Go Back  CorvetteForum - Chevrolet Corvette Forum Discussion > C3 Corvettes, 1968 - 1982 > C3 Tech/Performance
Reload this Page >

What happens when u drive without the vacuum advance connected?

Notices
C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

What happens when u drive without the vacuum advance connected?

 
Old 06-11-2006, 09:53 PM
  #21  
BarryK
CF Senior Member
 
BarryK's Avatar
 
Member Since: Apr 2004
Location: Newark DE
Posts: 7,108
Likes: 0
Received 20 Likes on 5 Posts
Default

Originally Posted by 77 zz4
We are still talking about hooking it up to the carb, right? The manifold vacuum nipple on my demon carb is currently capped. The ported nipple is hooked up to the trans (auto).
yes, if you have a full manifold source on your carb hook it up from there. if you don't you can pull it directly off the intake manifold itself by getting a connection from most of the parts suppliers or your local speedshop
BarryK is offline  
Old 06-11-2006, 11:12 PM
  #22  
77 zz4
CF Senior Member
Thread Starter
 
Member Since: May 2006
Location: hazlet township nj
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

I will try it after, but should I get a new vacuum can first? What will happen if I try it with the original can?
77 zz4 is offline  
Old 06-11-2006, 11:24 PM
  #23  
litevette
CF Senior Member
 
litevette's Avatar
 
Member Since: Nov 2002
Location: of mind
Posts: 2,371
Likes: 0
Received 0 Likes on 0 Posts
Default

Man I love these kinds of threads. Speacially the links some have provided. I'm certainly learning a lot! Thanks all!!!
litevette is offline  
Old 06-12-2006, 12:33 AM
  #24  
BarryK
CF Senior Member
 
BarryK's Avatar
 
Member Since: Apr 2004
Location: Newark DE
Posts: 7,108
Likes: 0
Received 20 Likes on 5 Posts
Default

Originally Posted by 77 zz4
I will try it after, but should I get a new vacuum can first? What will happen if I try it with the original can?
ZZ

check and make sure your timing is set correctly and adjust if needed.
check the fuel/air mixture on your carb via a vacuum gauge - the proper setting is usually when you get the highest reading of vacuum at idle.
connect up your existing vacuum can and recheck your timing and make sure that when it's all in it's around 50*-52* but make sure it doesn't exceed 52*. If your total timing with vacuum can attached falls around 50*-52* than your existing can should be fine.
BarryK is offline  
Old 06-12-2006, 07:58 AM
  #25  
77 zz4
CF Senior Member
Thread Starter
 
Member Since: May 2006
Location: hazlet township nj
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

By 52* do you mean 16* initial plus 36* @ 3200 rpm?

I'm a little below that now. 12* and then 36* @ 3200. Mind you, that is w/o the vacuum can.
77 zz4 is offline  
Old 06-12-2006, 08:38 AM
  #26  
BarryK
CF Senior Member
 
BarryK's Avatar
 
Member Since: Apr 2004
Location: Newark DE
Posts: 7,108
Likes: 0
Received 20 Likes on 5 Posts
Default

Originally Posted by 77 zz4
By 52* do you mean 16* initial plus 36* @ 3200 rpm?

I'm a little below that now. 12* and then 36* @ 3200. Mind you, that is w/o the vacuum can.
ok, if you are at 12* initial and 36* total now, AND you are not getting any pinging or knocking, than hook up the vaccum advance. AFTER you hook up the vacuum advance recheck timing and make sure it doesn't exceed 52* (36* total PLUS 16* vacuum advance).
I'm guessing on the 16* vacuum advance since I don't know what can you have but it should be close to that.

As long as you are between 48*-52* with the vacuum advance hooked up you should be fine.

**EDIT: don't forget to make sure you are have the vacuum line hooked to a full manifold vacuum source, not a ported source.

Last edited by BarryK; 06-12-2006 at 08:45 AM.
BarryK is offline  
Old 06-12-2006, 01:12 PM
  #27  
77 zz4
CF Senior Member
Thread Starter
 
Member Since: May 2006
Location: hazlet township nj
Posts: 122
Likes: 0
Received 0 Likes on 0 Posts
Default

Ok, I will try that later but, what happens if I'm not at 36 total?
77 zz4 is offline  
Old 06-12-2006, 01:32 PM
  #28  
BarryK
CF Senior Member
 
BarryK's Avatar
 
Member Since: Apr 2004
Location: Newark DE
Posts: 7,108
Likes: 0
Received 20 Likes on 5 Posts
Default

where is your total timing at if it's not at 36*?

anything below 34*-36* than it's too low, meaning it's retarded and you lose power, fuel economy, throttle response, and the motor runs hotter than normal.
If it's above 36* (some motors can get away with 38*) you are probably going to start hearing pinging and knocking from detonation. Detonation will kill your pistons quickly if you leave it at too advanced of a setting like that above 36*.
BarryK is offline  
Old 06-12-2006, 02:05 PM
  #29  
Fevre
CF Senior Member
 
Fevre's Avatar
 
Member Since: Mar 2001
Location: Living the Surreal Life in Ypsitucky MI
Posts: 11,323
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by BarryK
where is your total timing at if it's not at 36*?

anything below 34*-36* than it's too low, meaning it's retarded and you lose power, fuel economy, throttle response, and the motor runs hotter than normal.
If it's above 36* (some motors can get away with 38*) you are probably going to start hearing pinging and knocking from detonation. Detonation will kill your pistons quickly if you leave it at too advanced of a setting like that above 36*.

This it good for older heads but today's vortec or kidney shaped comb chamber heads like less timing. The ZZ4 has the old style comb chamber so 36 should be pretty much what you need
Fevre is offline  
Old 05-13-2019, 11:15 PM
  #30  
Mike Stansbury
Junior Member
 
Member Since: May 2019
Posts: 3
Likes: 0
Received 0 Likes on 0 Posts
Default vaccum advance

when mine is hooked up to full vaccum my idle stays way up and comes down very slow
Mike Stansbury is offline  
Old 05-14-2019, 11:04 AM
  #31  
zwede
CF Senior Member
 
zwede's Avatar
 
Member Since: Sep 1999
Location: Plano TX
Posts: 11,126
Received 205 Likes on 183 Posts
Default

This thread is from 2006. If you have a problem you want help with, start a new thread with more info.
zwede is offline  

Thread Tools
Search this Thread
Quick Reply: What happens when u drive without the vacuum advance connected?


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: