The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-15-2002, 03:03 PM   #1
speeddemon
Registered User
 
speeddemon's Avatar
 
Join Date: May 2002
Location: lexington,South Carolina
Posts: 158
Angry Factory Tach Problems

Does anyone know where I can get my factory tach calibrated. It reads correct at idle but after that it is about 1000rpm over actual rpm. I have installed a HEI dist. would that be affecting it?

------------------
69-C10 LWB
__________________
69-C10 LWB
71- fleetside shortbed


It's a shame stupidity isn't painful

Never play leapfrog with a unicorn
speeddemon is offline   Reply With Quote
Old 05-15-2002, 03:07 PM   #2
Baradium
Binder Rep
 
Baradium's Avatar
 
Join Date: Jan 2001
Location: Salcha, AK
Posts: 1,506
Post

did the tach come from a 6 cyl truck?
Baradium is offline   Reply With Quote
Old 05-15-2002, 03:12 PM   #3
speeddemon
Registered User
 
speeddemon's Avatar
 
Join Date: May 2002
Location: lexington,South Carolina
Posts: 158
Post

I don't know I bought the whole instrument pannel at a swap meet. If it is can it be recalibrated?

------------------
69-C10 LWB
__________________
69-C10 LWB
71- fleetside shortbed


It's a shame stupidity isn't painful

Never play leapfrog with a unicorn
speeddemon is offline   Reply With Quote
Old 05-15-2002, 03:44 PM   #4
Blazer1970
Registered User
 
Blazer1970's Avatar
 
Join Date: Dec 1999
Location: Old Mission, MI, USA
Posts: 2,510
Post

These tachs are notoriously inaccurate. There is a screw on the back where you can adjust it. HEI will have some effect, but most of them are not accurate with points either.

------------------
Tim
__________________
Tim
Blazer1970 is offline   Reply With Quote
Old 05-15-2002, 03:53 PM   #5
71Chev
Senior Member
 
71Chev's Avatar
 
Join Date: Dec 2000
Location: Indiana
Posts: 3,074
Post

You can calibrate any factory tach, 6 or 8 cylinder tach with the calibration screw on the back of the tach. You will need another tach to compare to when you adjusting it.
I recalibrated my factory 6cyl tach against an aftermarket tach, on my 71 with HEI & V8. Works perfect.

------------------
  • 71 Chevy CST Long Fleet 350/350/3.07 leaf rear.
__________________
71 Chevy CST Long Fleet 350/350/3.07 leaf rear.
71Chev is offline   Reply With Quote
Old 05-15-2002, 04:35 PM   #6
bigvinnie
Registered User
 
bigvinnie's Avatar
 
Join Date: Aug 2001
Location: escondido, ca 92026
Posts: 1,222
Post

this is the tach adjustment screw....



------------------
'72 short step, 350, 700R4, tilt, ps, pdb, a/c, lowered coils, etc., other work in progress... San Diego, CA
http://www.ixpres.com/vlusardi/chevtrk.htm


[This message has been edited by bigvinnie (edited May 15, 2002).]

[This message has been edited by bigvinnie (edited May 15, 2002).]

[This message has been edited by bigvinnie (edited May 15, 2002).]
__________________
'72 short step, 350, 700R4, tilt, ps, pdb, a/c, lowered coils, etc., other work in progress... San Diego, CA

72 Stepside Project
bigvinnie is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 04:16 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com