GM HEI discovery-Whaaaat? - Chevelle Tech
Performance Our High Performance area

 9Likes
  • 1 Post By Tommy the Cat
  • 1 Post By JKK
  • 1 Post By Schwany
  • 1 Post By engineguy
  • 2 Post By gnicholson
  • 1 Post By Hotwire
  • 1 Post By Schwany
  • 1 Post By mr 4 speed
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 14 (permalink) Old Feb 7th, 17, 10:10 PM Thread Starter
Tech Team
David
 
Join Date: Jan 2017
Location: S/E AZ
Posts: 209
Garage
GM HEI discovery-Whaaaat?

While nosing around under the hood of my recently acquired '69 SS w/ "454" today, I found another PO surprise. When I removed the dizzy cap and rotor to see what's what, I saw the PO had removed the mechanical advance weight springs and wired together the spring posts with some steel wire. So instead of springs to control the weights, they're now totally prevented from moving outward at any RPM(!) Why would anyone do this? (I'm using the dizzy's vacuum adv. can for idle quality btw) I don't know much about these HEIs, so any help is appreciated!

Last edited by Brownd3max; Feb 7th, 17 at 10:58 PM.
Brownd3max is offline  
Sponsored Links
Advertisement
 
post #2 of 14 (permalink) Old Feb 8th, 17, 12:24 AM
Lifetime Premium Member
Tom
 
Join Date: Oct 2006
Location: Firestone, CO
Posts: 1,161
Re: GM HEI discovery-Whaaaat?

It's a cheesey but easily reversed way to lock out the timing. It was probably set at around 36 degrees.
Brownd3max likes this.

70 Camino...Roller

69 Malibu Stock 307, Reverse Manual TH350, 4,500 Stall Edge Converter, 4.56 Spool 35 Spline 12 Bolt

76 C20 VortecPro 496 628HP 655 lb/ft TH400 Edge Converter, 4.10 14 bolt
Tommy the Cat is offline  
post #3 of 14 (permalink) Old Feb 8th, 17, 9:46 AM
JKK
Tech Team
JK
 
Join Date: Jan 2014
Location: Texas
Posts: 797
Re: GM HEI discovery-Whaaaat?

2xx
Brownd3max likes this.

67 El Camino ZZ 383 > FI-Tech F.I. / 700R4 /12 Bolt Posi 3.73s / P/S P/B A/C
" Rancheros the Other Short Bus"
JKK is offline  
 
post #4 of 14 (permalink) Old Feb 8th, 17, 11:33 AM Thread Starter
Tech Team
David
 
Join Date: Jan 2017
Location: S/E AZ
Posts: 209
Garage
Re: GM HEI discovery-Whaaaat?

OK guys, thanks for the info. I don't really understand the benefit of "locking out" the dizzy advance weights for normal street driving. Assuming that I should go back to springs, where can I source these? And how do I pick the right ones? Stock?
Brownd3max is offline  
post #5 of 14 (permalink) Old Feb 8th, 17, 11:37 AM
Senior Tech Team
Steve
 
Join Date: Sep 2016
Location: Seattle
Posts: 1,410
Garage
Re: GM HEI discovery-Whaaaat?

Quote:
Originally Posted by Brownd3max View Post
OK guys, thanks for the info. I don't really understand the benefit of "locking out" the dizzy advance weights for normal street driving. Assuming that I should go back to springs, where can I source these? And how do I pick the right ones? Stock?
You can get "timing curve" spring kits from Summit, Jegs and so on and so forth. One of the spring pairs in the kit will be stock, or close enough to it.
Brownd3max likes this.

'65 Chev El Camino
350/400+HP, 700R4
Edelbrock Pro-Flo 4 MPFI
Global West, QA1, Viking, Wilwood, UMI, ProForged
'68 P-11 Norton
Schwany is offline  
post #6 of 14 (permalink) Old Feb 8th, 17, 11:54 AM
Senior Tech Team
Bill R
 
Join Date: Aug 2002
Location: Gold Canyon, AZ
Posts: 2,807
Re: GM HEI discovery-Whaaaat?

You are correct, the vacuum advance should be functioning for street use. Replace the springs.
Brownd3max likes this.

Bill
64 Chevelle Malibu Sport Coupe (original owner) car now has 427" BB, Jerico 5-spd. trans., Dana 60 rear end.

SAE Member (25+ years)
ASE Master Certified Engine Machinist
AERA Certified Professional Engine Machinist
engineguy is offline  
post #7 of 14 (permalink) Old Feb 8th, 17, 11:00 PM
Senior Tech Team
Jeff
 
Join Date: Jun 2009
Location: Pittsburgh, Pa.
Posts: 2,057
Re: GM HEI discovery-Whaaaat?

You need to do that with a long duration cam with low idle vacuum.. Lock the distributor, make a mark on the balancer at 30 BTDC and use that mark to time the motor..

On points distributors, we used to just remove the springs and let the weights move out once the motor would start, the points spring would push them back when the motor was shut off and act as a start retard... It worked well..
hydro462 is offline  
post #8 of 14 (permalink) Old Feb 9th, 17, 12:57 AM
Senior Tech Team
Eric
 
Join Date: Sep 2011
Location: wisconsin
Posts: 1,926
Re: GM HEI discovery-Whaaaat?

Quote:
Originally Posted by Brownd3max View Post
\ dizzy cap, I'm using the dizzy's vacuum adv.
Are you trying to say DISTRIBUTOR?
dell72 is offline  
post #9 of 14 (permalink) Old Feb 9th, 17, 2:19 AM Thread Starter
Tech Team
David
 
Join Date: Jan 2017
Location: S/E AZ
Posts: 209
Garage
Re: GM HEI discovery-Whaaaat?

Yes, I am. The term "dizzy" is just a quick lazy way to spell "distributor". Another forum I've been a member of, (IH8MUD), uses that term frequently. You see, we off-roaders like short words. LOL!
Brownd3max is offline  
post #10 of 14 (permalink) Old Feb 9th, 17, 8:27 AM
Senior Tech Team
Gary
 
Join Date: Feb 2007
Location: Kansas City,Mo.
Posts: 4,349
Re: GM HEI discovery-Whaaaat?

how bout just use the abbreviation? in this case dist. ive seen people lock the advance when the weights and shaft pins wear out.
langss and lucifershammer like this.
gnicholson is online now  
post #11 of 14 (permalink) Old Feb 9th, 17, 8:32 AM
Senior Tech Team
Jeff
 
Join Date: Jan 2017
Location: Greensboring, NC
Posts: 1,077
Re: GM HEI discovery-Whaaaat?

Is there any type of adjustable ignition on the car? He could have the spark curve programmed into it instead of relying on centrifugal advance from the springs.
hydro462 likes this.
Hotwire is offline  
post #12 of 14 (permalink) Old Feb 9th, 17, 11:05 AM Thread Starter
Tech Team
David
 
Join Date: Jan 2017
Location: S/E AZ
Posts: 209
Garage
Re: GM HEI discovery-Whaaaat?

Hotwire & Gary- there's no added module/ box anywhere that i've found. And I've ordered a spring/weight/bushing kit to renew all that. I'm looking to go back to a "semi-standard" setup, with full manifold vac. advance for idle,(it was found plugged by PO), mech. advance using "stock" springs, and need to find a good static adv. setting starting point. How's 12* sound? More? Please advise!
Brownd3max is offline  
post #13 of 14 (permalink) Old Feb 9th, 17, 11:37 AM
Senior Tech Team
Steve
 
Join Date: Sep 2016
Location: Seattle
Posts: 1,410
Garage
Re: GM HEI discovery-Whaaaat?

Quote:
Originally Posted by Brownd3max View Post
How's 12* sound? More? Please advise!
That'll work. You may have to turn the idle screw way up though if that thing was locked out a 36*
Brownd3max likes this.

'65 Chev El Camino
350/400+HP, 700R4
Edelbrock Pro-Flo 4 MPFI
Global West, QA1, Viking, Wilwood, UMI, ProForged
'68 P-11 Norton
Schwany is offline  
post #14 of 14 (permalink) Old Feb 10th, 17, 2:49 PM
Lifetime Premium Member
 
Join Date: May 1999
Location: Under the hood of some musclecar
Posts: 28,107
Re: GM HEI discovery-Whaaaat?

Quote:
Originally Posted by Brownd3max View Post
How's 12* sound? More? Please advise!
Find out how much timing you are getting from the weights/springs before you settle on 12* starting point.
If you have 20* of mechanical advance,12* at idle/initial will not be enough.

Example: my car has 10* of mechanical advance and 25* initial for 35* total.
Brownd3max likes this.


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


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


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


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




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



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
mr 4 speed is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle 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, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 978 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
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