edelbrock 650 boiling fuel 383 big block

[Dennis H]

Due to advice from themechanic, I have an air-cleaner lid like Ron's. Have not had a chance to really put it to the test yet. That will come in August/Reno. My Speed shop tech says some are actually put a switch operated fan under the hood - like a 3 inch oscillator. Just to keep air moving under extreme conditions. I'm considering it.

 

[Meep-Meep]

It's the reid vapor pressure of today's fuel that is screwing us up so whatever you can do to keep the carb cool is a benefit.

 

[ckessel]

Another thing to add to the fuel disscussion is the changes to the fuel with regards to ambient temperatures. Gas is modified for cold to hot temps. If you picked up fuel at the local station when the temps have been cold and suddenly it gets hot, like out here on the left coast, this can cause the fuel to boil. When I worked at a speedshop back in the early 80's we sold alot of carb heat shields made by GM for Vette applications that worked extremely well. They were just a gasket, heat shield, gasket arrangment that didn't have vacume leak issues like the multiple plate/gasket ones that get over like 1/2" in stackup. GM of course discontinued them but you might be able to get them from a resto supplier. They were made in standard flange and spreadbore styles so you should be covered for either direction. They also had the firing order stamped in them which is the same for us. I used them on my Duster and Challenger and said goodbye to the fuel boiling. I'm curious to see how they would work with the newer fuels that have been spiked with alchohol or the E85 that some use.

 

[Dennis H]

Another thing to add to the fuel disscussion is the changes to the fuel with regards to ambient temperatures. Gas is modified for cold to hot temps. If you picked up fuel at the local station when the temps have been cold and suddenly it gets hot, like out here on the left coast, this can cause the fuel to boil. When I worked at a speedshop back in the early 80's we sold alot of carb heat shields made by GM for Vette applications that worked extremely well. They were just a gasket, heat shield, gasket arrangment that didn't have vacume leak issues like the multiple plate/gasket ones that get over like 1/2" in stackup. GM of course discontinued them but you might be able to get them from a resto supplier. They were made in standard flange and spreadbore styles so you should be covered for either direction. They also had the firing order stamped in them which is the same for us. I used them on my Duster and Challenger and said goodbye to the fuel boiling. I'm curious to see how they would work with the newer fuels that have been spiked with alchohol or the E85 that some use.

Have a picure?

 

[petieg383]

I had the same problem with my 70 GTX 440. Solved the problem with a CoolCarb plate workes greatView attachment 257850

I saw those guys at Carlisle. I'm glad to hear a good review. I think I might pick one up.

My 70 Roadtrunner has a Weiand intake on my 440 with a 750 Holley and the air grabber hood. I'm hoping it fits.

When I had an Edelbrock carb on there with the 3/8" Edelbrock spacer, it pushed open the Air Grabber hood a tiny bit. Before I put the Edelbrock spacer on there, you could hear the fuel bubbling when you shut the car off. After the spacer, it didn't do it at all.

 

[ckessel]

No picture, but looks like the one on 383man and gtxguy's cars. I was always going round and round with the owner of the speed shop, gm lover, trading puns about using a gm part on a mopar. Miss those times.

 

[superbeedave]

Let's just say it is the nature of the Beast. The old Carters had a vent that let fumes escape into the atmosphere and of course out of the carb. and the gas back then didn't heat up as much also. The Edelbrock design does not have a vent so when ever your engine gets hot after running for awhile then shutting it off and the gas sits in the bowls and heats up more the gas will rise in the channels when it rises high enough it will eventually start dripping out the nozzles. It doesn't come out the power valve nozzles because the weight and ball keeps the gas from escaping thru. I know from experience that after a good long hot run in the summer and after shutting off the car within a few minutes you will smell raw fuel coming from under the hood. That is a clear indication that the fuel is dripping out the nozzles and into the intake. So we all try everything we can to keep the carb. cooler but in reality the aluminum of the carb. will heat up to a point where the gas will hit it's boiling point and start to rise when it sits within a few mins. I have a Carter 625 carb. from 97 that I used for a long time and I had to use it last year and it never ever did any of this like my Edelbrock avs 650 did. As long as you do not get vapor lock you will always have to deal with this a lot or a little depending on what steps you make to keep the carb. cooler! Thank you, Dave

 

[Dennis H]

Right. The spacer, wrapping and moving lines, and other measures reduce the severity but will not completely solve the problem. Electric fuel pump helps little if at all for mine.

 

[383man]

Let's just say it is the nature of the Beast. The old Carters had a vent that let fumes escape into the atmosphere and of course out of the carb. and the gas back then didn't heat up as much also. The Edelbrock design does not have a vent so when ever your engine gets hot after running for awhile then shutting it off and the gas sits in the bowls and heats up more the gas will rise in the channels when it rises high enough it will eventually start dripping out the nozzles. It doesn't come out the power valve nozzles because the weight and ball keeps the gas from escaping thru. I know from experience that after a good long hot run in the summer and after shutting off the car within a few minutes you will smell raw fuel coming from under the hood. That is a clear indication that the fuel is dripping out the nozzles and into the intake. So we all try everything we can to keep the carb. cooler but in reality the aluminum of the carb. will heat up to a point where the gas will hit it's boiling point and start to rise when it sits within a few mins. I have a Carter 625 carb. from 97 that I used for a long time and I had to use it last year and it never ever did any of this like my Edelbrock avs 650 did. As long as you do not get vapor lock you will always have to deal with this a lot or a little depending on what steps you make to keep the carb. cooler! Thank you, Dave

Actually they have to be vented at atmosphere or a carb wont work. But the Eddy's may not have an external vent is what you are saying as I have not used one so I would have to see one. But they all have the internal bowl vents that vent to the airhorn. When they have the external vent it will open at idle and vent the bowl and then when you step on the gas the external vent will close and vent the carb to the internal airhorn vents. Thats basically what they call a balanced carb as airhorn pressre can be a bit less the atmosphere pressure. But when hot it will vent out the internal airhorn vent which will vent fumes right into the eng and make it seem rich on hot starts. Ron

 

[superbeedave]

Actually they have to be vented at atmosphere or a carb wont work. But the Eddy's may not have an external vent is what you are saying as I have not used one so I would have to see one. But they all have the internal bowl vents that vent to the airhorn. When they have the external vent it will open at idle and vent the bowl and then when you step on the gas the external vent will close and vent the carb to the internal airhorn vents. Thats basically what they call a balanced carb as airhorn pressre can be a bit less the atmosphere pressure. But when hot it will vent out the internal airhorn vent which will vent fumes right into the eng and make it seem rich on hot starts. Ron

Thanks for clearing that up a little better for me Ron!

 

[UKPlymouth]

I had that issue with iron intake and Edelbrock carb. My Holley rectified the problem.
I then went further as I was tuning and now have an Air Gap and one of the new 750 Street Demons with phenolic fuel,bowl. No problems now and it a decent carb too.

 

[383man]

Thanks for clearing that up a little better for me Ron!

No problem as you were basically right but it can get confusing as some carbs have external bowl vents and some do not. Ron

 

[shovelluv]

Well... problem solved everyone. I took the intake off and replaced my valley pan with Fel pro 1214. It has the heat riser ports blocked off so the exhaust gases will not enter the intake. I also flipped the intake over and loosely packed the heat riser ports with ceramic wool. Now, after a hour of driving, under the carb is the coolest part of my intake. Yes, I am running a electric choke.

 

[D575]

So , Is there anything that can be added to the fuel to raise the Boiling point ? 110 leaded ? kerosene, octane booster ?

 

[Dennis H]

I've been adding Amsoil 100:1 Marine on occasion. Won't get a real world test til Reno at 107 degrees and 5000 feet extended idling. I will report. Only other thing to do is extend the clearance of the hood insulation to allow the open air filter top recommended by themechanic to breathe better.

Extended heat soak in real conditions will be the test. Let it set an hour and see how it re-starts and runs. These dirty bastards with the ethanol thing are trying to force us all to fuel injection. I won't go.

 

[mentor70]

So , Is there anything that can be added to the fuel to raise the Boiling point ? 110 leaded ? kerosene, octane booster ?

http://race-gas.com/

 

[TxDon]

I found this thread on a search, thanks to the OP. I have been having this same problem with my car which has a 750 Edelbrock carb on a Mopar Wedge intake. When I run the A/C in our current 95-100 degree weather I get fuel smell after shutdown and if I restart while still hot I have to put my foot to the floor like its flooded for it to start. I can live with this for now but my concern is the raw fuel dumping into the motor. How much gas is actually going in and could that cause oil dilution issues?