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  #1  
Old 08-15-2006, 07:15 PM
451Mopar 451Mopar is offline
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Post Fuel additive question?

OK, It seems these new formulations of pump gas are vaporizing way too fast and easy. Is there any fuel additives that will help?

I seem to be having two problems here.

If I shut down the car on a really hot day and it sits a day or two, the carb fuel bowl is empty. This is a pain because I am using a mechanical fuel pump, and it takes alot of cranking to re-fill the fuel bowl for the engine to start.

The second problem, again on hot days when the engine is running hotter than normal, is I get a bit of smoke out the exhaust when I re-start the car.

The smoke problem I believe is from the fuel boiling in the carb, and giving a extra rich mixture on startup. This only happens after driving in hot weather, then stopping at a store, then come out a little later and re-start the engine.

I thought I may be getting extra oil in the cylinder, when the engine sits when it is hot, but I haven't noticed any extra oil being used, and the spark plugs look fine. I also don't think the smoke is coolant because the radiator is still full. I do think it has to do with the fuel and temperature of the carburator.

Anyhow, just wanted to know if there was an additive that would help, otherwise, I may add an intake to carb spacer and see if I can get some of the heat away from the carb.
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Old 08-15-2006, 08:19 PM
The_Dakota_Kid The_Dakota_Kid is offline
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Yea cheap gas is here to stay, all the fuel additives arent worth the money IMO. At the soaring price of high test, then adding extra money to gas additives still wont cause the hard starting even with additives and race gas. I will suggest blocking the heat cross over in the intake. Also make sure you have a thick factory style carb gasket to insulate heat. Maybe considering a wood, or compisite style spacer? The single thing to do to help the hard starting is a electric fuel pump.
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Old 08-15-2006, 08:27 PM
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ehostler ehostler is offline
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Maybe it's an altitude thing. Down here, I don't have that problem (when the car is working). I have the heat cross overs in my weiand intake, Speed Demon 750, and factory style mechanicle fuel pump.
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Old 08-16-2006, 04:59 AM
TK TK is offline
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If it fits, a plastic spacer seems to fix it, unless your check valve is sticking in the pump, but it still shouldn't drain the carb.
I run a spacer, to fix my boil over problems, and i live in Alaska, 200 feet above sea level.
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Old 08-16-2006, 05:56 PM
Mean Gene Mean Gene is offline
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I don't have a prob either, I have the Weiand too. Holley 750, factory mech. fuel pump and phenolic (sp?) spacer. Fires instantly everytime.
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Old 08-16-2006, 06:35 PM
gomopar gomopar is offline
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If you have a Holley, you can consider, in addition to phenolic spacer, use an aluminum heatshield witch extends under fuel bows and blocks down radiant heat from intake.
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Old 08-16-2006, 06:58 PM
451Mopar 451Mopar is offline
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This is actually my 360 with an Edelbrock Performer intake, and Edelbrock 650 cfm AFB style carb.
I'm in Denver, Mile high altitude, and they formulate the gas slightly different here for the higher altitude, not to mention all the octane ratings are a few points lower than the fuel sold at lower altitude. Normal pump gas is only 85 octane, and premimum is 91 octane here.

I think blocking the heat crossover would work, but I drive this year round, so I don't want to block the crossover since winter is comming pretty soon.
A Phenolic spacer is probbably the best place to start, but the intake is a spread bore design and the carb is the square design, so maybe I can find a spacer that converts the mounting difference. Rignt now, I'm just using the cheap plate Edelbrock sells to convert the patterns.
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Old 08-16-2006, 09:21 PM
gomopar gomopar is offline
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Okay. That high altitude fuel stuff and tuning is all new to me, since I live relatively close to sea level and around here we don,t practically have places higer than church tower (hah). Though we have long, dark, and cold winter and lot of experience how to survive with sub zero temperatures.

Try find a phenolic or fabricate one from thick nylon. Blocking heat crossover can cause cold running problems. After a somewhat long driving period, engine will likely to stall, and once warmed, idle tends to go too high. Not good. At least you should have intake air pre heater thermostat in function inside airfilter.

Fuel line bypass from between fuel pump an carburetor to fuel tank may help for a hot day short stop fuel flooding. As fuel boils inside a carb needle and seat assembly could pass more fuel to the fuel bowl because of remaining pressure between pump and carb. Fuel line will also pick up engine heat and fuel will expand even further. Bypass line should have orifice no larger than .030" or even smaller, otherwise it will eat out your pump capacity. Just bleed pressure out.
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Old 08-17-2006, 02:24 PM
451Mopar 451Mopar is offline
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Thanks, I am using the vapor return fuel filter, and I really don't had any vapor lock problems, just the little puff of smoke on startup, and sometimes no fuel in the bowl. The weather has been a bit cooler lately (less than 90's) and it seems OK now. I think one problem I may have, is my radiator is marginal at best. When I'm having these problems the engine temp is above "nornal". I say normal because I just have the stock dash gauge.
The Thermostat temp is 180, and I know pretty well where that is on the gauge from driving in moderate weather. When I'm having these problems, the gauge needle is a above the normal area, so I figure I'm around 200+ degrees?
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Old 08-17-2006, 02:46 PM
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pishta pishta is offline
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Get yourself a 3/4 inch block of hardwood and go to town with a holesaw and a sander. Make a duplicate of the Edelbrock convertor plate and install it. Wood makes a great heat block, Aluminum doesnt. They make frying pans out of it for a few reasons, Heat convection is one of them.
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Old 08-17-2006, 04:41 PM
flipper35 flipper35 is offline
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Make sure the bowl in your AFB hasn't cracked also.
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Old 08-17-2006, 05:03 PM
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pishta pishta is offline
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Quote:
Originally Posted by flipper35
Make sure the bowl in your AFB hasn't cracked also.
Que? Hard to crack an integral cast bowl, but I suppose it could happen. Most of my AFB's percolated after a run too, its the heat and the material. I always put an electric pump on mine too. Itll pump right through a mechanical to fill those bowls, and itll keep the mechanical "in" the fuel too.
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Old 08-17-2006, 05:37 PM
flipper35 flipper35 is offline
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Shouldn't happen, but it has and does in the older designs. Edelbrock seems to have the problem licked as of a while ago. This was onthe Weber based AFB.

My Carter used to have the same problem you all are having. Different carb now, the 625 was too little.
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