Wcfb question
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
Wcfb question
I have replaced the Rochester 4-Jet carb on my '62 327/250HP with a correct date coded original WCFB. I've tuned and retuned this carb many times, to the point where I can pump the accelerator once, have the engine start and idle effortlessly. In nuetral I can rev the engine to red line with no bog or hesitation. However under load, the engine bogs down and I get minimal acceleration when the pedal is floored. In normal driving situations the engine performs well. I thought the Carter would give me the same or better performance that I got from the Rochester. My question is what am I doing wrong or is it the carb itself? 
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
I'd get a manual and check the metering rods. Also check the float levels.
Is your throttle rod pulling the butterflies all the way open?
That carb should run about the same as the Rochester.
Is your throttle rod pulling the butterflies all the way open?
That carb should run about the same as the Rochester.
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
Just checked the WCFB...I have a strong pump squirt & the butterflies open all the way...As I stated...at idle with no load this engine will scream just like when I had the Rochester on, but under load I can only get it up to aprox 4500 RPM then when I shift it's fine until I get up to aprox 4500 RPM again...could the trouble be the timing instead of the WCFB??
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Just checked the WCFB...I have a strong pump squirt & the butterflies open all the way...As I stated...at idle with no load this engine will scream just like when I had the Rochester on, but under load I can only get it up to aprox 4500 RPM then when I shift it's fine until I get up to aprox 4500 RPM again...could the trouble be the timing instead of the WCFB??
What did it run like before you changed over and what all did you disturb?
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Just checked the WCFB...I have a strong pump squirt & the butterflies open all the way...As I stated...at idle with no load this engine will scream just like when I had the Rochester on, but under load I can only get it up to aprox 4500 RPM then when I shift it's fine until I get up to aprox 4500 RPM again...could the trouble be the timing instead of the WCFB??
Float level and fuel flow to carb are also considerations....if the float is way too low....the bowl will only fill so far.
Jebby
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
It ran like a "neck snappin'" 300 Horse!!
I didn't disturb the plugs..just readjusted the timing, and swapped in a new air filter. I think Jebbysan might be on to something ..maybe it's starving for fuel under load..Just "crusin'" it's fine..but I want that "Kick in the Pants" back...so install new springs??
Race Director
Joined: Jun 2006
Posts: 17,901
Likes: 751
From: Inverness FL
St. Jude Donor '07
It ran like a "neck snappin'" 300 Horse!! I didn't disturb the plugs..just readjusted the timing, and swapped in a new air filter. I think Jebbysan might be on to something ..maybe it's starving for fuel under load..Just "crusin'" it's fine..but I want that "Kick in the Pants" back...so install new springs??
I didn't disturb the plugs..just readjusted the timing, and swapped in a new air filter. I think Jebbysan might be on to something ..maybe it's starving for fuel under load..Just "crusin'" it's fine..but I want that "Kick in the Pants" back...so install new springs??Bill
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Metering rods mis-adjusted or the spring not pushing the rods out of the jets will do the same thing.
Never seen weak springs but there's a lot I haven't seen.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
This is a kick *** site.....lots of good info here:
http://www.capital.net/com/studiog/CarterWCFB/
Jebby
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
O.K. Let's start with the easy stuff..the springs...are they easy to find for an old carb like this? Any of the "Corvette parts suppliers" carry these, do you think NAPA has them? Or is it more of a "specialty carb" thing?? Also thanks guys for all the helpful info..much appreciated!!
Last edited by corvette-62; May 12, 2012 at 04:17 PM. Reason: Thanks
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Just check for good spring back and freeness.....if the rods snap up good and quick....move on.....
Read the link I showed you....great info with pics!
Jebby
Le Mans Master
Joined: Feb 2008
Posts: 5,214
Likes: 447
From: NJ Hockey beer league
Air horn needs to come off and re-check your float level (which I am thinking is set TOO LOW). Here is a picture of the correct Kent Moore original tool from my collection which works like a charm. Re adjust the floats and I think your problem will be soved.
Pilot Dan
Pilot Dan
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,145
Army
ABSOLUTELY check the timing as MikeM suggested before tearing into one of these carbs...a loose distributor hold down bolt could be all that is wrong. THEN check the float level and the vacuumeter plunger (the leather or rubber disc that gives these old carbs their pump shot)....you may appear to have a nice stream when the car is sitting but its not enough under load. This part can deteriorate over time.
And only AFTER THAT screw with springs, metering rods, etc.. The springs in this carb are hardly under much stress and I've never had one give me a problem unless its the WRONG spring. Low vacuum, 'cam' cars like Duntov 270HP have less aggressive springs to make things work easier.
Here are the troubleshooting pages from the old Packard WCFB manual; its the same carburetor basically. I doubt Packard Inc. is worried about these being posted electronically at this point. www.daytonaparts.com has very nice rebuild kits that are setup for modern fuel... You will never find those old float gauges that Pilot Dan has so you just have to eyeball it some other way as I do.
And only AFTER THAT screw with springs, metering rods, etc.. The springs in this carb are hardly under much stress and I've never had one give me a problem unless its the WRONG spring. Low vacuum, 'cam' cars like Duntov 270HP have less aggressive springs to make things work easier.
Here are the troubleshooting pages from the old Packard WCFB manual; its the same carburetor basically. I doubt Packard Inc. is worried about these being posted electronically at this point. www.daytonaparts.com has very nice rebuild kits that are setup for modern fuel... You will never find those old float gauges that Pilot Dan has so you just have to eyeball it some other way as I do.
Last edited by Frankie the Fink; May 13, 2012 at 06:20 AM.
Burning Brakes
Joined: Jul 2010
Posts: 755
Likes: 8
From: delco pa
ABSOLUTELY check the timing as MikeM suggested before tearing into one of these carbs...a loose distributor hold down bolt could be all that is wrong. THEN check the float level and the vacuumeter plunger (the leather or rubber disc that gives these old carbs their pump shot)....you may appear to have a nice stream when the car is sitting but its not enough under load. This part can deteriorate over time.
And only AFTER THAT screw with springs, metering rods, etc.. The springs in this carb are hardly under much stress and I've never had one give me a problem unless its the WRONG spring. Low vacuum, 'cam' cars like Duntov 270HP have less aggressive springs to make things work easier.
Here are the troubleshooting pages from the old Packard WCFB manual; its the same carburetor basically. I doubt Packard Inc. is worried about these being posted electronically at this point. has very nice rebuild kits that are setup for modern fuel... You will never find those old float gauges that Pilot Dan has so you just have to eyeball it some other way as I do.
And only AFTER THAT screw with springs, metering rods, etc.. The springs in this carb are hardly under much stress and I've never had one give me a problem unless its the WRONG spring. Low vacuum, 'cam' cars like Duntov 270HP have less aggressive springs to make things work easier.
Here are the troubleshooting pages from the old Packard WCFB manual; its the same carburetor basically. I doubt Packard Inc. is worried about these being posted electronically at this point. has very nice rebuild kits that are setup for modern fuel... You will never find those old float gauges that Pilot Dan has so you just have to eyeball it some other way as I do.
use the manual just posted, and go thru the carb again,,, teh procedures are in there, just check that the measurements are right for your carb...
Thread Starter
Pro
Joined: Aug 2010
Posts: 578
Likes: 11
The 2 things that are a PIA (read "clueless") for me on my '62 are electrical and carburators. It now seems that before I take this WCFB off the manifold I should focus more on the floats that need adjusted. I get the impression I'm running too lean. In reading the replys I'm getting the sense that I need some sort of meetering tool for adjustment(?). Am I able to adjust the float without taking the carb off the manifold? Anybody have the time/patience to walk me through this?.... Hey Frankie wanna come back to Pittsburgh??
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
The 2 things that are a PIA (read "clueless") for me on my '62 are electrical and carburators. It now seems that before I take this WCFB off the manifold I should focus more on the floats that need adjusted. I get the impression I'm running too lean. In reading the replys I'm getting the sense that I need some sort of meetering tool for adjustment(?). Am I able to adjust the float without taking the carb off the manifold? Anybody have the time/patience to walk me through this?.... Hey Frankie wanna come back to Pittsburgh??
Undo the fuel line......remove all of the air horn screws.....crack the
airhorn lid from the base.....lift gently...at this point rotate the lid until
you can wiggle out the accelerator pump rod......
From there follow the float drop instructions from the website I posted.
I am ruling out timing because it was ok before you swapped carbs....
It would have to be grossly retarded to make the engine not rev.
Jebby