FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: emorrison96 on July 30, 2014, 11:19:27 AM
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Hey guys - I'm in the process of recreating a factory appearing 65 side oiler. I am using the bracket mounted fuel filter on the driver's head and have the pre-bent 3/8 fuel line that runs from the filter to the fuel pump inlet. I'm looking for a factory correct (at least in appearance) fuel pump. All of the fuel pumps I have seen except the Edelbrock appear to have 1/4NPT fittings and the hard lines and fuel filter canister have 3/8NPT. Does anybody know of a factory appearing fuel pump with the correct fitting size that will support 550-600 HP? Thanks in advance for your expertise.
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You are hard pressed with a mechanical pump of any type to support that kind of HP. Look at the ratings of your pump and also the size of the line. Generally you are looking at 8-an line of 1/2 tube to support that kind of HP in a electric pump running @ 20 PSI. Stock looking no way, mechanical, maybe with all new lines and a weld in sump in your tank. Or just go to a inline electric and be done with it.
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Thanks for the response. I've thought quite a bit about giving up on a mechanical fuel pump, but have so far talked myself out of it. If I remember correctly, wasn't the fuel pump on the SOHC a standard FE fuel pump with the arm modified? If so I would think one of those would do it. Just out of curiosity I wonder how much HP a pump from a SCJ would support, and which pump that was. Was it the same pump for a 65 R code Galaxie - that's the look I'm ultimately going for.
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I've used big mechanical pumps to support up to 700 HP, but they are not exactly stock appearing. I think you are correct that an SOHC style pump would get you there, but I really don't know which part number or type of pump that was. I'd guess it was a stock 427 pump with the different arm.
Regardless, if you are concerned about maintaining the stock appearance, what you could do is run an electric pump near the tank, and just feed the stock pump with the electric. I think that would allow you to maintain your line size and have plenty of fuel.
I don't know what the stock pumps came with in terms of fitting size; are you saying that you think they came with 3/8" pipe fittings? What size fittings are on your hard line? Are they pipe or inverted flare fittings? It wouldn't surprise me if the stock pumps used 1/4" pipe in the pump itself, and then a brass fitting to convert the pipe to 3/8" inverter flare.
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I agree with Jay that a mechanical can easily support 600hp. I believe the stock pumps are 1/4" pipe, not 3/8", and the stock feed line is 3/8" to the carb with flare fittings. But the problem is not the pump so much as it is the fittings. The inverted flare fittings have a drastically reduced hole size to accommodate the flare. That really reduces it's flow capability, so the stock stuff has it's limits regardless of what the pump can support. If you change those fittings to standard pipe fittings with a barbed end you can increase its flow capability because the hole size is not reduced near as much to support the flare. What I have done before is to take the stock 3/8" line and cut the ends off and use a very short piece of hose to connect the ends to a barbed fitting at the fuel pump and the fuel log or carb. It may not look 100% stock, but it isn't that noticeable and it flows MUCH better than the stock flared stuff. The Edelbrock is the only one I know of with 3/8" pipe fittings on the pump and it's rated up to 600hp, but even they will have a hard time supporting that claim using 3/8" flared fittings.
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The fittings on my hard lines are 3/8NPT, which have an external thread of 5/8-18 and look pretty large. The hard lines themselves are 3/8 OD tubing, which I believe has about a 1/4 ID. That should be at least 1/4 unimpeded flow...I think. The lines that I have are the same ones carried by summit racing for a 65 427 dual carb and they came with the pump to filter and filter to log lines. The filter has the same 3/8NPT as my hard lines. The reason I'm having so much difficulty is because of the 1/4 pipe vs. 3/8NPT vs. all of the other kinds and sizes of fittings there are. I have found a website that sells a pump with the part number C0AZ-9288-D (I believe the Cobras came with the C suffix) and it lists the pump as a "427 special" application. If my lines are stock, I would expect there not to be an issue *if* that part number is correct. After scouring Ebay there are many different versions listed in the titles, but it looks like they're all the same if you look at the specifications of them, and only the Edelbrock's list a 3/9NPT inlet and outlet. I'm thinking it might be worth it to go ahead and buy one of those "427 special" pumps and see what happens.
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I have always had to use a booster pump to run serious power or an Edelbrock mechanical or something. But your average replacement Delco or Motorcraft seems to starve after about 400 HP for me.
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OK, I have no idea how these things work, but I just replaced my stock pump with this one. My engine is a basically a 410 with headers, cam, edelbrock performer RPM, and 750 Edelbrock carb.
I replaced my 59 T-birds 5/16 fuel lines with 3/8, and put in this fuel pump just because it had the larger fittings than the 5/16 stock one. http://www.autozone.com/autozone/parts/Spectra-Premium-Fuel-Pump/1968-Ford-Galaxie-500/_/N-ir9kkZ8vcz2?itemIdentifier=302987_590495_0_
I don't know if it looks like your stock one. I also don't understand how it has pressure of 5.5psi to 7psi yet only pumps 40 gph. Then the Edelbrock is pressured at 5.5 to 6, and pumps 100+ gph?
Anyway. Don't know if any of this is relavent, but hey.
DAve J
Dave
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I go by first demand, .5 GPH per HP. Then I look at pressure if I am carbureted then 5 PSI is about right. Pumps are rated for a certain flow at their rated pressure and fuel line size, you can get more flow by increasing the line size usually on the return. You can also increase flow in the same size line by increasing pressure but then you will require a regulator at the carburetor inlet to prevent flowing past the seat and flooding. Usually you can download a chart that shows flow ratings per fuel line size and pressure.
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OK guys I have an update on this. I measured the fittings on my hard lines and they are 5/8-18 and not 3/8NPT as I previously stated. The fuel line in them is 3/8OD. These are supposed to be stock lines and if you go to summitracing and look at fuel lines for a 65 galaxie R code they sell these prebent. The fuel filter canister that I got from cobranda fits these fittings as shown. This fitting is very large! To date the only pumps I have seen are 1/4NPT, with the Edelbrock being 3/8NPT. Since the hard lines have straight cut threads and not the taper of NPT, even if the Edelbrock fit I haven't found a pump that has the internal flare to fit the hard line. If you're doing a factory restoration, where on earth would you get a fuel pump to fit these lines? I don't know if there was an adapter from the fuel pump to the line or not, but there was an adapter between the fuel line and the fuel log so maybe there was. Any ideas? Pulling what hair I have left out...
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That is a 3/8" inverter flare fitting, and you can certainly get an adapter fitting to adapter either the 1/4" pipe or 3/8" pipe threads in the fuel pump to that fitting. The factory Ford fuel pumps may have had that fitting size built in, but they may also have used an adapter. Here's one from McMaster Carr, but any NAPA store will have them:
http://www.mcmaster.com/#6432t114/=t4lfwg
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Ok tell me this,3/8 line from tank to pump and pump to fuel log but then why did they go to 5/16 from log to carbs? . On my 650 hp motor is the factory 3/8 line big enough and what about the 5/16 rubber from logs to carbs? restriction?
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Jay and someone else suggested running a electric pusher pump to supply the mechanical pump, I would be real Leary of doing that. I was always concerned about the diafram leaking and filling the crankcase full of fuel. I've never seen this happen but a friend did it and it cost him an engine and almost the rest of the car. I saw the after math it was pretty ugly. JMHO
Later Vick
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Ok tell me this,3/8 line from tank to pump and pump to fuel log but then why did they go to 5/16 from log to carbs? . On my 650 hp motor is the factory 3/8 line big enough and what about the 5/16 rubber from logs to carbs? restriction?
Is it a single 5/16" line to the carb? That makes no sense if the rest of the system is 3/8". However, if it is multiple lines to the carb(s), then each line will handle less fuel than the single line coming from the tank. How many lines are there to the carbs?
My opinion is that a 3/8" line is marginal for a 650 HP engine; 1/2" line would be a lot better.
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Jay and someone else suggested running a electric pusher pump to supply the mechanical pump, I would be real Leary of doing that. I was always concerned about the diafram leaking and filling the crankcase full of fuel. I've never seen this happen but a friend did it and it cost him an engine and almost the rest of the car. I saw the after math it was pretty ugly. JMHO
Later Vick
Yikes, that is an ugly scenario. I've never heard of that happening before...
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It was a real hot 327 in a Chevy II, when I saw it the next day from the fire wall forward was scorched. It blew the oil pan and both valve covers off. He said when it went off, at about 9,500rpm, it was one big flash and it blew it self out. That was enough that I never considered trying it.
Later Vick
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Even without an electric pump behind it, the gas that gets into an engine with a bad mechanical fuel pump will trash the rings and bearings quickly.
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This stuff is not that hard - but it does get confusing.
Fuel line size requirements are a function of both engine demand and pressure.
A larger fuel line is needed if less pressure is being used.
The line from a fuel tank to the inlet of a fuel pump is under a modest amount of vacuum - no pressure - thus it needs to be rather large in order to provide adequate flow. That's why even stock performance engines needed 3/8 lines, and race stuff needs 1/2" lines or larger/multiple feeds.
The line from the pump to the carb (or injectors) - any kind of pump - is under pressure. Depending on the pressure, the line can be smaller than the inlet side. On a single carb you are usually feeding a pair of needles & seats through .110" diameter orifices. Having humungous fuel lines to the carb on a street car might look cool, but its really kinda silly to be anything larger than 3/8ths.
Pipe threads (pipe threads are also known as NPT) are machined on a taper, and the dimensional description/conversion for them seems to have almost nothing to do with anything the normal guy will read on a ruler. The majority of automotive fuel stuff will have a 1/4 NPT thread, while a few race type items will have a far larger appearing 3/8 NPT thread. High pressure EFI pumps for under 500 HP will get by just fine with a spooky small 1/8 NPT thread on the outlet side - remember about the pressure/flow deal.
Most if not all aluminum casting fuel pumps will require an adapter to connect steel tubing lines. Its pretty much impossible to machine a inverted flare fitting into a casting on a production basis - so they use a female NPT thread. An inverted flare fitting is exactly that - designed with a central cone shape to seal against a flare at the end of a steel tube. The steel line will use a brass fitting with a straight thread, and the tube itself will have a 45 degree double taper. The taper seals against the cone machined into the aforementioned inverted flare fitting.
Your required - and very common - adapter thus ends up having a male pipe thread on one end and a female inverted flare at the other end. You can get a wide variety of combinations to fit most common line sizes to most common pipe threads - and even the factory performance pumps used them on many vehicles as well - not sure about your's in particular. I generally use the Carter M6905 here.