Club Cobra Keith Craft Racing  

Go Back   Club Cobra > Engine Building, Tuning, and Induction > Holley Tuning

Welcome to Club Cobra!  The World's largest non biased Shelby Cobra related site!

  •  » Representation from nearly all Cobra/Daytona/GT40 manufacturers
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and nearly 1 million posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

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
Keith Craft Racing
Keith Craft Racing
September 2020
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      

Kirkham Motorsports

Like Tree9Likes

Reply
 
LinkBack Thread Tools Rate Thread Display Modes
  #21 (permalink)  
Old 08-30-2020, 01:10 PM
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2020
Cobra Make, Engine: Backdraft #360
Posts: 50
Not Ranked     
Default

Quote:
Originally Posted by cycleguy55 View Post
Yes, that's the way an automatic choke operates. It will be fully open from when it was last run - the heating element in the choke pulls it open. After it's shut off the bimetallic coil cools and applies spring tension to the choke mechanism. The first touch of throttle will release the spring tension and pull the choke plate closed tight. Once it's started engine vacuum will pull the choke open to the set point of the choke pull-off mechanism. After that the bimetallic coil will continue heating while the ignition is on, allowing the choke plate to open further and further until fully open. There's also an interaction with the fast idle cam to keep the idle speed higher until the engine is warmed up.

More here: https://forums.holley.com/entry.php?...rel-Carburetor

This article has good instructions on adjusting carbs. It shows a pull-off adjustment you won't find on Holley's official pages - it's the adjustment I used on mine to make it run properly.
https://www.chevelles.com/threads/ad...#post-11389045
Thank you greatly. I'll be checking these out tonight. Appreciate the info on why the flaps are open at shutdown.
Reply With Quote
Sponsored Links
Sponsored Links
  #22 (permalink)  
Old 08-30-2020, 03:23 PM
Dwight's Avatar
Senior Club Cobra Member
Visit my Photo Gallery

 
Join Date: May 2001
Location: Florence, AL
Cobra Make, Engine: RCR GT 40 & 1966 Fairlane 390 5 speed
Posts: 4,421
Not Ranked     
Smile

cyclegue55 said WD-40 is for cleaning. I agreed.

A better lubricant is Kroil - An industry proven penetrating oil that has no equal

Penetrating-Lubricating Oils

Lots of places sell it.
Mattsvtcobra likes this.
__________________
''Life's tough.....it's even tougher if you're stupid.'' ~ John Wayne
"Happiness Is A Belt-Fed Weapon"
life's goal should be; "to be smarter than inanimate objects"
Reply With Quote
  #23 (permalink)  
Old 09-06-2020, 06:56 PM
Texasdoc's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2012
Location: Keller, TX
Cobra Make, Engine: Lonestar Classics LS427. Self-built 408W, AFR 195 heads, Performer RPM Intake, Quick Fuel 750, 407rwhp, 479rwtq
Posts: 543
Not Ranked     
Default

I use a thin coat of white lithium grease on the base plate and arms.
Reply With Quote
  #24 (permalink)  
Old 09-10-2020, 03:33 PM
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2020
Cobra Make, Engine: Backdraft #360
Posts: 50
Not Ranked     
Default

Quote:
Originally Posted by MaSnaka View Post
Do you have a mechanical timing advance on the distributor?? MSD. I noticed my RPMs were hanging up while lifting my foot. I cleaned and lubed the exterior of the carb (AED) and it would still happen occasionally. I had an epiphany and thought what if the mechanical timing on my distributor was hanging up. That would increase RPMs. So I popped the cap, everything looked good but I gave it a shot of wd40 where the weights and springs move. Problem gone so far. BTW- I have no vacuum advance on the distributor.

Hope this helps...
John
So I thought I had it all worked out. 1st ride after some WD-40, the problem was gone and it drove as it should. 2nd ride, it was doing what it was doing before and bogging bad. I took the air cleaner off and repositioned it a bit because its always hit the top of the distrib (working on getting a small riser to get it off of there) as well as opened the cap and closed it and the car ran great on the 3rd run. But any ride after has been where the RPMs climb.

Say I buy lube and not just use WD-40, put the air cleaner on a riser... Is there something I'm missing here?

EDIT: Just got back from a quick ride and the RPM's are not falling or fall slowly. I've tested all throttle linkage while in the garage and everything seems free. While on the ride, I used my big toe and the one next to it to grab the side of the pedal and it seemed to make the RPMs come down like they should.

*The weird thing is that on the past 5 trips when it was running good or bad I noticed one thing. If I felt it was good and the RPMs fell quickly, the car would run really well and responsive with minimal low RPM bog. If I felt it was running not so well and the RPMs would hang, there would be quite a bit more bog at the lower 2k range when I floor it. The engine would run a little more rough it feels and is noticeable in the car. Also, the start up would be almost instant if it was going to run well, and it would take some cycles for it to fire up if it was going to have not a good of a run.*

Last edited by Mattsvtcobra; 09-10-2020 at 05:13 PM..
Reply With Quote
  #25 (permalink)  
Old 09-11-2020, 08:18 AM
CC Member
Visit my Photo Gallery

 
Join Date: Aug 2007
Location: Carlsbad, Ca
Cobra Make, Engine: SPF 2932 with 438 Lykins Motorsports engine. Previous owner of FFR 5452.
Posts: 2,489
Not Ranked     
Default

Sounds like you’ve isolated the problem in the advance mechanism. One way to test if the timing is hanging up is to hook up a timing light and watch the timing pointer after blipping the throttle. Should snap back to initial setting. If slow to return then the advance is hanging up somewhere.
__________________
Jim
Reply With Quote
  #26 (permalink)  
Old 09-12-2020, 06:01 PM
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2020
Cobra Make, Engine: Backdraft #360
Posts: 50
Not Ranked     
Default

Thanks Jim! I will check with a timing light. Also someone in the ignition section suggested that I may have too strong of springs on the weights in the distrib, so I need to look into that too.


Question. The car drove decently today and had some hang up/RPM climbing on me when pushing in the clutch, but every time that happened I could pull the throttle back up with my foot and the RPMs would instantly drop to idle. Any idea what could be getting hung up? I've traced every thing on the throttle cable and I have 2 springs that seem to snap back well. Is there something I need to look into lubing or replacing?
Reply With Quote
  #27 (permalink)  
Old 09-14-2020, 08:06 AM
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2007
Cobra Make, Engine: # 757 ERA 427 SC , 482 Al. big block
Posts: 879
Not Ranked     
Default

I think you`re backwards on your distributor springs .... too weak will not pull the weights back as quickly and the advance will not return to the base setting quickly . The stronger weights will pull the weights back quicker , but also change your advance curve .
Check the MSD spring curves for where the advance comes in with the various spring combos . If your idle is too high , then it may have the advance already starting to come in .
Personally , I think you need to put a light film of lithium base grease under the weights to free them up and help keep corrosion to a minimum .
Mattsvtcobra likes this.
Reply With Quote
  #28 (permalink)  
Old 09-14-2020, 10:23 AM
cycleguy55's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2014
Location: White City, SK
Cobra Make, Engine: West Coast, 460 CID
Posts: 2,336
Not Ranked     
Default

I'd be concerned about using ANY kind of lubricant that would attract or hold dirt, carbon particles, etc. Clean the advance weight pivot points and either leave them dry or sparingly apply something like a dry film lube. Powdered graphite could work - if it wasn't conductive. I have a spray lube that has PTFE (Teflon) in it - the carrier evaporates and leaves the PTFE behind. The one I have is by GUNK Liquid Wrench, but WD-40 makes it, as do B'Laster, 3-IN-ONE and probably every other maker of general purpose lubricants.
__________________
Brian
Reply With Quote
  #29 (permalink)  
Old 09-14-2020, 12:48 PM
MaSnaka's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2006
Location: Thousand Oaks, CA
Cobra Make, Engine: Classic Roadster
Posts: 1,287
Not Ranked     
Default

Matt do you have a cable or linkage connecting the pedal to the carb?? When you say you lift the pedal and the RPM goes down sounds like there is a bind somewhere between the two. Then you say you can tell by start up whether it will run good or have the RPM hang up. Vac advance on the dist? Vac leak possible or bad diaphram?? The air cleaner should not be resting on the dist. I have the oval Cobra air cleaner and it clears my dist by about a 1/4" from the side but is nowhere near sitting on top. I have the FE motor which might make a difference. Does the air cleaner contact the choke horn?? Could cause air flow restriction on acceleration. Trying to think outside the box.

John
Reply With Quote
  #30 (permalink)  
Old 09-14-2020, 02:50 PM
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2020
Cobra Make, Engine: Backdraft #360
Posts: 50
Not Ranked     
Default

Quote:
Originally Posted by MaSnaka View Post
Matt do you have a cable or linkage connecting the pedal to the carb?? When you say you lift the pedal and the RPM goes down sounds like there is a bind somewhere between the two. Then you say you can tell by start up whether it will run good or have the RPM hang up. Vac advance on the dist? Vac leak possible or bad diaphram?? The air cleaner should not be resting on the dist. I have the oval Cobra air cleaner and it clears my dist by about a 1/4" from the side but is nowhere near sitting on top. I have the FE motor which might make a difference. Does the air cleaner contact the choke horn?? Could cause air flow restriction on acceleration. Trying to think outside the box.

John
Do you have a cable or linkage connecting the pedal to the carb?? When you say you lift the pedal and the RPM goes down sounds like there is a bind somewhere between the two.
--- It's weird, it seems to happen once the engine has warmed up. So something is changing when heat becomes a factor. That's why I wasn't sure if the carb had something that needed to be checked or lubed. Can a lubricant just be sprayed where I see levers moving and also down the throttle cable?

Then you say you can tell by start up whether it will run good or have the RPM hang up. Vac advance on the dist? Vac leak possible or bad diaphram??
---No vac advance

The air cleaner should not be resting on the dist. I have the oval Cobra air cleaner and it clears my dist by about a 1/4" from the side but is nowhere near sitting on top. I have the FE motor which might make a difference. Does the air cleaner contact the choke horn?? Could cause air flow restriction on acceleration.
---Mine does not clear. Not sure what you mean by the choke horn?


Trying to think outside the box.
--- I really appreciate it!
Reply With Quote
  #31 (permalink)  
Old 09-14-2020, 04:02 PM
MaSnaka's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2006
Location: Thousand Oaks, CA
Cobra Make, Engine: Classic Roadster
Posts: 1,287
Not Ranked     
Default

Hi Matt,
I use the silicone spray and lube the external moving parts on the carb with it on occasion, really not very often.

Air cleaner and choke horn- choke horn is the shroud surrounding the choke plates on the top of the carb. Rises about 1 1/2" above the carb opening. Some air cleaners being low profile to fit under the cobra hood, the inside of the air cleaner top is either making contact with the choke horn or very close to it. This can restrict air flow into the carb as you approach wot when the engine is sucking in the most air.

Do you have a phenolic spacer between the carb and the intake manifold? This insulates the carb from heat which might be causing some deflection in your linkages. I have only heard of them being used to prevent the fuel from boiling in the carb but maybe.

John
Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 11:59 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2020, 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