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7/14/13 12:27pm - Original Message: 'Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
Would reducing the fitting on the manifold from 1/4" to 3/16" restrict the vacuum needed for the headlight actuators to work?  They both go up about 1/4" then stop. All hoses are new from Docrebuild.  I used the different size fitting because that's what I had on hand.  The bubba who installed this motor and vacuum lines had brake booster to manifold and headlights to carb...oops.  I thought it might be the headlight switch or bypass vavle as those are the oldest components in this system.   I'll probably get some vacuum line and bypass those two components to rule them out or in as the problem.

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Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
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7/14/13 4:22pm - Reply: 'Re: Vacuum restriction'
Redwingvette Lifetime Member
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Waterford, MI - USA

Vette(s):
1973 Red coupe

Joined: 9/13/2002
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The size of the line should not affect them. Clean and lube the barrings might help. See if one works better if you plug the line to the other. Check for vacuum leaks. Did you check the actuator valves? Also you will want to check the accumulator tank. Early years it was built into the bumper beam. Not sure when they changed it to a small can. The smaller fitting could cause it to take a little longer to go up but should not cause them not to move. Does it work any better after the car has been idling for a while? This would allow the accumulator tank to charge. 



|UPDATED|7/14/2013 2:22:04 PM (AZT)|/UPDATED|


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73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
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7/14/13 6:30pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201
Do you have a hot cam? 

Size, I mean, not whether or not it's stolen.  That's your bidness.  Wink


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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

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7/14/13 8:08pm - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
Longer idle doesn't make a difference.  I'll get my daughter to help me start checking for leaks.  I still need to try to bypass the light switch and bypass valve.  Wouldn't it be easy if it was the bypass valve?
 
...and NO the cam isn't hot, I swear, it was just sitting there the whole time, uh, I thought it was a present...No, not a high performance cam.  I'll guess slightly hotter than original, I don't have the specs in front of me, but no real lope.  Oh how we love THAT sound!


____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/14/13 8:25pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201

Sure sounds like you ain't got much vacuum in the tank.  Did they used to work, and just stopped?  If both stopped at the same time, you can bet it's not the actuators and relay valves as they're independent on all but the early C3s. 

Your original idea of jumping the headlight and bypass switches is a good one.  You can rule those out.  There should also be a small filter and check valve in line with the hose that goes from the manifold to the vacuum tank.  You can blow through them to make sure they're not bad. 


BTW, does your tank look like this?  You may want to check and make sure it isn't rusted through or has a split seam.  Plug two of the holes, and put a couple of pounds of air in it (not much!) and submerge it in water, and look for bubbles.





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- Brother Dave Gardner

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7/16/13 1:41pm - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
That's a good Idea.  What size coffee can should I use if mine is bad?Wink

____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/16/13 7:24pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201
Juan Valdez would be proud!

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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

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7/17/13 3:22pm - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
Well, I pulled mine out and tested it. No detectable leaks and I probably put a little too much pressure in it. I by-passed the headlight switch and by-pass switch and there was no change in action of headlights. There is still only a 1/2" movement up and then back down.  It seems strange that they would both act the same.  Any ideas, maybe the check valve or filter?

____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/17/13 7:34pm - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
OK, I reattached the headlight switch and bypass.  I have bypassed the resevoir.  Same problem. If I unplug the line that goes through the firewall and to the switch then plug that side of the check valve with my finger the lights come up 1/2".  when I reattach the hose, they go back down.  When I disconnect the vacuum line between the check valve and the filter, there by having no vacuum at all, they stay closed.
Anyone have any ideas before I tape flashlights to the hood?


____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/17/13 9:10pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201
You got me stumped.  You did say that they were both working fine, then both quit at the same time, right?

The only things in common for both headlights on your car are the main vacuum line to the reservoir and the vacuum line from the switch to the relays.  It sounds like the relays are working, as the lights begin to travel, but there is just not enough vacuum for them to move very far.  I'd test the main line going to the tank and blow through the filter to make sure it's not clogged.  Pull the bigger line off, blow it out well, and pressure test it and see what you find.  If you have a cheap vacuum gauge, maybe tee it into the main line going to the vacuum tank so you can see if you're getting a deep vacuum at the tank.

Or you could just begin drinking heavily.

:)



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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

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7/17/13 9:13pm - Reply: 'Re: Vacuum restriction'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
Dave, have the headlights ever worked right, or is this something that just started?
Both of them only rising a certain amount seems like it would be a loss of vacuum situation, but it could also just be that both of the actuators are leaking. Changing the size of the manifold fitting really shouldn't cause this, since you do have the reservoir. 
You can eliminate both the filter and the check valve as a test. The tiny plastic mesh filter screen can sometimes deteriorate, and clog the filter, so it might be restricting the available vacuum....not really a common problem, but it can happen.
Do you have access to a vacuum pump? If so, connect it directly to the actuators one at a time,a s see if the lights will rise/close properly.
I  have some headlight vacuum troubleshooting info I can e-mail you. Might help, might not, but it should give you a good idea of how the system is s'pose to work.


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Joel Adams
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7/17/13 9:13pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201
Just don't be this guy...




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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

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7/18/13 8:36am - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038

Joel, I got the email, thanks.  I'm going to try and track down a vacuum gauage and get busy.

The headlights did work, exceptionally well actually, prior to engine swap.  This isn't a super hp engine, just 330 and there aren't any other uses for the vacuum coming off the manifold and just one off the carb to the distributor.  The "mechanic" who installed the motor did screw up the vacuum lines and had the brake boost to the manifold and the headlights going to the carb. 
 
I'm going to pick up a cheap vacuum pump and test the actuators.
 
Darryl, where did you get that picture of my winter car?LOL


____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/18/13 10:14am - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
OK, here's an update.  I ran a line from the check valve to the relay valves to see what would happen...nada.  Then to the 't' I have in place of the resevoir...no change.  I hook everything up, sans resevoir and disconnect the hose going to actuators from the over ride switch.  I'm annoyed, it's hot, I throw gas on the car and light it up...wait, no, that was merely a vision.  I go over and lean on the front of the car and shazam, the gosh darn headlights open up.  WHAT THE ???
 
I hit the headlight switch on and the stay up.  OK, now I reattach the line for the bypass and they go back down.  I disconnect it and they open just a half inch.  Back to this.  I lean on the front again, here a noise and they go back up.  Then I take a closer look and they were getting stuck on the body...where's my gun!?
 
That solves part of the problem.  Now they go up but I have to use the bypass switch and clear their way so they don't hit the body. 
 
I'll ask about adjustiing the headkight doors on the body forum.


____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/18/13 11:19am - Reply: 'Re: Vacuum restriction'
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19459
Was the car up on jack-stands, or on a lift for while in the process of doing the engine swap? If so, that allows the front of the frame & bodywork to "sag"(or "bow", deepending on where the lift arms/jack stand were placed) from the firewall forward....it can cause all sorts of goofy stuff like this. Just don't set it on fire yet....LOL

____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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7/18/13 12:18pm - Reply: 'Re: Vacuum restriction'
dads2vette Lifetime Member
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Ash Fork, AZ - USA

Vette(s):
1981 Red Interior White exterior

Joined: 4/18/2007
Posts: 1038
It wasn't on jack stands during the swap.  It was during the exhaust install.  Buuut, jackstands in the back, ramps up front.  So, that shouldn't have caused any bowing. I have noticed the point at which the hood and boddy meet up at the front center of the car, do not meet up well.  The body is about 3/16" higher.

|UPDATED|7/18/2013 10:18:41 AM (AZT)|/UPDATED|


____________________________________
Dave C..........My mantra: I can not be bought!!      Long and short term leases available.
In the words of Zora Arkus-Duntov "Is your seat belt fastened? Alright, Let's go"


Yeah, I know, Shut up Dave.
Lifetime Member #192


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7/18/13 9:41pm - Reply: 'Re: Vacuum restriction'
dyoes
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Zachary, LA - USA

Vette(s):
1974 L-48 Auto. Just your basic Vette. GM crate motor w/vortec heads and intake. Crane cam. Scorpion rockers, Edelbrock carb. Lots of parts still in boxes... :(

Joined: 1/27/2013
Posts: 201
Wow... Didn't see that one coming.  I would have suggested that you remove the vacuum lines and manually travel them if ONE headlight had not been moving, but not two!  Goes to show ya.




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"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner

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