Topic: Vacuum restriction
in Forum: C3 Engines
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Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
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
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.
Joel Adams
C3VR Lifetime Member #56 
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Lifetime MemberAsh Fork, AZ - USA
Joined: 4/18/2007
Posts: 1058
Vette(s): 1981 Red Interior White exterior
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?
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"
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Yeah, I know, Shut up Dave.
Lifetime Member #192
Lifetime MemberAsh Fork, AZ - USA
Joined: 4/18/2007
Posts: 1058
Vette(s): 1981 Red Interior White exterior
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.
Yeah, I know, Shut up Dave.
Lifetime Member #192
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
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
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....
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"
Lifetime MemberAsh Fork, AZ - USA
Joined: 4/18/2007
Posts: 1058
Vette(s): 1981 Red Interior White exterior
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|
|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.
Yeah, I know, Shut up Dave.
Lifetime Member #192
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.
"Let them that don't want none have memories of not gettin' any."
- Brother Dave Gardner
in Forum: C3 Engines
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