vacuum lines - Pontiac GTO Forum

User Tag List

 
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old 04-11-2013, 04:43 PM Thread Starter
 
Join Date: Mar 2013
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
vacuum lines

Hi Guys,
Where is the proper place on the carburetor to hook up the vacuum advance line from the distributor on a 68 GTO with a quadrajet. Also where is the proper place to hook up the vacuum line to the hide away head lights.
Thanks,
Tom
tom miller is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 04-12-2013, 09:42 AM
 
jmt455's Avatar
 
Join Date: Mar 2012
Location: SE Michigan
Posts: 724
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Tom,
Are you using the original thermal vacuum switch with the 5 hose vacuum harness?

The original 68 distributor had a two-way advance unit. Vacuum was "switched" between the two sides of the diaphragm to advance OR retard the timing, depending on coolant temperature and engine vacuum levels.

Attached images show how to connect the original system.

If I remember correctly, there were 3 vacuum source feeds to the thermal vacuum switch. One was the hard line coming from front of the carb, the second was the hollow carb mounting stud (right rear stud; you can see it has a hose on it in the images) and the third was from the T fitting at the back of the carb. I don't remember exactly how the system was designed to work, but I remember that it would pull all the advance out at idle to reduce emissions.

There are two hoses that go to the vacuum advance unit on the distributor. One is attached to the capped nipple on the metal canister with the black plastic cap at the rear of the intake manifold.

The other hose the goes to the advance unit is the long hose coming out of the vacuum switch.

I hooked them up on my last 68, but I never tried to make the system work as originally intended. I plugged the vacuum hose going to the retard side of the advance can and used the advance side only. I ran directly from manifold vacuum. I retained the original switch, valve, canister and hose harness for concours judging purposes only.
Attached Thumbnails
Click image for larger version

Name:	68_vacuum_hose_connections[1].jpg
Views:	1220
Size:	165.6 KB
ID:	18601   Click image for larger version

Name:	68_vacuum_hose_connections2[1].jpg
Views:	1693
Size:	156.7 KB
ID:	18609  

1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base
jmt455 is offline  
post #3 of 4 (permalink) Old 04-12-2013, 07:04 PM Thread Starter
 
Join Date: Mar 2013
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
jmt455,
Thanks for the reply. I did not realize how complicated the stock system was.
I do not have the thermo switch and the vacuum advance control I have has only one connection to advance the timing.
I am connecting the distributor vacuum advance line to the vacuum outlet on the carburetor at the front right just above the throttle plates. If it is hooked directly to the intake manifold I think it would not work properly.
The hide away headlight vacuum source line I have hooked directly to the intake manifold in front of the carb.
Everything seems to work fine. I am just making sure I have everything hooked up right.
Tom
tom miller is offline  
post #4 of 4 (permalink) Old 04-12-2013, 09:09 PM
 
jmt455's Avatar
 
Join Date: Mar 2012
Location: SE Michigan
Posts: 724
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Tom,
The hideaway line was connected to one leg of the Top fitting at the rear of the carb, but what you did will work fine.

Connecting the vacuum advance lime above the throttle plates will not allow vacuum advanced at idle, but your engine might be happy with that. If not, you can try connecting the vacuum advance directly to manifold vacuum.

1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base
jmt455 is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO General Discussion

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO Forum 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 for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
1968, ? on vacuum lines 4 distributor supercab78 1964-1974 Tempest, LeMans & GTO Projects, Barn Finds & Restoration Discussions 3 12-16-2011 06:44 PM
AC Vacuum lines SIXT5GTO 1964-1974 Tempest, LeMans & GTO Projects, Barn Finds & Restoration Discussions 0 03-19-2011 02:12 PM
vacume lines SIXT5GTO 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 3 06-21-2010 12:00 PM
69 GTO fuel and vacuum lines jerry300ex 1964-1974 Tempest, LeMans & GTO Technical and Electrical Wiring 1 05-05-2008 07:22 PM
New Kitt lines: PEARL JAM The Lounge 3 12-01-2007 12:29 PM

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