vacuum advance - Team Camaro Tech
Tech 2000 Our previous General Forum
Replies ONLY - no new topics.

 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old Feb 3rd, 00, 02:10 PM Thread Starter
 
Join Date: Dec 1999
Location: arnold, mo, us
Posts: 26
Post

Does anybody run they're stock GM HEI without the advance hooked up? Can you just set your mechanical and leave it at that? Do you have to use the advance? Right now I'm running without it, and it doesn't seem any different
jokerdwarf is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old Feb 3rd, 00, 03:32 PM
Senior Tech
Johnny
 
Join Date: Dec 1999
Location: Rutledge, Tn.
Posts: 610
Post

joker my vacun advance went out & my 327 was hard on gas & had stumble & no power.

------------------
johnny
johnnyr is offline  
post #3 of 5 (permalink) Old Feb 4th, 00, 05:55 AM
Senior Tech
Gene
 
Join Date: Nov 1999
Location: Dallas, Texas
Posts: 1,659
Post

Your distributor will need to be recurved if you don't use the vacuum advance. I think you want your mechanical advance to come in much faster when you don't have vacuum advance. You won't get the best performance by simply disconnecting the vacuum advance.
gheatly is offline  
 
post #4 of 5 (permalink) Old Feb 4th, 00, 06:04 AM Thread Starter
 
Join Date: Dec 1999
Location: arnold, mo, us
Posts: 26
Post

Thanks guys....Ronnie
jokerdwarf is offline  
post #5 of 5 (permalink) Old Feb 6th, 00, 08:57 AM
Moderator
David Pozzi
 
davidpozzi's Avatar
 
Join Date: Nov 1999
Location: Central California, USA
Posts: 10,074
Post

You need a vaccum advance for street use. For full throttle applications you don't need the vaccum advance. The vaccum advance operates under higher vaccum conditions like part throttle crusing conditions. Less during 3/4 throttle, and not at all under full throttle. If you disconnect the vaccum advance on a stock distributor, your engine will be running retarded during part throttle conditions. This will cause the plugs to run cooler which will cause buildup of carbon deposits. Also your mileage will suffer and the engine could load up so much on a long trip it could stall. I had this happen to me! Full throttle performance will not change except where the carboned up plugs will misfire if too dirty.

If you recurve the mechanical advance correctly, you may be able to get by without the vaccum advance and only loose a little mileage. The usual problem is when the mechanical advance is modified to get better full throttle performance, the stock vaccum advance has too much advance and at too low a vaccum. The vaccum can needs to be changed to one with less total advance, or limited with a stop, and have a stiffer spring inside to come on only at higher vaccum. The typical symptom of an over active stock vaccum advance is a brief ping when accelerating from a stop. The vaccum advance opens all the way when you first open the throtle, then takes a little time to close as you get into the throttle and the vaccum drops. While the vaccum advance is closing the mechanical advance is opening (on a recurved distributor) and you get too much advance briefly, causing a ping. Regards, David
davidpozzi 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 not 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