John, Tom and Frank are great resources on these WCFBs. I see you rebuilt them yourself which is good, they are straight forward. Download that manual that Frank suggested.

Check the pump pressure as Frank suggested.

Take the little cover off over the metering rods while the engine is running. At idle the 'T' bar where the metering rods hang should be DOWN (pulled down by the vacuum). As you accelerate (vacuum decrease) the ''T' will raise the rods to expose the smaller diameter on the rod in the jet.

If the spring is too stiff, the 'T' will not lower at idle. There are two different springs for the 'T'. One for std cam vacuum and weak one for low vacuum more radical cams.

Just to reinforce others comments these WCFB 2 x 4s are great set-ups. I have run mine for 48 years and 200,000 miles. It starts and runs like it was EFI. A couple of years ago I did a STEALTH engine by putting a DART 400 and DART HEADS with all my original 1961 components back under the hood including the WCFBs. It dynoed 496 hp and 460 ft lb.

Best is the WOW factor when people see those old WCFBs

Joe

 

I appreciate the support and the manual is very helpful. The floats, to me, are an avenue that I will check carefully. They could easily have been bumped along the way and cause some difficulty. At a minimum the fix for the stalling should be done anyway. I think in the end, I will get this solved, it's just frustrating to try and isolate the problem. I really appreciate all the supportive comments about these being potentially okay. I was ready to pitch them in the lake in front of my house!

 

I had a running rich problem on my 61 with 2x4's. The way I
figured it out was with an IR heat gun. The rear cylinders 6-8 5-7 were
running at 500+ degrees on the exhaust manifold. Fast idle (1000) rpm
The front 4 cylinder were running at 200+ degrees. I cranked down
the idle screws on the front carb until the were closed. The temp on
the front cylinder came up to the 500 degree level. I backed off the
front idle screws until the temp on the front cylinders started to go down.
The final setting on the front carb was about 1/16 turn from closed.

Hope this helps...
Ray

 

Ray, that is good idea. That is the way I have shown 'the boys' to identify a dead cylinder on the big recip airplane engines. You have just digitized the diagnosis (no burnt fingers) with you heat gun !

Joe

 

CWalley ....... not trying to rush you .... but have you resolved your problem ... or has time been a problem ... I can understand the latter.

 

I've had similar running rich and high idle problems and could not for the life of me work it out. So had a friend over today (and a second pair of eyes and ears make a big difference). What we found is a number of vacuum leaks - as follows:

1. Secondary carbi small leak under the gasket - replaced gasket
2. Secondary carbi rather large leak around the secondary butterfly shaft on the left side where the shaft does extend out past the base casting (shaft sits about 1/8" inside the housing) - fixed this by cutting a small round disk out of gasket paper and placing this against the shaft and filling the remaining 1/16" with metal set.
3. Remaining primary and secondary butterfly shafts are all a bit worn where they rotate in the base casting and suck in air I WILL NEED TO GIVE THIS SOME ATTENTION .... going to a machinist mate of mine and talk bronze bush inserts ... which means machining out the base casting at the shaft points.

How did we find all of these leaks ... with a garden hose and a good stream of water over the carb bases. I had done this before with a spray bottle but water quantity is the key. Had the motor running and allowed the water to run over the carbi base and manifold and everytime the idle dipped new vacuum leak was found. Runs better now already with the fixes made (points 1 and 2) but still running a bit rich and the idle screws are almost backed completely off. In fact some of the vacuum leaks past these shafts are so big the engine practically stalled when the leaks was momentarily stopped by water.

Also still runs a bit hot ... may need to change the thermostat or drill some holes in it.

Never the less a productive morning.

I'd be interested in hearing how others are fixing the wear issue between butterfly shafts and base.

Garden hose and water cheapest fault finding tool I'll ever use or buy..... I would give this a go before you talk about what type of engine cam you have and if the floats in the crabs are set up correctly or if the needles and jets are right etc. It was a 10 minute diagnosis .... bit longer to fix ... but finding the problem is the challenge.

 

Carb starting fluid, propane (unlit) or even a cigar are excellent ways to find a vacuum leak without dousing the engine with water. Many mistakenly think carb throttle shafts are supposed to be air-tight - they aren't or they couldn't move...if they are TOO loose then re-bushing is the usual fix....this isn't a job for the amateur though.

If your carb was sucking air I would think the mixture would be lean....fixing the leaks may have enrichened the idle mixture even more... I'd be looking hard for incorrect parts bad needle/valve seat, sinking floats or float height/drop levels way off... Bear in mind these WCFBs HAVE to have the floats EXACTLY centered in those small float bowls. Sticking to, or rubbing against, the sides of the carb body will make things squirrley as hell..

Your running hot problem is probably unrelated to your carb issues (unless you are running REALLY lean). Could be cooling system, timing/vacuum advance, sticky T-stat or a host of other issues...also check your bottom radiator hose for collapsing...it should have a spring in it to prevent this and some aftermarket Bubba hoses do not.

 

This is an update to all who helped with advice on the 2x4 carbs on my 1960. Sorry to be late responding, but first illness then life got in the way. This weekend I finally got to the car and it appears the problem is 90% solved. I made a plywood block off plate for the front carb. Then I was able to remove the front carb and only deal with adjusting the rear. That worked great. In addition, I took the top off the rear carb and checked float levels and they seemed fine. I replaced the front carb and the car seems to run great. It has good response, no strong gas smell, plugs are burning a light brown color and gas mileage seems fine. I still have the issue of some fluttering when I stop at a light, but a slight blip of the throttle seems to solve the issue and it idles appropriately. I have yet to try the fix of putting in a tube to correct the cornering issue, but even that does not seem as bad as before.
I appreciate all the advice and support everyone has given me on this problem. This is a great resource.

 

if they are jetted for a 270 HP engine rejet to 245 HP specs. 270 carbs are jetted for open exhaust

 

I don't know that he ever said he had 270hp carbs but perhaps.

One other thing that may help is to run NGK-XR4 plugs....they are a slight heat range hotter than the ACR45S and what I run in my dual quad '61 and split window coupe...

 

FTF, checking the thermostat is my next job.

 

back in the day chevy supplied a stainless pieces to block the heat riser crossover in the intake manifold to make the 2X4 setup run better by reducing the exhaust heat to the aluminum intake manifold . they were in a package in the glove box of the corvettes. never saw them supplied with the full size cars.

 

My heat riser is blocked off ... I believe that is why you then need a crossover tube on the exhaust that runs infront of the sump pan

 

that is there to quiet the exhaust as blocking the heat riser crossover makes the exhaust louder. back in the day we used to used copper pennies hammered into the heat risers of flat head fords to make the dual exhaust louder

 

I was speaking to Bob Kunz (via email) seems like a great guy and very helpful as well. He put me on to Smith and Co. also a great bunch of people and extremely helpful with WCFB parts ... could not do enough for me ... quick email reply ... and above all excellent prices, spoke to Lana (via email), can't praise her can do attitude enough. Apparently Chuck gets new throttles arms for wcfbs made especially and that is where Bob gets his parts from. Tell you what, you guys have some great niche operators over in the US.

Lana Smith
Chuck Smith
Smith & Company
29081 Fruitvale Lane
Valley Center, CA 92082
760-749-5755

http://www.chucksmithandco.com

Fax 760-749-5355
olsmoothie@sbcglobal.net

 

Bob & Rob Kunz, and Ron & Tim at Daytona Parts are the only people that touch my carbs - although I've heard nothing but good about Chuck Smith's work as well...just haven't used his services myself..

 

What did you do to make the split exhaust manifold on that '53 Chevy louder? Most of them didn't need any help!

 

Frank, just stating that they get their replacement shafts from Smith and Co.