| village grande | -- 10-05-2019 @ 6:17 PM |
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I have a 1951 ford stock 8BA V8 i would like to install a ( power valve block off plug ) in my Holly 94 carburetor to determine if this is the source of my leak down problem. What can I expect as far as performance with no power valve. I will attempt to upload the picture of the plug from Advanced Auto
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| TomO | -- 10-07-2019 @ 10:13 AM |
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Your leak-down problem is most likely the power valve gasket, not the power valve itself. Without the power valve your performance would suffer significantly. You can do a quick check on the valve by sucking on the end that does not go into the carb. If the valve moves it probably is not leaking. The power valve is closed under high vacuum conditions and opens under low vacuum (wide open throttle) conditions to enrich the mixture when the engine is under load. I use the gasket with the triangular cutout. I hand tighten it and thenturn it an additional 1/6th turn. Then I fill the bowl with just enough fuel to cover the top of the power valve and let it sit for 12 hours or more. The fuel should not be below the top of the power valve, if it is I tighten the power valve another 1/6th of a turn and repeat the test. If the gasket is leaking, it will be wet. Tom
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| village grande | -- 10-07-2019 @ 5:37 PM |
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tomo appreciate the reply, I'm aware of the problems with leaking power valves and purchased this one from Daytona parts with the machined gasket surface. plunger moves when i suck on it but i'm losing 1/4 inch of gas overnight and there's no sign of wetness on underside of valve or gasket. I will continue to observe level to see how far it goes down. it's now just to the top of the plunger. I'll report back tomorrow. My experience has been after a few days in car bowl is empty and car won't start. I know this is not due to evaporation
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| ken ct. | -- 10-07-2019 @ 9:52 PM |
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Could you possibly have a pin hole in the bowl itself. Plus I always apply lite lock tite to the 2 brass drain plugs at the front of bowl. ken ct
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| mfirth | -- 10-08-2019 @ 4:51 AM |
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Does the 1/4 inch loss in the bowl occur on a hot or cold engine? This poor excuse for gas will evaoprate to a degree, specially with a warm engine. my 2 cents mike
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| village grande | -- 10-08-2019 @ 9:54 AM |
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I have installed new gaskets on the two brass drain plugs and applied s small amount of sealant to the threads. The carburetor is off the car and sitting on the workbench so I can observe the fuel level in the bowl. As of this morning the level seems to be holding just a fraction above the top of the power valve plunger. Is there an internal path for the fuel to travel that would allow it to settle at its present position? Maybe this is the correct level? I do have it covered to minimize evaporation and also have a separate plastic container with gas in it to use as a comparison for evaporation. At present I see no sign of fuel at P/V gasket or P/V itself. I'll give an update later today.
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