Headlight open/close speed?
Thread Starter
Instructor
Joined: Jun 2007
Posts: 205
Likes: 1
From: Miami, FL
Headlight open/close speed?
Assuming no mechanical issues like sticking hinges, what components determine the speed that the headlights open?
I'm thinking the vacuum pressure is probably the main thing, but even if it's boosted, would the actuators need to be adjusted somehow (and if so, how)?
I am thinking I'd like mine to snap! open/closed rather than slo-o-o-o-lllly eas. ing u-u-u-P-P-P.
I'm thinking the vacuum pressure is probably the main thing, but even if it's boosted, would the actuators need to be adjusted somehow (and if so, how)?
I am thinking I'd like mine to snap! open/closed rather than slo-o-o-o-lllly eas. ing u-u-u-P-P-P.
Last edited by ChrisMiami; Apr 30, 2014 at 11:47 PM.
Team Owner
Joined: Sep 2006
Posts: 31,274
Likes: 4,366
From: Westminster Maryland
Hi CM,
Assuming there is sufficient vacuum in the system, including the vacuum tank, once the actuators receive the open or close vacuum supply from the relays, it can only be the quality of the seal of the red and green hoses on the relay nipples and the actuator pipes, and the quality of the seals in the actuators, that determines how the doors react.
They can and should snap open and closed in unison.
Regards,
Alan
Assuming there is sufficient vacuum in the system, including the vacuum tank, once the actuators receive the open or close vacuum supply from the relays, it can only be the quality of the seal of the red and green hoses on the relay nipples and the actuator pipes, and the quality of the seals in the actuators, that determines how the doors react.
They can and should snap open and closed in unison.
Regards,
Alan
Last edited by Alan 71; Apr 30, 2014 at 06:03 PM.
Instructor
Joined: May 2012
Posts: 110
Likes: 4
From: Gainesville FL
Hi CM,
Assuming there is sufficient vacuum in the system, including the vacuum tank, once the actuators receive the control signals from the relays, it can only be the quality of the seal of the red and green hoses on the actuator pipes, and the quality of the seals in the actuators that determine how the doors react.
They can and should snap open and closed in unison.
Regards,
Alan
Assuming there is sufficient vacuum in the system, including the vacuum tank, once the actuators receive the control signals from the relays, it can only be the quality of the seal of the red and green hoses on the actuator pipes, and the quality of the seals in the actuators that determine how the doors react.
They can and should snap open and closed in unison.
Regards,
Alan
Pro
Joined: Aug 2013
Posts: 591
Likes: 3
From: Monroe Washington
Mine has a lazy right eye... Takes a few secs to pop up... There's lots of vacuum lines funning to and from those systems... And potentially, could be collapsing hoses...?
When I bought my vette the PO said he paid a bunch of money to have them fixed, but then a month later they just started staying up... He wasn't a mechanic himself and never looked into them... Every time I turned the lights off if hear a constant hissing under the dash, figured a hose had unplugged or failed... First time crawling under the drivers side I saw this little pull down plunger with vacuum lines running to it... Pushed in in/out a few times and wondered what it was for... Thought to myself , could it be THAT simple?
Fired up the vette, pushed in the plunger, and low and behold... The lights went down perfectly! And have ever since! Lol. It's been crazy how many 'issues' on my vette have been fixed by something soooo simple... Guess my PO had more dollars than sense ...
But anyways... If they're really sluggish, I might look into tracing all the vacuum hoses and putting fresh on to make SURE they aren't collapsing from age... Might be the cheapest/easiest thing to look at before checking diaphragms and mechanisms...
When I bought my vette the PO said he paid a bunch of money to have them fixed, but then a month later they just started staying up... He wasn't a mechanic himself and never looked into them... Every time I turned the lights off if hear a constant hissing under the dash, figured a hose had unplugged or failed... First time crawling under the drivers side I saw this little pull down plunger with vacuum lines running to it... Pushed in in/out a few times and wondered what it was for... Thought to myself , could it be THAT simple?
Fired up the vette, pushed in the plunger, and low and behold... The lights went down perfectly! And have ever since! Lol. It's been crazy how many 'issues' on my vette have been fixed by something soooo simple... Guess my PO had more dollars than sense ...
But anyways... If they're really sluggish, I might look into tracing all the vacuum hoses and putting fresh on to make SURE they aren't collapsing from age... Might be the cheapest/easiest thing to look at before checking diaphragms and mechanisms...
Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
I'm thinking you'll settle for having the pair open and close together in a reasonable time. The pair on my 80 open and close together in about five seconds or so; never timed it. The pair on my 68 start to open together, but the right slows down a bit. They close together.
I can live with it.
I can live with it.
Drifting
Joined: Jul 2006
Posts: 1,259
Likes: 154
From: Deplorableville Nebraska
what components determine the speed that the headlights open?
I'm thinking the vacuum pressure is probably the main thing, but even if it's boosted, would the actuators need to be adjusted somehow
Let me know if you want to fix yours......
Drifting
Joined: Sep 2010
Posts: 1,412
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From: Laguna Niguel California
"Assuming no mechanical issues like sticking hinges, what components determine the speed that the headlights open?"
The rotation of the earth, tidal conditions, the stock market and what you had to drink last night.
The rotation of the earth, tidal conditions, the stock market and what you had to drink last night.
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From: Orlando FL
[comedian Steven Wright]"If you were in your vehicle, traveling at the speed of light.... when you turn on your headlights.... would they do anything?"[/comedian Steven Wright]
Team Owner
Joined: Jan 2006
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From: Crossville TN
Slow headlights are usually due to bad seals in the vacuum relay(s) for the light buckets. You can check this out by simply bypassing the relay for each light.
Remove the main vacuum supply hose from the relay (center hose) AND remove both of the hoses on one of the headlight actuator cans. Hook the supply hose to one of the actuator can fittings (engine running, of course). The door will either OPEN or CLOSE; and, if you have a decent vacuum supply without much leakage, it should be pretty quick. Then, remove that hose and connect it to the other fitting. The headlight door should reverse direction...again, rather quickly.
If that all works as expected, you need to replace the vacuum relay unit for that light.
Remove the main vacuum supply hose from the relay (center hose) AND remove both of the hoses on one of the headlight actuator cans. Hook the supply hose to one of the actuator can fittings (engine running, of course). The door will either OPEN or CLOSE; and, if you have a decent vacuum supply without much leakage, it should be pretty quick. Then, remove that hose and connect it to the other fitting. The headlight door should reverse direction...again, rather quickly.
If that all works as expected, you need to replace the vacuum relay unit for that light.
Last edited by 7T1vette; Apr 30, 2014 at 05:16 PM.
Safety Car
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From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
orginal setup uses 1 pilot actuator for "each" headlight, which makes it very common for the lazy eye effect.
when I built mine I elected to use only 1 pilot actuator to open, both headlights at the same time.
I believe in later years GM moved to 1 pilot actuator, for both buckets also.
slow opening for both ? you most likely have other leaks to find.
best way to tackle vacuum problems, remove and plug the ports on engine side,
for ALL vacuum lines leaving the engine,
establish your best vacuum with a gauge, start adding back the vacuum acc.
if your base vacuum and fully connected vacuum are the same. you have no leaks.
when I built mine I elected to use only 1 pilot actuator to open, both headlights at the same time.
I believe in later years GM moved to 1 pilot actuator, for both buckets also.
slow opening for both ? you most likely have other leaks to find.
best way to tackle vacuum problems, remove and plug the ports on engine side,
for ALL vacuum lines leaving the engine,
establish your best vacuum with a gauge, start adding back the vacuum acc.
if your base vacuum and fully connected vacuum are the same. you have no leaks.
Last edited by 69Vett; May 1, 2014 at 10:46 AM.
Race Director
Joined: Jul 2001
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Try installing a vacuum gauge near one of the actuators. If the reading is not stable and very close to intake manifold vacuum levels, there's at least one leak.
Most people do nothing till the system stops working entirely and then only enough troubleshooting to get it somewhat functional.
I've seen very few cars that are 100% like new.
Thread Starter
Instructor
Joined: Jun 2007
Posts: 205
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From: Miami, FL
@DaveJ - darn right I wanna fix 'em! How do I ensure the new relays are quality parts?
Anyone know of a reference video that shows what "like new" acts like? I've seen plenty of anemic and lazy-eye examples, but nothing to make me say "now that's what it oughtta be"!
I've got a coil of silicone vacuum hose but I think the I.D. is too small, will get the right size when I can.
@7T1vette, @69Vett, @Mike Ward - thanks for the procedures, always welcome as I learn my way around.
Chris
How do I ensure the new relays are quality parts?Anyone know of a reference video that shows what "like new" acts like? I've seen plenty of anemic and lazy-eye examples, but nothing to make me say "now that's what it oughtta be"!
I've got a coil of silicone vacuum hose but I think the I.D. is too small, will get the right size when I can.
@7T1vette, @69Vett, @Mike Ward - thanks for the procedures, always welcome as I learn my way around.
Chris
Pro
Joined: Aug 2013
Posts: 591
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From: Monroe Washington
If mine go up and down... I don't really care about how 'fast' they are ... Now... Is it just me... Or does everyone else's headlights wiggle as you drive down the road and hit bumps ? Didn't know if THAT was inherent to the C3... Or something I should look into... Just has a slight vertical wiggle over bumps on the freeway...
Racer
Joined: Feb 2007
Posts: 337
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From: Clyde Ohio
FireballXL5 there shouldn't be a wiggle, you may want to look for a loose bolt or shaft wear. And tell me if I'm wrong, what gives the headlights the "snap" is the springs. The actuators only push them up or down but the actually should move at a constant rate through the length of the piston, the spring are giving it the quick snap. Grab the mechanism and move it manual, they will slam up and down. ChrisMiami your slow movement is another story, sounds like you needs to do a system tune up..
Last edited by tak82; May 1, 2014 at 07:48 AM.
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From: Austin Texas
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when the corvette headlights open to full extension, they pass over a cammed fulcrum point, backed up by a stiff spring, this setup,
and adjustment control the snap or Not, which is actually locking them into the open position,
if your headlight assy. wiggles you may other issues.
and adjustment control the snap or Not, which is actually locking them into the open position,
if your headlight assy. wiggles you may other issues.