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Discussion Topic:
fuel pump rod
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41fatty |
04-16-2023 @ 7:11 AM
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Member
Posts: 95
Joined: Jul 2012
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after installing 2 good fuel pumps on my recent 85 hp flathead rebuild, i notice my fuel pump rod will not reach the full throw to pump fuel. the cam lobe is obviously different now. my fuel pump rod is the correct 8.87" for a 35-48 Ford. Is there a longer rod solution to this problem as i'm not about to remove the camshaftat this stage?
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kubes40 |
04-16-2023 @ 7:48 AM
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Senior
Posts: 3406
Joined: Oct 2009
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Place a piece of leather from an old belt in the cup of the fuel pump arm. Very old fix that works quite well. Of course, if the camshaft is worn badly (rare, but happens) well, then you need to replace the cam.
Mike "Kube" Kubarth
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41fatty |
04-16-2023 @ 8:55 AM
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Member
Posts: 95
Joined: Jul 2012
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Thank u Kube. At this stage removing the cam is not an option.
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41fatty |
04-16-2023 @ 12:44 PM
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Member
Posts: 95
Joined: Jul 2012
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I suspect 2 bad fuel pumps because when i manually cycle either one by hand and hook them to the fuel line I'm not pulling any fuel.
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37RAGTOPMAN |
04-16-2023 @ 12:47 PM
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Senior
Posts: 1962
Joined: Oct 2009
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fuel pump push rod, you need to measure the distance the rod goes up and down, if it does not have the correct stroke your cam is worn, you can use a electric pump , also are you using good parts for the rebuilding the fuel pump, stay away from foreign made parts sometimes ite better to use un worn original parts other then the diaphram. compare the new parts to the originals to see if they match up hope this helps 37RAGTOPMAN
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TomO |
04-16-2023 @ 6:57 PM
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Senior
Posts: 7256
Joined: Oct 2009
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Trying to pull fuel from the tank by cycling the fuel pump by hand usually doesn't work. A quick check of the fuel pump can be made by holding your thumb over the intake and operating the pump with your other hand. You should feel suction and when you stop pumping you should feel a slight pull on your skin for about a minute. The fuel pump stroke on a flathead V8 is slightly less than 1/4". The fuel pump stand gasket should be made of thin paper and under the baffle to give the most pump rod travel. It is unusual for the fuel pump lobe to be worn enough to fail to pump fuel. The most common causes are a leaking sediment bowl gasket, plugged fuel line, a collapsed flex line, a vacuum leak due to bad flex line, loose connections or using a rubber fuel hose with hose clamps in place of a flex line. To troubleshoot this problem I use a piece of steel fuel line with a fitting on on it and a vacuum gauge. I start by connecting the fuel line to the fuel pump inlet and crank the engine. After several stroke the gauge should read at least 10" of vacuum. If it does not reach that value, replace the sediment bowl gasket with a rubberized cork gasket and repeat the test. If your readings do not improve, the pump is probably bad. Next I connect the flex line and connect my piece of fuel line to it and repeat the test. You should get the same reading at as you got at the pump. If not, replace the flex line. Next disconnect the fuel line at the tank and blow compressed air through the line to make sure it is clear. If debris comes out, I recommend replacing the fuel line with a new copper coated steel line. If no debris comes out, I use another piece of fuel line with a fitting to connect to the fuel line and repeat the vacuum test to make sure that the connection to the flex line is good. The reading should be the same as at the fuel pump. If your pump will still not prime, blow through the fuel line into the tank to clear the tank pick up. If this solves the problem, check the inside of the tank for rust or other debris. Clean and coat thhe tank if necessary. This procedure saves time and money by not replacing good parts and knowing when you have found the problem.
Tom
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51woodie |
04-17-2023 @ 5:35 AM
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Senior
Posts: 517
Joined: Jan 2017
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TomO gave a good suggestion about checking inside the fuel tank. A previous owner of my '46 Coupe used red rubber gasket material for the fuel sender. The gasket was poorly shaped, and the excess that was exposed to gasoline inside the tank opening broke away, and pieces ended up in the bottom of the tank. I found this out when I removed the fuel sender, to check the float for leakage. I was lucky that no pieces had plugged the fuel intake pipe in the tank. I have no idea how fuel got into the aftermarket float, but that was the issue with the fuel gauge reading incorrectly.
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41fatty |
04-17-2023 @ 6:08 AM
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Member
Posts: 95
Joined: Jul 2012
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thank you, I will post my results.
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41fatty |
04-27-2023 @ 5:56 AM
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Member
Posts: 95
Joined: Jul 2012
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it helps to have the car level , otherwise you're fighting gravity. remove the spark plugs for a quicker crank. be patient and the fuel bowl eventually fills.
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