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Mechanical Dash Clock Adjustments

JimT

Member
Joined
Jan 11, 2007
Messages
17
Location
Cumming, Ga
Corvette
1972 Red Stingray
Does anyone know of a way to adjust the mechanical dash clocks on a C3? I have a '72 Stingray, and just removed, cleaned, oiled, burnished the contacts and reinstalled the dash clock, and it runs great. Now it's beginning to run too good - I'm gaining about 5 minutes every three days. I didn't notice any method of adjustment.

JimT
 
G

GaryS

Guest
I also own a 72 but it is stored right now but I think that there is something in the Owner's Manual about clock adjustment. If not there, then the GM Service Manual? I seem to recall that you wind the clock back 12 hours to lose some increment of time, maybe 2-3 minutes? The converse is true if you want to speed it up. It might be the CRS disease but I THINK that is how it works.

Gary
 
B

bmotojoe

Guest
Give this site a try,
http://members.aol.com/jjneyjr/clock/grepair1.htm
There are two pages associated to the repair of mechanical electric clocks for our C3’s. The first page is repairing the clock, and the second is on fine tuning and adjusting the clock to not gain or loose time. Sometimes this site is real slow, some times not, so give it a chance to load. They are working on a clock that looks like a 1976 but it may be from an earlier C3.
Brian
 

fine69

Well-known member
Joined
Dec 12, 2004
Messages
975
Location
Maryland / D.C.
Corvette
'69 Convertible Vette; '72 Z28 Camaro Rally Sport
Does anyone know of a way to adjust the mechanical dash clocks on a C3? I have a '72 Stingray, and just removed, cleaned, oiled, burnished the contacts and reinstalled the dash clock, and it runs great. Now it's beginning to run too good - I'm gaining about 5 minutes every three days. I didn't notice any method of adjustment.

JimT


Jim,

I just had mine rebuilt and upgraded to quartz by Harrison Speedometer in Florida. I understand that the quartz variety is supposed to keep time more accurately. I'm just happy that the clock is finally functional! :upthumbs

Harrison Speedometer did an excellent job. PM me if you're interested in using their service, and I'll give your their info....
 

Bill75

Well-known member
Joined
Jan 1, 2004
Messages
698
Location
Somers CT
Corvette
75 Coupe ZZ4, Brodix IK-180's, Headers,TK0-500
Jim,

I did my 75 clock a couple of years ago, took pictures and can't find them anywhere! There is an adjustment inside the clock to adjust the time, I think it's a slide lever or something, darn I wish I could find the pics. Anyway, I hooked mine up to a battery and let it run on the bench for a few days, each day adjusting it a little until it kept perfect time for a week. I put it in the car and a few weeks later it was gaining 5 minutes a day:D .

Bill

Edit: The site Brian posted shows the tensioning lever to adjust the speed.
 

Koop

Well-known member
Joined
Mar 16, 2005
Messages
545
Location
Kalifornia
Corvette
YELLOW 69 modified GM Crate ZZ383, LS2 TBSS
I went to quartz a long time ago.

Anyway, I seem to recall that you need to set the clock to the correct time daily (or everyother day then everyweek, basically everytime you see it's wrong) and that will correct the accuracy. I think you just do this using the pin on the front of the clock, just change the time.

Sounds like bull to me, but that's what I remember.
 

Evolution1980

Well-known member
Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
My clock wasn't keep very good time so I fixed that problem by replacing it with a transmission temp gauge. :L Much more informative now.

Besides, when I'm driving the vette, time is of no importance to me. :cool
 

chuck

Well-known member
Joined
Feb 7, 2001
Messages
193
Location
Tallmadge,Ohio
Corvette
1977 Dark Red Coupe/Buckskin 04 Spiral Gray/Gray
I went to quartz a long time ago.

Anyway, I seem to recall that you need to set the clock to the correct time daily (or everyother day then everyweek, basically everytime you see it's wrong) and that will correct the accuracy. I think you just do this using the pin on the front of the clock, just change the time.

Sounds like bull to me, but that's what I remember.

This is the correct way of adjusting a stock clock.
 

Bill75

Well-known member
Joined
Jan 1, 2004
Messages
698
Location
Somers CT
Corvette
75 Coupe ZZ4, Brodix IK-180's, Headers,TK0-500
This is the correct way of adjusting a stock clock.

I've done that to mine a hundred times and it's never made the clock run differently. Have you actually had good luck with this method chuck? The only thing I rember working was the F/S lever adjustment inside.
 

Evolution1980

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Messages
4,302
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Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
Bill75, Koop, Chuck, I think someone was either pulling your leg or just confused. Your clocks...mechanical, quartz, or otherwise (save digital)...all work on the same principal as the mechanical watch on your wrist. Have you ever heard that constantly adjusting the current time your wristwatch would make it more accurate? :chuckle Yeah, more accurate for the minute that you are adjusting to. But it doesn't adjust the actual mechanicals that keep time.
The only way to adjust for accuracy (that I'm aware of) is behind the scenes. On a wristwatch, that's by having a jeweler adjust the internals. Same goes with the clocks in the car, except that they may have an adjustment lever or something on the back. I'm not familiar with that method, but someone else had mentioned that adjustment might be there. I don't recall seeing one on my clock, but I didn't inspect it all that closely.
But in short, adjusting the clock from the regular front access needle I don't believe actually adjusts the internal accuracy +/-. It simply sets the current time just like it does on a mechanical wristwatch.
 

Bill75

Well-known member
Joined
Jan 1, 2004
Messages
698
Location
Somers CT
Corvette
75 Coupe ZZ4, Brodix IK-180's, Headers,TK0-500
Bill75, Koop, Chuck, I think someone was either pulling your leg or just confused. Your clocks...mechanical, quartz, or otherwise (save digital)...all work on the same principal as the mechanical watch on your wrist. Have you ever heard that constantly adjusting the current time your wristwatch would make it more accurate? :chuckle Yeah, more accurate for the minute that you are adjusting to. But it doesn't adjust the actual mechanicals that keep time.
The only way to adjust for accuracy (that I'm aware of) is behind the scenes. On a wristwatch, that's by having a jeweler adjust the internals. Same goes with the clocks in the car, except that they may have an adjustment lever or something on the back. I'm not familiar with that method, but someone else had mentioned that adjustment might be there. I don't recall seeing one on my clock, but I didn't inspect it all that closely.
But in short, adjusting the clock from the regular front access needle I don't believe actually adjusts the internal accuracy +/-. It simply sets the current time just like it does on a mechanical wristwatch.


Well.....actually this method does have some merrit only not in our clocks. I remember an old Plymouth my Dad owned that had a clock that would react to adjustments made in the time. I think the story may have been mis-applied to our clocks. But there is for sure a lever inside that will make changes in the way the clock keeps time..........I've used it. The trouble is you have to take the clock out to gain access to it.:eyerole
 

Evolution1980

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Messages
4,302
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Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
Well.....actually this method does have some merrit only not in our clocks. I remember an old Plymouth my Dad owned that had a clock that would react to adjustments made in the time
Hmmm..funky! :W
 

2VettesMike

Well-known member
Joined
Sep 27, 2006
Messages
131
Location
Blk Mtn, NC
Corvette
1972 Bryar Blue Coupe 1993 40th Coupe
If you want to stay original with the clock the web link above on how to clean and adjust the clock is the way to go. I used this information and it worked fine. It did take a 7-10 days of adjusting every day on the bench with 12V applied to the clock to get it adjusted. I used the lever in the article.

A couple of quick tips from my clock session. Use a can of low pressure clean air that you get at Radio Shack or some electronics place to get rid of the dust. If you use your compressor it will likely damage the tiny springs inside. Secondly when you adjust using the lever be careful not to bend it. When I did the bench adjusting I would use a watch with a seconds hand and basically restart the clock each day and compare the next day with the way to see which way to adjust. If you use any oil make sure it is a very light weight machine oil and use a toothpick to place it on the bearing points.

Results are 5 minutes of time lost in 3 weeks. The clock has been running perfectly since August.

Thanks

Mike
 
Joined
Nov 23, 2002
Messages
1,060
Location
Motorcity USA
Corvette
1973 L-48 Coupe
I bought the conversion to quartz kit and it has worked perfectly....the little gear that adjusts the time on it has worn out and i didnt think trying to fix that while I had it apart was worth the risk.
My vette is NOT an everyday driver...I pull the battery in the off season and when I put it back in , I wait for the right time and hook it up with in an hour or so, then tweek it in with the (worn gear) adjustment knob.
Everything in them is basically plastic or nylon and the gearing is very small, it wouldnt take much to toast it.
Why yours is gaining/loosing time is a mystery, rebuild kit is an hour or so job and like mentioned above, works perfectly.
Chas
 

Evolution1980

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Administrator
Joined
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Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
rebuild kit is an hour or so job and like mentioned above, works perfectly.
NOOOOO!!! You'll kill the NCRS value of the car!!!! It won't be worth as much to the next owner!!! :eek:hnoes:eek:hnoes :eyerole

;LOL
*sarcasm abounds*
 

Koop

Well-known member
Joined
Mar 16, 2005
Messages
545
Location
Kalifornia
Corvette
YELLOW 69 modified GM Crate ZZ383, LS2 TBSS
Bill75, Koop, Chuck, I think someone was either pulling your leg or just confused. Your clocks...mechanical, quartz, or otherwise (save digital)...all work on the same principal as the mechanical watch on your wrist. Have you ever heard that constantly adjusting the current time your wristwatch would make it more accurate? :chuckle Yeah, more accurate for the minute that you are adjusting to. But it doesn't adjust the actual mechanicals that keep time.
The only way to adjust for accuracy (that I'm aware of) is behind the scenes. On a wristwatch, that's by having a jeweler adjust the internals. Same goes with the clocks in the car, except that they may have an adjustment lever or something on the back. I'm not familiar with that method, but someone else had mentioned that adjustment might be there. I don't recall seeing one on my clock, but I didn't inspect it all that closely.
But in short, adjusting the clock from the regular front access needle I don't believe actually adjusts the internal accuracy +/-. It simply sets the current time just like it does on a mechanical wristwatch.

It does so.

Information with no cash value sticks in my head... So I dug out my owners book to check my memory.

From my 1969 owners manual:

Resetting the clock provides automatic regulation providing there is an error, either fast or slow, of at least 3 minutes. No regulation will be introduced if the clock is reset for an error of less than 3 minutes. When resetting, pull out the small knob and turn in the direction in which you wish to set the hands-clockwise if the clock is slow, counterclockwise if the clock is fast. Do not move the hands past the corrct time.

:harhar

I also believe this can take weeks or months to correct the regulation.
 

Evolution1980

Well-known member
Administrator
Joined
Feb 25, 2002
Messages
4,302
Location
Cleveland, Ohio
Corvette
ZZ4, 700R4, Steeroids rack & pinion, VB&P Brakes
It does so.
Resetting the clock provides automatic regulation providing there is an error, either fast or slow, of at least 3 minutes.
Hmmm..funky! :W
There's another thread about Q-jets where I was corrected today. Man, today is a great day!!! I've been wrong twice, which is good! ...because it means I learned two new things today! :D
 

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