2X4 carbs too hot???

[Robert Willis]

Re: 2X4 carbs too hot???

I have a set of 1st design WCFBs on my 57 and have no problems like this . I also rebuilt a set for a friends 58 and there are no problems with his as well. Maybe a good carb man is in order. BOB

http://members.kos.net/willisb/vette.html

[Robert Willis]

Re: 2X4 carbs too hot???

I have a set of 1st design WCFBs on my 57 and have no problems like this . I also rebuilt a set for a friends 58 and there are no problems with his as well. Maybe a good carb man is in order. BOB

http://members.kos.net/willisb/vette.html

[John H.]

Re: 2X4 carbs too hot???

When I restored my '57 nearly five years ago, I sent the (original) WCFB's to Bob Kunz for rebuild, as they had been badly rebuilt by several Bubbas during its lifetime with wrong jets, rods, etc. and were a mess. Got them back rebuilt to original metering specs, bolted them on with double gaskets, used a new heat riser valve, and the car has run flawlessly ever since (aside from occasional fiddling with idle speed, which is the nature of the beast). Idle mixture screws on both were within 1/8-turn of "on the money" right out of Bob's box, all I had to do was tweak the idle speed screw a bit when I fired it up the first time. I run 45-46 heat range equivalent plugs and change them once a year; anything colder and you'll foul them constantly - also nature of the 2x4 beast. A really good carb man can really simplify your life

[John H.]

Re: 2X4 carbs too hot???

When I restored my '57 nearly five years ago, I sent the (original) WCFB's to Bob Kunz for rebuild, as they had been badly rebuilt by several Bubbas during its lifetime with wrong jets, rods, etc. and were a mess. Got them back rebuilt to original metering specs, bolted them on with double gaskets, used a new heat riser valve, and the car has run flawlessly ever since (aside from occasional fiddling with idle speed, which is the nature of the beast). Idle mixture screws on both were within 1/8-turn of "on the money" right out of Bob's box, all I had to do was tweak the idle speed screw a bit when I fired it up the first time. I run 45-46 heat range equivalent plugs and change them once a year; anything colder and you'll foul them constantly - also nature of the 2x4 beast. A really good carb man can really simplify your life

[Bob R.]

Re: 2X4 carbs too hot???

Just a quick thought. Are all of the spacers properly in place between the base of the carb. and the manifold. My 63 has a metal plate a plastic spacer and a gasket. The purpose is to prevent heat from the base of the carb. Are all these in place.

[Bob R.]

Re: 2X4 carbs too hot???

Just a quick thought. Are all of the spacers properly in place between the base of the carb. and the manifold. My 63 has a metal plate a plastic spacer and a gasket. The purpose is to prevent heat from the base of the carb. Are all these in place.

[Steve Junkersfeld]

Re: 2X4 carbs too hot???

Don, Here's my two cents. I have built two sets of 2x4s. One was a mixture of odd-ball WCFBs and 57 manifold - which went on a 327. The other is a correct setup for my 56 Corvette. Both took a little time to get right - but both are very very driveable. I've found the WCFB to be real sensitive to float level - too low and it will cut out on turns and hard acceleration - too high and it will flood in a heartbeat. I have thought about blocking off the crossover in my Corvette only as a measure to keep the manifold nice - I did remove the flat "flapper" plate from the heat riser. The 327 has a functioning heat riser and an open crossover. My vote - keep playing with them and don't accept poor performance just because "That's the nature of the 2X4 beast". If carbs aren't your forte - I agree with some of the other folks - get a good carb man. Steve

[Steve Junkersfeld]

Re: 2X4 carbs too hot???

Don, Here's my two cents. I have built two sets of 2x4s. One was a mixture of odd-ball WCFBs and 57 manifold - which went on a 327. The other is a correct setup for my 56 Corvette. Both took a little time to get right - but both are very very driveable. I've found the WCFB to be real sensitive to float level - too low and it will cut out on turns and hard acceleration - too high and it will flood in a heartbeat. I have thought about blocking off the crossover in my Corvette only as a measure to keep the manifold nice - I did remove the flat "flapper" plate from the heat riser. The 327 has a functioning heat riser and an open crossover. My vote - keep playing with them and don't accept poor performance just because "That's the nature of the 2X4 beast". If carbs aren't your forte - I agree with some of the other folks - get a good carb man. Steve

[G B.]

I would check the choke heat tube.

Sometimes the metal tube inside the passenger exhaust manifold cracks or rusts through. This allows the rear carb to suck pure exhaust gas into its body though the choke heat tube rather than heated ambient air.

[G B.]

I would check the choke heat tube.

Sometimes the metal tube inside the passenger exhaust manifold cracks or rusts through. This allows the rear carb to suck pure exhaust gas into its body though the choke heat tube rather than heated ambient air.

[Clem Z.]

Re: Disagree on the vapor pressure issue.

gm had to move the fuel injection return line from the engine compartment to the fuel tank on the 99 C-5s because the heat from the engine was causing fuel to get hot and causing vapor emission problems. you can hear the fuel boiling in some of these carbs with aluminum manifolds when you shut off the engine. chrysler tried even the thermoquad with a resin main body to cut down on the fuel boiling away.

[Clem Z.]

Re: Disagree on the vapor pressure issue.

gm had to move the fuel injection return line from the engine compartment to the fuel tank on the 99 C-5s because the heat from the engine was causing fuel to get hot and causing vapor emission problems. you can hear the fuel boiling in some of these carbs with aluminum manifolds when you shut off the engine. chrysler tried even the thermoquad with a resin main body to cut down on the fuel boiling away.

[Duke W.]

Re: 2X4 carbs too hot???

You must have a 300 HP engine. The 340 doesn't have the phenolic insulator or heat shield, but the heat riser passage is closed - just a passage under the plenum. I've never had a problem with vapor lock.

The AFBs have a bimetallic valve between the secondaries known as a hot idle compensator. It's supposed to open to admit more air when it gets hot enough to boil fuel out of the bowls and keep the mixture from getting too rich.

Duke

[Duke W.]

Re: 2X4 carbs too hot???

You must have a 300 HP engine. The 340 doesn't have the phenolic insulator or heat shield, but the heat riser passage is closed - just a passage under the plenum. I've never had a problem with vapor lock.

The AFBs have a bimetallic valve between the secondaries known as a hot idle compensator. It's supposed to open to admit more air when it gets hot enough to boil fuel out of the bowls and keep the mixture from getting too rich.

Duke

[don whitehead]

Re: 2X4 carbs too hot???

I do not have to remove the manifold? Above or below the gasket? Thanks, Don