fuel overheating And Stock hood...
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Joined: Mar 2004
Posts: 420
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From: missouri
Car: 91 Camaro RS 383
Engine: carbed 383
Transmission: 700R4
Axle/Gears: 3.42 posi
fuel overheating And Stock hood...
It was about 80 yesterday and while in traffic my Car was running 200 just sitting there , then at 175 while driving. The car started dying and flooding itself out. It was so hot in the engine bay that the fuel was boiling and coming out the vent of the carb on my Holley 650 DP. I put my fiberglass L88 hood back on and it cured the problem. ANYONE ever hear of this happening??
yep
Very common this time of year with a carburated car. Especially if you are running pump gas and the gas stations have not changed over yet from their winter time (anti freeze) gas. When it starts getting warmer that anti freeze stuff vapor locks very easy, I was experiencing this back in mid March already.
I believe the norm for the gas stations to change to summer grade fuel is sometime towards the end of April.
There are also other things you can do to prevent the gas from getting too hot. One thing that I like to do is install a return line to the gas tank. Make it as close to the carb as you can, this way the fuel is always circulating through the fuel line even when idling and your needle and seats are closed. This keeps the fuel cooler as it does not sit stagnant in the fuel line soaking up heat.
This trick has worked for me everytime, actually this was factory on carburated cars from GM starting around 1970.
It is not as much of an issue with fuel injection since they have so much fuel pressure. There are someother things to prevent vapor lock also, one is to run higher octane fuel as it does not ignite as quickly as the cheaper pump gas, I have noticed that 89 octane vapor locks much quicker than Sunoco 94 (which is what I run) and if you want to spend some more money, mix it with race gas (110 octane) you won't have any problems with that stuff vapor locking.
If you run a mechanical pump on your car it will be more sensative to heat, an electric pump has less of a chance to vapor lock. But as I said, keep all your lines away from any source of heat, a return line will work wonders for you, although you don't want to return too much fuel to the tank, you will have trouble holding fuel pressure. What I do is install a "T" fitting in the line close to the carb. The part of the "T" that will be the return I solder that up solid and drill a .060 hole in it so that is just trickles fuel back to the tank, then dial in your fuel pressure with your adjustable regulator (if you have one) and the return line only needs to be 1/4 inch line, nothing major. And have the line dump back into the tank, I usually drop the tank, remove the sending unit and solder a new line into the top of the sending unit, unless you have a line you are not using at the sending unit then this part will not be necessary. This little trick has worked for me for years. Hope that helps, Larry.
I believe the norm for the gas stations to change to summer grade fuel is sometime towards the end of April.
There are also other things you can do to prevent the gas from getting too hot. One thing that I like to do is install a return line to the gas tank. Make it as close to the carb as you can, this way the fuel is always circulating through the fuel line even when idling and your needle and seats are closed. This keeps the fuel cooler as it does not sit stagnant in the fuel line soaking up heat.
This trick has worked for me everytime, actually this was factory on carburated cars from GM starting around 1970.
It is not as much of an issue with fuel injection since they have so much fuel pressure. There are someother things to prevent vapor lock also, one is to run higher octane fuel as it does not ignite as quickly as the cheaper pump gas, I have noticed that 89 octane vapor locks much quicker than Sunoco 94 (which is what I run) and if you want to spend some more money, mix it with race gas (110 octane) you won't have any problems with that stuff vapor locking.
If you run a mechanical pump on your car it will be more sensative to heat, an electric pump has less of a chance to vapor lock. But as I said, keep all your lines away from any source of heat, a return line will work wonders for you, although you don't want to return too much fuel to the tank, you will have trouble holding fuel pressure. What I do is install a "T" fitting in the line close to the carb. The part of the "T" that will be the return I solder that up solid and drill a .060 hole in it so that is just trickles fuel back to the tank, then dial in your fuel pressure with your adjustable regulator (if you have one) and the return line only needs to be 1/4 inch line, nothing major. And have the line dump back into the tank, I usually drop the tank, remove the sending unit and solder a new line into the top of the sending unit, unless you have a line you are not using at the sending unit then this part will not be necessary. This little trick has worked for me for years. Hope that helps, Larry.
Thread Starter
Member

Joined: Mar 2004
Posts: 420
Likes: 0
From: missouri
Car: 91 Camaro RS 383
Engine: carbed 383
Transmission: 700R4
Axle/Gears: 3.42 posi
Thanks for all the advice. The car is still doing it during the heat of the day, but once the sun goes down its better. My Car like I said has Holley on it and the fuel lines have to run across the motor so I'm sure that is where it picks up all the heat from. I ran this same setup last summer with no problems so its just funny that it's happening now. The car does have an electric fuel pump and I run 93 octane in it because of the compression ratio. I also had a 9"x3" air cleaner on there because of hood clearance so this weekend when i get the bigger air cleaner that may help let some air into the carb to help it out.
Thanks
Thanks
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