Club Cobra GasN Exhaust  

Go Back   Club Cobra > Engine Building, Tuning, and Induction > Small Block Talk

Keith Craft Racing
Nevada Classics
MMG Superformance
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
Keith Craft Racing
MMG Superformance
Advertise at CC
Banner Ad Rates
Keith Craft Racing
MMG Superformance
May 2024
S M T W T F S
      1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31  

Kirkham Motorsports

Like Tree1Likes

Reply
 
LinkBack Thread Tools Rating: Thread Rating: 3 votes, 5.00 average. Display Modes
  #1 (permalink)  
Old 08-14-2007, 12:23 AM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default Ignition Timing and Webers

Those of you with Small Blocks (289/302) that have gone with Webers, what about the Ignition Timing. How much did you change it from your Holley set up? How did it respond or change things? I've read some information about it, but nothing confirming results with dyno or seat of the pants results etc?

Anyone????
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way

Last edited by Rick Parker; 08-14-2007 at 12:25 AM..
Reply With Quote
  #2 (permalink)  
Old 03-18-2012, 06:07 PM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Portland, OR
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,689
Not Ranked     
Default

Did you ever get an answer on this, Rick?
__________________
ERA FIA 2088
Reply With Quote
  #3 (permalink)  
Old 03-18-2012, 07:27 PM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default

Oh yes, 18-20 initial at 950 36 all in by 2600. Crisper than a bag of Doritos.
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way
Reply With Quote
  #4 (permalink)  
Old 04-03-2012, 05:45 AM
PoppyMod's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2010
Location: Severna Park, MD
Cobra Make, Engine: Ford 289
Posts: 50
Not Ranked     
Default

Quote:
Originally Posted by Rick Parker View Post
Oh yes, 18-20 initial at 950 36 all in by 2600. Crisper than a bag of Doritos.

Hi
It seems these carbs like a lot initial timing. I'm running dual 40 DCOEs on my 333 and are working very well. It responds very well with initial of 16-18 deg. Mine's all in by 3K.
What me distributor are you running and what is the mechanical?
Ken
__________________
Ken
Severna Park, Md
Reply With Quote
  #5 (permalink)  
Old 04-03-2012, 09:48 AM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Portland, OR
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,689
Not Ranked     
Default

I set mine at 18 a couple weeks ago. Waiting for a chance to give her a good breathe.
__________________
ERA FIA 2088
Reply With Quote
  #6 (permalink)  
Old 04-05-2012, 02:18 PM
jhirasak's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2012
Location: Redondo Beach, CA
Cobra Make, Engine: 331 SB, AFR heads
Posts: 75
Not Ranked     
Default

I set mine at 16 degrees initial and all in (36 degrees) at 3000. This is the same mechanical advance distributor timing that I used with the 715 Holly.
Reply With Quote
  #7 (permalink)  
Old 04-05-2012, 03:24 PM
j_b's Avatar
j_b j_b is offline
CC Member
Visit my Photo Gallery

 
Join Date: Jun 2007
Cobra Make, Engine: Superformance
Posts: 23
Not Ranked     
Default

38 degrees total advance all in around 2000rpm, and initial timing means next to nothing, per Jim Inglese.
Reply With Quote
  #8 (permalink)  
Old 04-05-2012, 10:49 PM
cab cab is offline
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2006
Location: torrance, ca
Cobra Make, Engine: hurricane,# 1060
Posts: 124
Not Ranked     
Default

38 deg. all in @2000 on my 289.
__________________
www.tni.com/craig-baker
Reply With Quote
  #9 (permalink)  
Old 04-08-2012, 07:16 AM
wolf k's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2010
Location: Augusta, MO
Cobra Make, Engine: Sold ERA FIA 2139, 331 Weber IDF
Posts: 279
Not Ranked     
Default

Yes, initial timing means next to nothing if you rarely run your engine below 2000 rpm.
But for those that do, 20 deg initial, 38 deg total by 2600 rpm works great for me. I did try a stock setting of 12-14 deg initial and 38 total and it sure did not run well in the lower rpm ranges, may have been able to tune it out with jetting, but when I went back to 20 initial, it ran like it was injected car. I do not know why weber IR carbs like a lot of initial timing. Anybody have a theory? I have zero pre ignition with 10.5 compression and 87 octane fuel

Last edited by wolf k; 06-12-2012 at 03:28 AM..
Reply With Quote
  #10 (permalink)  
Old 04-08-2012, 08:55 AM
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
Posts: 2,444
Not Ranked     
Default

Quote:
Originally Posted by wolf k View Post
I did try a stock setting of 12-14 deg initial and 38 total and it sure did not run well in the lower rpm ranges, may have been able to tune it out with jetting, but when I went back to 20 initial, it ran like it was injected car. I do not know why weber IR carbs like a lot of initial timing. Anybody have a theory? I have zero pre ignition with 10.5 compression and 87 octane fuel
My guess is that you are not running vacuum advance. Correct?
Reply With Quote
  #11 (permalink)  
Old 04-08-2012, 12:16 PM
wolf k's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2010
Location: Augusta, MO
Cobra Make, Engine: Sold ERA FIA 2139, 331 Weber IDF
Posts: 279
Not Ranked     
Default

Correct
Reply With Quote
  #12 (permalink)  
Old 04-08-2012, 02:10 PM
Gaz64's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2008
Location: Brisbane, QLD
Cobra Make, Engine:
Posts: 2,774
Not Ranked     
Default

Quote:
Originally Posted by olddog View Post
My guess is that you are not running vacuum advance. Correct?
There is the answer.

It's the difference between a 2D ignition map and a 3D map.

Vacuum advance should be utilised whenever possible, especially for a street car.

Race cars don't need it, it gets taken out to have one less part failure.
__________________
Gary

Gold Certified Holden Technician
Reply With Quote
  #13 (permalink)  
Old 04-09-2012, 07:21 AM
wolf k's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2010
Location: Augusta, MO
Cobra Make, Engine: Sold ERA FIA 2139, 331 Weber IDF
Posts: 279
Not Ranked     
Default

It's the difference between a 2D ignition map and a 3D map.

Understood

Plumbing a IR manifold for a vacuum source can be complicated, always wondered if you could use just one runner for the vacuum signal to the distributor. Anybody done this?
Reply With Quote
  #14 (permalink)  
Old 04-09-2012, 05:17 PM
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
Posts: 2,444
Not Ranked     
Default

600 rpm = 10 rev/sec = 5 intake strokes per second. Put a vacuum gauge on a single port and see how much pulsation you see. You might be able to dampen the pulsations by adding a vacuum canister in the line. However it will add lag time between when the vacuum changes at the engine and when you see the change on the other side.

Some guys on here have posted pictures of plumbing under the intake with stack injection. I have to assume the pulsation is a problem or they wouldn't go to all the trouble. I would say that EFI would be more sensitive to pulsations and lag time than timing would be.
Reply With Quote
  #15 (permalink)  
Old 04-09-2012, 09:18 PM
Rick Parker's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: California, Ca
Cobra Make, Engine: NAF 289 Slabside Early Comp Car with 289 Webers and all the goodies. Cancelling the efforts of several Priuses
Posts: 6,592
Not Ranked     
Default

I believe to do so would cause that single cylinder to run lean and be less responsive to tuning.?? JMO
__________________
Rick

As you slide down the Banister of Life, may the splinters never be pointing the wrong way
Reply With Quote
  #16 (permalink)  
Old 04-10-2012, 03:32 AM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Portland, OR
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,689
Not Ranked     
Default

That is a good point, Rick. In fact, wouldn't it effect all of tuning, even with a under manifold system? These carbs are very sensitive & the runners are very short. It's also not a big plenum that you are drawing from. It's a bunch of small lines
__________________
ERA FIA 2088
Reply With Quote
  #17 (permalink)  
Old 04-10-2012, 09:59 AM
wolf k's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2010
Location: Augusta, MO
Cobra Make, Engine: Sold ERA FIA 2139, 331 Weber IDF
Posts: 279
Not Ranked     
Default

A vacuum actuator on a distributor I would assume does not consume much vacuum(for a lack of better terms). Those guys that plumbed the runners together for a vacuum source did so perhaps to run power brakes, or maybe they needed a pcv valve connection, just guessing. I will try the vacuum gauge test as suggested. IDF carbs have a vacuum source tap.
Reply With Quote
  #18 (permalink)  
Old 04-10-2012, 04:49 PM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Portland, OR
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,689
Not Ranked     
Default

Let us know what you come up with
__________________
ERA FIA 2088
Reply With Quote
  #19 (permalink)  
Old 04-11-2012, 01:13 AM
Gaz64's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2008
Location: Brisbane, QLD
Cobra Make, Engine:
Posts: 2,774
Not Ranked     
Default

If you plumb all the runners with 1/8 line into a "log" then tap off with 3/16 to the advance diaphragm, you'll still get near equivalent average manifold vacuum to that of a single plane manifold.

The small lines don't make that much difference to carburettor balance.
__________________
Gary

Gold Certified Holden Technician
Reply With Quote
  #20 (permalink)  
Old 04-13-2012, 06:01 AM
wolf k's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Jul 2010
Location: Augusta, MO
Cobra Make, Engine: Sold ERA FIA 2139, 331 Weber IDF
Posts: 279
Not Ranked     
Default

Connected a vacuum gauge to the tap on the IDF carb, turns out that it is a ported tap. Had a nice steady needle, it was low at 7 in.hg at 1500 rpm, but only drawing from one cylinder. I do have a mild camshaft.
Reply With Quote
Reply


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
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 11:41 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink