up position".

I also wonder if I should be using manifold vacuum as shown in above picture, or should I be
using carburetor vacuum from the front of the carb? (Red circled area on carb which is plugged closed)


One oddity: When I remove the main feeder to the storage tank, and plug the end of the tube, my idle speed drops about 100 rpm.
Does this mean I have a leak at the storage tank?
Also posted at CFC3 tech support. Thanks for looking.

[StaticCling]

Unless you are running some insanely rowdy cam, there is no reason that the vacuum system shouldn't operate the headlights.

There is more to the Headlight Vacuum system than that tank. There are some actuators and relays that can wear out and cause problems. Also, there are many several hoses that can cause issues as well. Also check the Vacuum hoses on the switch under the dash, basically under the steering wheel.

I rebuilt the entire system on my '73 when I had mine. I was running a pretty healthy Isky cam on a built 350 with a 4150 Holley. When I rebuilt mine, the lights launched perfectly.

I would start with a Diagram and a new hose kit from Wilcox, Zip or Paragon.

Good Luck

[MadInNc]

Considering the beer you are drinking, Miller, you do suck . No Spotted Cow?

[Rodnok1]

Do we need to start a gofundme to get rid of that hideous air filter...

[StaticCling]

Originally Posted by Rodnok1

Do we need to start a gofundme to get rid of that hideous air filter...

Yeah. Get a drop base and run a traditional air filter, I agree.

[TheHammer]

should find your answer in here, lots of suckers

[StaticCling]

https://www.zip-corvette.com/73-79-h...yABEgJyafD_BwE

Start with this...

[ratflinger]

You should not be splitting the PB vac line. If that front port on that POS carb is manifold vac then I'd move the PB to the carb front and put a vac tower on the manifold where you currently get vac, for everything else.


Save up some money and have Lars build you a QJet & buy a good air cleaner.

[MikeB]

Originally Posted by StaticCling

Unless you are running some insanely rowdy cam, there is no reason that the vacuum system shouldn't operate the headlights.

There is more to the Headlight Vacuum system than that tank. There are some actuators and relays that can wear out and cause problems. Also, there are many several hoses that can cause issues as well. Also check the Vacuum hoses on the switch under the dash, basically under the steering wheel.

I rebuilt the entire system on my '73 when I had mine. I was running a pretty healthy Isky cam on a built 350 with a 4150 Holley. When I rebuilt mine, the lights launched perfectly.

I would start with a Diagram and a new hose kit from Wilcox, Zip or Paragon.

Good Luck

I have the vacuum diagram from Wilcox. This is how I bugged out the system.
I'm thinking the actuator relays may be bad, but is there a way to test it?.
I have (1) new actuator, and 1 old actuator. The new actuator light opens slower. A post over at CFC3 suggests relays may be bad too.
May just buy all 4 actuators and relays. About $250-300.
All hoses in the engine compartment and under the dash are in good shape. Pull down switch under column works as intended,as well as headlight switch. Just doesn't close the lights when pull down switch pushed up.

Saw that kit you linked, may order it at some point.

Originally Posted by MadInNc

Considering the beer you are drinking, Miller, you do suck . No Spotted Cow?

Champagne of beers when working.
NewGlarus SpottedCow/Totally Naked and Leinenkugels for relaxing/weekends.
Garage fridge

Originally Posted by Rodnok1

Do we need to start a gofundme to get rid of that hideous air filter...

Going out for paint next week.
Will buy a 10 or 14" Round open type chrome top filter after that.
Going to change fuel lines too.

Originally Posted by ratflinger

You should not be splitting the PB vac line. If that front port on that POS carb is manifold vac then I'd move the PB to the carb front and put a vac tower on the manifold where you currently get vac, for everything else.


Save up some money and have Lars build you a QJet & buy a good air cleaner.

This is the type of ideas I'm contemplating/looking for.
Thanks guys, much appreciated.

[Grey Ghost]

I imagine you could get a cheap vacuum gauge at Harbor Freight. Is it possible to hook it up to the hose, create some PSI, and let it sit to see if it leaks down the PSI? Similar to doing A/C evac./vacuum.

[Rodnok1]

I use my mitivac for a vacuum gauge if you have one Mike...

[Strats-N-Vettes]

Originally Posted by Rodnok1

I use my mitivac for a vacuum gauge if you have one Mike...

70's "gas saver" guage = vacuum guage.

[RHunt]

the vac tank is important.
must be able to hold vac.
until you get that done, the rest is not in play yet.
engine off, the tank vac should open the lights and close them.

[MikeB]

Found a leak this morning.
Went out to measure for new hose for PB booster, tested the check valve on the headlight ports, and the valve is open both ways.
Not good. Went to the local Napa, no luck, so I need to order the part. Should get it early next week.

Going to Harbor Freight to get a few gauges and test out the system. I got a link to a test procedure from CFC3 tech (Peterbuilt, wonder if he's here) that spells out testing every component, so that will be my next step once I get the check valve installed.

[MikeB]

Originally Posted by Rodnok1

Do we need to start a gofundme to get rid of that hideous air filter...

So, with no help from gofundme, I stopped in at the local AZ and bought this today:



As soon as I get the car back from paint, this baby is going in.
Sure to add a minimum of 5hp.

[Rodnok1]

10 if you put the sticker on also...

[DJ_Critterus]

Originally Posted by Touringmike

So, with no help from gofundme, I stopped in at the local AZ and bought this today:



As soon as I get the car back from paint, this baby is going in.
Sure to add a minimum of 5hp.

You didn't get the K&N filter to go with that?

[MikeB]

Originally Posted by Rodnok1

10 if you put the sticker on also...

Cheap ass bastards. No sticker.
I bought a Retro Radio, and they gave me a sticker, plus a XXL tee shirt.
Tee shirt has a silkscreened "Camaro" on the front.
Hey @Old Ben, do you want it? PM me an address.

Originally Posted by DJ_Critterus

You didn't get the K&N filter to go with that?

Off the shelf item,.
Just a plain white paper 'unspecified manufacturer' 14 x 3" filter.
Might replace it with a K&N element at some point.

[Old Ben]

Originally Posted by Touringmike

Cheap ass bastards. No sticker.
I bought a Retro Radio, and they gave me a sticker, plus a XXL tee shirt.
Tee shirt has a silkscreened "Camaro" on the front.
Hey @Old Ben, do you want it? PM me an address.




Off the shelf item,.
Just a plain white paper 'unspecified manufacturer' 14 x 3" filter.
Might replace it with a K&N element at some point.

Thanks for the offer but I will have to pass. I wear a Large.

[StaticCling]

You may need a fairly aggressive drop base for hood clearance. I think I was running a Performer RPM on mine and it required it.

Or you can just cut a hole.