Hi everyone. Need some advice how to keep my intake manifold a bit cooler. Currently I have 53 4 door bel air,that I just finally got it registered. One evening finally drove the car, total of 12 miles from my parents to my new home. Before leaving I added 20 bucks on gas then took my first trip. Living in Las Vegas summer weather is 105* and the car handles pretty well waiting on the light never went pass 210* . As I was getting closer to home the car felt like running out of gas when attempting to accelerate. Right when I hit my curb it dies. I noticed that I was out of fuel when raising the hood. Also i can hear gurgling by my carburetor. I go ahead get a gallon of gas and begin to pour into the tank and little down the carburetor. Right when the fuel make contact to the carburetor it begins to boil. I currently have 235 with Weber 32/36 from Langdons and exhaust manifold is still the original. Although the exhaust was modified by previous owner to be a split exhaust. What are some ideas to keep the intake a bit cooler?
Be sure the heat riser flap is working in the manifold, it could be missing and you are getting direct exhaust heat right at the base of the carburetor. The split exhaust could also be a problem, it may be blocking flow more then helping creating excess heat. Did you install the spacer(s) under the carburetors?
Only spacer I have added was the adapter plate that came with the carburetor. I'll check the flapper, I did notice the stem to turn the flapper has been grinded off.
Residual heat, poor quality fuel, lack of phenolic block under carb, & gutted heat riser are all fighting you. A 1/2'' thick insulator under the carb helps, and an electric pump in the rear with a switch … Maybe show us the set-up with a picture - always a help.
Pics help The heat riser needs to work You need the phenolic spacer between the carbs and intake Having the fuel lines away from heat helps Electric pump can help
Make sure ignition timing is straight all the way out to cruise RPM, retarded timing will run hot and waste lots of fuel.
If you can add a small return line off the gas line near the carb, going back to the tank it will help. Some later model carburetor cars had this to fight vapor lock. Some Japanese cars had a fuel filter with the extra line coming off, this is the easy way to add a line. Sorry I don't remember exactly which model but some late 70s toyotas or datsuns. Wrapping the fuel line with insulation inside the engine compartment will help too. In severe heat you can pour water over it for instant cooling. Your Chev never had this much trouble when new because today's fuel is formulated for fuel injection which is always under 35 pounds of pressure so it can't vapor lock. So, another thing you can do is add some kerosene or diesel to lower the boiling point of the fuel. This also lowers the octane so not recommended if your compression ratio is over 7 to 1. If you have stock low compression you can add up to 10% kerosene stove oil or diesel. Kero or stove oil are better, diesel can give your exhaust a slight diesel odor but diesel is always available.
I have uploaded photos what I had on my phone will take better pics today, right when getting ready to tinker with it got called in.
Not necessarily. One of the usual recommended solutions to keep vapor lock at bay is wrapping the fuel line from the pump to the carb with insulation. Wood is a decent insulator, so theoretically wooden clothes pins, clamped one right next to the other along the entire length of said fuel line, should provide some insulation from engine heat. I'd never do it, but it does add credibility to the suggestion of using clothes pins to cure vapor lock. Someone in the past has probably had some limited success with this approach. Of course it would look like ass.......
302 gmc nailed it you are vapor locking from all the crap not being right. The electric fuel pump will solve the vapor lock but you need to do the other things also. Good luck
You've gotten the correct advice from a number of guys here. You have got to put that insulator under your carb. Heat to the base of the carb is also needed. You're now running a 2 barrel? All that air flowing into the stock one barrel intake must freezing the base of your carb and causing the vapor lock.
If you change to Fenton style exhaust manifolds, it will take the direct heat off the intake. Many add a steel plate to the bottom of the intake then route 2 copper tubes to the plate and the Fentons to give "some" heat and drivability to your engine which you will only need in the in winter months living in Las Vegas. I would try the Fentons first without the plate. A phenolic or wood spacer is very very good advice as I use them on all exhaust heated intakes.
Add a real mechanical fan if you don't have one, the small electric on the front is not adequate. The extra air from a mechanical fan may be just enough to keep the carb and fuel lines cool.
Thanks everyone for the help. I'll be looking into my exhaust for heat riser. Also I've been around town for a carb spacer and no luck. Shops only carry 4 barrel. So this weekend I'll be making my own out of wood
I have installed a couple of these "Thermal blocks" on Weber 32/36. I sourced them here: https://www.ipdusa.com/products/8433/100848-thermal-block-for-weber-dgv-carburetor-5-inch-thick They are 1/2" thick and one end is wider than the other. A store that specializes in VW and dune buggy parts might have this in stock. I marked mine "PRI" and "SEC" to avoid (well miminize...) assembly errors. Also longer studs (1.5") are needed. I bought mine off the wall at O'Reilly. Google gives me an Edelbrock number of 8008.
Marine Plywood spacer really helps with the fuel boil you are experiencing. !/2 inch thick. I had a 57 312 Ford that did it every time it was over 90 degrees and I was in slow traffic. Small low pressure electric fuel pump will help.
So the heat riser valve has been removed. Will be looking for the stock fan, when I bought the car it did not come with the metal fan so reason I added the electric. Will look into adding electric fuel pump after adding the thermal spacer see if it helps
Your on the right track See if you can find a stock manifold with the riser still in place Or maybe now the time for a set of Fenton’s
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