Weber 32/36 carb trouble!

[Spen]

I am racing a Ford Crossflow 1.3 engine in a Locost (poor mans
Caterham) race car with a 32/36 carb with a K&N 56-9070 filter. I am getting what I think is fuel starvation in hairpins and fast bends, effectively
engine stutters for about 1/2 – 3/4 sec. I don't think it's fuel surge in the tank. I have had the car on a very respected rolling road and the problem does not appear.

 

[kennypinkerton]

Fuel getting away from the main jet under hard G's? Maybe need a baffle in the fuel bowl?

I'm just throwing stuff out there - I have no clue what a 32/36 carb even looks like.

 

[DrEntropy]

It's a kinda "standard" looking downdraught device. Looks like a baby Holley. Primary/secondary setup. Very likely the "stagger" is as a result of side-forces in the bowl. I've not been involved with a racing car with this carb, perhaps there are Fiat racers with good answers. It was used on 2-litre T/C Fiats, IIRC. Went thru one on my friend/neighbor's 124 Spider a couple years ago.

 

[Matthew E. Herd]

Personally, I don't care for them. Had one on my midget when I got it, and it seemed fine, but nothing like the sidedraft webers!

 

[philman]

i have dual down draft webers on my tr7. I may have been experiencing a similar problem that seems to be fixed by using a 190 degree thermostat. (It was explained to me) Icing is sometimes a problem on down draft webers. I don't know the truth to that, but when I went to the higher temp thermostat I get better off idle response.

 

[swift6]

Finding a Formula Ford forum might offer the best tips and tricks for this particular problem. Afterall, that is the same carb they have to use on the 1600cc crossflows for the formula. I've not encountered the problem in my Cortina but it probably doesn't generate the same cornering loads that you do.

/ubbthreads/images/graemlins/cheers.gif

 

[AngliaGT]

Check the float levels,& if it has a diaphram,check that also.

- Doug

 

[Scott_Hower]

[ QUOTE ]
It's a kinda "standard" looking downdraught device. Looks like a baby Holley.

[/ QUOTE ]

I think Holley actually made them under license as the 5200.
My 2.0l Ford Capri (the German one, circa 69-78) had one. Nice little carb.

 

[DrEntropy]

I'll keep my side-suckers anyway. I'm kinda sure the DFV float is too low and side-loads cause the starvation. DCOE's don't do that. /ubbthreads/images/graemlins/wink.gif

 

[Scott_Hower]

[ QUOTE ]
I'll keep my side-suckers anyway. I'm kinda sure the DFV float is too low and side-loads cause the starvation. DCOE's don't do that. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

Agreed sir. But unless you've got a big boxabits and friends with a dyno, you'll go broke getting them tuned right /ubbthreads/images/graemlins/cryin.gif

 

[DrEntropy]

BAH!! twins on the Alfas & Loti and a single onna B... no problems. Been tweakin' 'em a looong time! They don't pass diesel fuel well so Diesela won't get 'em fitted. /ubbthreads/images/graemlins/grin.gif

 

[SteveL]

Sound like the float level to me, and I'm really really
familiar with them...

SteveL

 

[DrEntropy]

That's two Weber freaks voting "float level". /ubbthreads/images/graemlins/savewave.gif

 

[lesingepsycho]

My first inclination is not float level but rather fuel pressure. Are you running a fuel pressure regulator? From my experience, Webers are picky about fuel pressure. If I remember correctly, they want to have right around 3.5psi. Running the wrong fuel pressure can cause the problems you describe i.e. hard cornering and hard breaking cause stuttering or even stalling. I also used to have a '66 Mustang that had this problem very badly after I did a carb/manifold swap. So anyways, no amount of float tweaking will cure fuel pressure problems so I would check fuel pressure first before messing with the carb.

JACK

 

[DrEntropy]

Spen wrote:

[ QUOTE ]
I don't think it's fuel surge in the tank. I have had the car on a very respected rolling road and the problem does not appear.

[/ QUOTE ]

I'm stickin' with float level.

 

[SteveL]

[ QUOTE ]
My first inclination is not float level but rather fuel pressure. Are you running a fuel pressure regulator? From my experience, Webers are picky about fuel pressure.

JACK

[/ QUOTE ]

The 32/36 is not as finiky about fuel pressure as most Webers,
I've run 5 to 7 psi to mine, but I know for a fact that they
will stumble on sweepers... One thing you could try is a 90*
adapter from a '72 to '74 Capri 2.6L V6, unfortunately they raise the
carb about 1 1/2", plus you'll need to cobble the throttle
cable to work...

SteveL

 

[jessebogan]

The other possibility is fuel coming out of the bowl vents. IIRC this carb has openings in the top of the bowl that are open above the jet clusters, near the front of the bowl.These are inside the airhorn area, visible between the open choke blade and the front of the air horn. Hard cornering and a high float level could cause fuel to "splash" into the venturi area. Instant rich. I used to have a FF air horn, and it sealed this area off pretty well, and had a screened vent that was well below the adjacent air horn. As for what to do? The quickest solution that comes to mind would be to epoxy in some large diameter tubes that were higher. Less chance of actually getting raw gas into the carb that way. I also think a talk with some FF guys might provide some insight. Just a thought, good luck, Jesse