Club Cobra Keith Craft Motorsports  

Go Back   Club Cobra > Engine Building, Tuning, and Induction > Weber 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
Keith Craft Racing
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
Win With A Cobra
Advertise at CC
Banner Ad Rates
Win With A Cobra
Win With A Cobra
Win With A Cobra
Win With A Cobra
August 2015
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          
  #1 (permalink)  
Old 09-19-2010, 06:39 AM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default Weber flooding issue

This one is a little more tricky than some of the Weber stuff I have sorted out in the past. I have checked and rechecked the float level. It is 24.5 mm from the tang to the top of the carb body without that e gasket and the float is around 5mm out of the carb body at that point. I think that is pretty close. My fuel pressure is just over 2lbs. Sounds good, right?

When it is cool and just warming up, everything is good but after tuning for a few hours there is a lot of heat built up in the engine and the carbs and my fuel is boiling in the boils. The gas is running out of the auxiliary venturi with some enthusiasm! Not good. I can turn the pressure done to 1lb and it still floods on two of the carbs, one more than the other but still.

Any thoughts? (and going to a 4 barrel or fuel injection doesn't count)

Could the brass float get so hot that the air inside would be lighter, requiring even lower fuel pressure and raise the float level to the point that the fuel just rushes in?
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
Sponsored Links
Sponsored Links
  #2 (permalink)  
Old 09-19-2010, 08:03 AM
Caprimaniac's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Sep 2006
Location: Skjetten, No
Cobra Make, Engine: Unfortunataly ; none
Posts: 331
Not Ranked     
Default

First off I would check: Are the extra thick carb gaskets (between manifold and carb)?

It has been discussed earlier, and this seems like a very good solution. I use 2 x standard gaskets after boiling gasoline after the engine was shut dow.
(Sure boiled when running as well, but I never saw this.) In this way the carbs are better insulated from the inlet manifold.

RS
Reply With Quote
  #3 (permalink)  
Old 09-19-2010, 09:18 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

Dean:
On the 427 FE, because the Carb mountings are angled at 10 degrees it causes issues that are not inherent in a SB application. Specifically when the carb is tilted towards engine centerline 10 degrees, the opening from the main well to the auxilliary venturi is lowered (compared to being mounted vertically)causing the fuel to drip, because the fuel (although level in the float chamber) is now higher towards the inside and lower towards the outside (of the bowl). Although it is possible that you have a couple of marginally acceptable fuel valves (needle/seat) I would continue to incrementally lower the float level until the dripping stops. The heat soak can be significantly reduced with the .100 thick gaskets available from various sources.

PS: With the carb top removed immediately after this happens remove the main jet assembly and see if you can visualise the fuel passage that connects from the Auxillary venturi to the jet assy. The fuel level in the well will need to be right at the bottom of this opening (after adjusting the float level) to prevent it from it drippping and to allow the mains system to transition without hesitancy. Clear as mud?
__________________
Rick

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

Last edited by Rick Parker; 09-19-2010 at 09:28 AM..
Reply With Quote
  #4 (permalink)  
Old 09-19-2010, 09:46 AM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

I was hoping you guys were around today. You gotta love these Weber's! I was checking my calibration tools and I noticed that they were a little off. The float is, in fact set a little high.

Next question.

My fuel pressure seems to raise at idle, past the range of the regulator like to 5 or 6 psi. It is a mechanical pump and I was wondering if the pulses from the mechanical pump could somehow "trick" the regulator. It is also possible that the gauge is messed up. I have 3 different gauges and I have no faith in any of them.
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #5 (permalink)  
Old 09-19-2010, 10:12 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,218
Not Ranked     
Default

if the fuel is pump gas that stuff is not designed for what you are doing. change the fuel.......something with a higher boiling point, i don't know if av gas would help, race gas is $$$$

insulate everything possible, fuel lines, 2x gaskets, etc.

get cool air into the engine bay, maybe some of those fancy hood vents.

sounds like you are trying to tune around a heat/fuel related problem.

i have no weber experience and this information is worth what you paid for it.....

how bout some pics just for trying?
Reply With Quote
  #6 (permalink)  
Old 09-19-2010, 11:31 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

Dean: Mine is stable at 2.5 from start, using Carter street rated (6#??) mechanical pump. If you have a fuel valve (Needle/seat) that is not sealing well when cold, (and alot of them have been faulted) then heat buildup may have some influece on it and cause it to seal better when warmed up?(?) The FE is going to be hotter under the hood, insulate the bases with the thicker gaskets and tune around the heat, no real viable way to eliminate it (?). I'd try getting the float level thing and dripping fuel issue resolved and you may find that will cure the other at the same time.
__________________
Rick

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

Last edited by Rick Parker; 09-19-2010 at 11:33 AM..
Reply With Quote
  #7 (permalink)  
Old 09-19-2010, 12:25 PM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

Vector, thanks for the tips. Here's a shot of the problem child!





Well, I checked the floats and they are correct now. I was sure I fixed it. The "tang" on the float was not level with the needle and seat. Due to the angle of the tang I thought it might not be closing all the way. Put it all back together, still leaking. I took it back apart, switch the needle and seat with the one next to it and it seems to be working as I adjusted the pressure back up to 2.5 -3 lbs.

I get what you are saying about the heat. I am going to order some more gaskets along with the Jaycee needle and seat assemblies. They are good to 9lbs!

Hell, I haven't even had a chance to do much with the jetting yet but that will come.
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #8 (permalink)  
Old 09-19-2010, 01:09 PM
CC Member
Visit my Photo Gallery
Original Shelby Owner


 
Join Date: Aug 2007
Cobra Make, Engine: 31XX Car
Posts: 339
Not Ranked     
Default webers

The newer weber needle valves are junk with a large proportion leaking out of the package. You need to put a vacuum gage on them and go through a bunch to get a good set. I custom made some in order to get acceptable sealing, large enough flow size and light enough balls. Your high fuel pressure at idle will also probably be a problem.
Reply With Quote
  #9 (permalink)  
Old 09-19-2010, 01:17 PM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,218
Not Ranked     
Default

very nice!!!!!

take your time........

since the fuel level sounds so sensitive maybe you could hook something up to put pressure on the fuel system without running the engine and then checking the level.

good luck

extra insulation might help with vibration if that could be a problem...
Reply With Quote
  #10 (permalink)  
Old 09-19-2010, 02:55 PM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

Well, it's all about the pressure. If the pressure is below 3, no leaks. Why in the f!@# is the pressure climbing! I have the Holley LOW pressure regulator! I am just about out of time. I'm leaving for Run and Gun Tuesday morning. Do I switch to an electric pump? Should I switch regulars? What are the other choices for a regulator? How about a return line?
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #11 (permalink)  
Old 09-19-2010, 03:30 PM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,218
Not Ranked     
Default

i vote for the return line, regulator can't maintain the differential between the two sides.......if that makes sense. plumb a quick line for a check.
Reply With Quote
  #12 (permalink)  
Old 09-19-2010, 05:56 PM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

I switched to an electric pump. It worked for a few minutes then right back to 6psi, washing down those new cylinders!

I have a 3 psi bypass regulator that I might put after the carbs and run that back to the tank. That HAS to work, right? If the first regulator falters, then the bypass should bleed off any build up at the carbs.

What regulator are you Weber guys running?
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #13 (permalink)  
Old 09-19-2010, 06:20 PM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Camels Hump, VT
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,421
Not Ranked     
Default

I can't see what you have between the carbs as a fuel line. It looks to be metal??? I know fuel expands when it gets hot. If you are filling hot metal tube with fuel after the regulator is it possible that it is expanding, raising pressure & over filling the carbs?
__________________
ERA FIA 2088
Reply With Quote
  #14 (permalink)  
Old 09-19-2010, 06:35 PM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

Hey Hyde, how have you been my friend?

The lines on the car are the cloth classic lines from Russell. I can try the return line tomorrow. I think I have enough parts in the garage for that.
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #15 (permalink)  
Old 09-19-2010, 07:21 PM
*13*'s Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2006
Location: Camels Hump, VT
Cobra Make, Engine: ERA FIA, 1964 289->Webers
Posts: 3,421
Not Ranked     
Default

Good, Thanks. Hope all is well there!

When I changed my Y-Manifold to incorporate the fuel log it cooked my fuel. It didn't effect my pressure reading but wouldn't idle for $#&@ when it got warm. I slotted the uprights eliminating some of the heat crossover. I don't know if heat has anything to do with your problem but sounds like you have been going down the list eliminating possibilities. Also seems to make sense that pressure difference may happen after regulator. I also run a mechanical pump with a regulator but on a much smaller powerplant.
__________________
ERA FIA 2088
Reply With Quote
  #16 (permalink)  
Old 09-20-2010, 07:35 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,218
Not Ranked     
Default

i run an efi fuel pump with regulator and return on a carb and have no problems maintaining 6-7psi, same principle as yours i would imagine. return line, return line, return line. plus the fuel will stay cooler running back to the tank rather then sitting in the engine compartment if that is where the regulator is located. i'm using a generic spring style regulator btw, they usually have a bypass port located on the body somewhere.

it wouldn't be right if you weren't doing these things at the last minute you know
Reply With Quote
  #17 (permalink)  
Old 09-20-2010, 08:19 AM
dlampe's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: May 2004
Location: centralia, IL
Cobra Make, Engine: B&B cobra (sold), Hurricane HMS1002 (sold), Kirkham 289 FIA, (sold) RCR GT 40(sold) SPF GT40 2122(sold) Hurricane HMS2002, (sold) RCR SLC (sold) GTR on the way!
Posts: 1,204
Not Ranked     
Default

I would love to be ready just once! It's always like this for some reason. Anyway, I found a shop that has a new regulator. I'm going to switch it out just to be sure. I am also running a return line to the tank with a bypass regulator after the carbs to relieve any spike in pressure that might occurr.

The crappy thing is even if I get this issue resolved, I still need to fine tune the jetting! Oh well, I leave tomorrow at 8 am so I have today and tonight. Sleep is over rated.
__________________
High Maintenance Racing Team
Run & Gun 2003 - 2011
www.runngun.us
Reply With Quote
  #18 (permalink)  
Old 09-20-2010, 12:26 PM
WildBill3's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Feb 2007
Location: Raytown, mo
Cobra Make, Engine: FFR Coupe SOLD.Current 66 Mustang
Posts: 960
Blog Entries: 1
Not Ranked     
Default

Good luck dean the return should help keep fresh low temp fuel fed to the beast,I only wish I had a few things to do like you .... have fun my freind
__________________
I agree Life is way to short to worry about gas milage.Other rides Crewcab Super Duty F350 Ford,Shlby Charger,66Mustang/Frankinstang,Chevy Van,KTM Dualsport,FFR Daytona Coupe SOLD... RUN N GUN 06,07,08,09 Hallet 09,
Reply With Quote
  #19 (permalink)  
Old 09-20-2010, 08:11 PM
Senior Club Cobra Member
Visit my Photo Gallery

 
Join Date: Jan 2000
Location: Frisco, TX
Cobra Make, Engine: ERA #122 (Sold) : Ford GT #484 Heritage Edition; 2008 GT500 Red/Black
Posts: 1,076
Not Ranked     
Default

Dean,

Are these NEW 48IDA's or old ones? I ask because itsonlymoney and I ran into this when they first started making the new ones.

God I have to think back its been 5 years. The new 48's use a push in pump jet instead of the screw in type that I had in the older style.

On 289's without the 10deg this doesn't cause a problem but the newer ones the little BB they use inside the squirter doesn't always seat properly because they use a flat piece of brass with a hole in it. Think of those games that drove us nuts as kids where you try to get the bb in the little hole of cardboard. Well it doesn't always go in the hold and that means that you don't shut off the fuel and sometimes a drip down the cylinder sometimes a stream.

The solution was david took the thing apart and used a small drill bit to just barely ream a little bit of a dish to the base so the ball always seated over the hole...problem solved. It almost sounds like what you are having...it will drive you NUTS! and took forever to figure out what was causing it because it does lead you to believe that you have either too much pressure or the floats are too high and they are leaking.

Matt
__________________
2006 Ford GT #484 Heritage Edition
2003 Hummer H1 OpenTop
2003 Hummer H1 Wagon
Reply With Quote
  #20 (permalink)  
Old 09-21-2010, 04:02 AM
CC Member
Visit my Photo Gallery

 
Join Date: Dec 2004
Location: Kansas City, KS
Cobra Make, Engine: jbl
Posts: 2,218
Not Ranked     
Default

well he's leaving this morning, anybody wanna give odds?
Reply With Quote
Reply

Thread Tools
Display Modes

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 01:33 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2015, 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