1967 Tach Adjustment - Team Camaro Tech
Electrical & Wiring Troubleshooting electrical.

 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old Mar 15th, 06, 11:08 AM Thread Starter
Tech Team
 
Join Date: May 2005
Posts: 30
1967 Tach Adjustment

Hi: I am just curious if anyone has ever adjusted their tach in the instrument cluster. I have a OER replacement tach that I just installed & it seems to be a few RPM's (about 50 to 70) low. Has anyone ever tweaked the adjustment before? Any ideas? Thanks in advance, Todd
tj1930vik is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old Mar 15th, 06, 11:19 AM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: 1967 Tach Adjustment

I have an oer 68 tictoc tach. not sure how accurate it is. It does have what looks like an adjustment screw on it's pcb. I've not dared to turn it. Let me know what happens if you do?





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #3 of 11 (permalink) Old Mar 15th, 06, 02:28 PM Thread Starter
Tech Team
 
Join Date: May 2005
Posts: 30
Re: 1967 Tach Adjustment

I haven't wanted to "tweak the tach" yet, either, until I hear if anyone else has had some luck.
tj1930vik is offline  
 
post #4 of 11 (permalink) Old Mar 15th, 06, 05:30 PM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: 1967 Tach Adjustment

someone posted briefly about adjusting a tach once, Farm Boy I think. Iaksed for details but they never appeared





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #5 of 11 (permalink) Old Mar 16th, 06, 08:02 AM
Senior Tech
Dave
 
Join Date: Apr 2001
Location: Southern NH
Posts: 1,052
Re: 1967 Tach Adjustment

I'm interested also if anyone knows how.
Dave69Z is offline  
post #6 of 11 (permalink) Old Mar 16th, 06, 08:22 AM
Gold Lifetime Member
Steve
 
Farm Boy's Avatar
 
Join Date: Feb 2005
Location: The California Republic
Posts: 1,718
Re: 1967 Tach Adjustment

These old tachometers have a calibration potentiometer on the circuit board that can be accessed through a hole in the back of the tach. If you remove the tach like I did you will need to hook up two wires and ground the unit. Be sure to use a plastic screwdriver to make the adjustment to avoid shorting out the circuits inside the tach. You can get a small plastic screwdriver at Radio Shack.






Steve

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

I drove it for the first time in 1972 when I was 15.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Better looking than a '56 Ford or Plymouth.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Farm Boy is offline  
post #7 of 11 (permalink) Old Mar 16th, 06, 10:47 AM
Gold Lifetime Member
Jim
 
Join Date: Dec 1999
Location: Yorkville, Illinois USA
Posts: 22,121
Re: 1967 Tach Adjustment

EXCELLENT! on my repro tictoc, the pcb is different, but the adjustment pot IS there. Now I just needa get a good reference tach, or do the math and use an osillascope (I do have one even if I don't know how to speel it!)

Anyone know how many msec's between pulses on a V8 coil wire @ 3000 rpm?





To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
New website for my vert is coming together. Do ya like the slide show on the home page?
JimM is offline  
post #8 of 11 (permalink) Old Mar 16th, 06, 02:05 PM Thread Starter
Tech Team
 
Join Date: May 2005
Posts: 30
Re: 1967 Tach Adjustment

I think the easiest way to spell oscilloscope is "o-scope". Works for me! A pulse count from the coil would be a great way to calibrate a tach. I think Farm Boy has a good idea about then plastic tweaker, too. Glad he mentioned it! Thanks, guys!
tj1930vik is offline  
post #9 of 11 (permalink) Old Mar 16th, 06, 02:13 PM
Gold Lifetime Member
Steve
 
Farm Boy's Avatar
 
Join Date: Feb 2005
Location: The California Republic
Posts: 1,718
Re: 1967 Tach Adjustment

My old tachometer was 50% fast before the adjustment!

I used an old analog Sun Tachometer/Dwell meter as a reference tach. I checked it out against the digital tach in my timing light and they were both identical through the entire scale.

I removed the tach from the dash. I used two jumpers to power the tach for the calibration. A third jumper for the ground would have been nice but I did not have one handy so I just grounded the tach to the shifter and made the adjustment. I adjusted it while holding the engine at 3000 RPM. The pot is sensitive so just a little movement makes a big difference. The tach is now the same as the reference tach from 600-5000 RPM.

I will repeat this warning: Use a plastic screwdriver because the tach circuit must be hot to calibrate it. This is especially important if you are making the adjustment without removing the tach from the dash. You don’t want to be blindly sticking a metal screwdriver through the adjustment hole and run the risk of shorting out your tach.


Steve

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

I drove it for the first time in 1972 when I was 15.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Better looking than a '56 Ford or Plymouth.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Farm Boy is offline  
post #10 of 11 (permalink) Old Mar 16th, 06, 09:08 PM
Senior Tech
Scott
 
Join Date: Apr 2005
Location: CA
Posts: 239
Re: 1967 Tach Adjustment

Good advice above. I adjusted my tach pretty much the same way using the digital tach on my smog machine as a reference.

Be sure to check it at more than one rpm. If the reading is off by a precentage (the error is greater at a higher rpm), turning the adjustment screw is the way to go. If it is off by the same amount at all rpm's, simply remove the needle and reposition it as necessary. If you are like me, it took a little of both to get it right.
red67camaro is offline  
post #11 of 11 (permalink) Old Mar 17th, 06, 05:15 AM
Senior Tech
Dave
 
Join Date: Apr 2001
Location: Southern NH
Posts: 1,052
Re: 1967 Tach Adjustment

Does anybody know if a 69 tach is adjustable? how does the needle come off?
Dave69Z is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome