Fuel pump fitting

[OldRedFord]

What size is the thread on the fuel pump fitting? Its a mechanical pump.

I honestly do not know. Never had to plumb fuel lines before.

[BobbyFord]

Try this: http://www.performancesst.com/docs/meas ... hreads.pdf

[Dragon]

1/4 npt

[OldRedFord]

Try this: http://www.performancesst.com/docs/meas ... hreads.pdf

I went by that and measured 1/2". Went down to NAPA and got a 1/4 SAE line. Too small. I have a 9/16 SAE standard flare fitting and it is a hair too big. So I am thinking it is a 1/2" SAE flair fitting I need on that end?

I went back to NAPA with the chrome fuel line for the carb. You can see in the specs it lists a 5/8-18 fitting for the inlet.

http://www.summitracing.com/parts/HLY-34-160/

The guy gets a 3/8 SAE fitting steel brake/fuel line and it threads in and he says thats what I need. I tell him the specs for the fitting are 5/8-18.

Im REALLY confused now.

I stopped at Lowes and got a 1/4" NPT fitting. It is too big for the fuel pump fitting. What size is it then?

[fordman]

5/8 -18 is the size of the steerign column threads. use the 3/8 that thread right in. that is the correct size since it fit.

[Dragon]

NPT or National Pipe threads come in many sizes. I think I gave the wrong one above 1/4 npt is on my Holley high flow fittings.
From http://www.ask.com/wiki/National_pipe_thread
Commonly-used sizes are ⅛, ¼, ⅜, ½, ¾, 1, 1¼, 1½, and 2 inch, appearing on pipe and fittings by most U.S. suppliers. Smaller sizes than those listed are occasionally used for compressed air. Larger sizes are used less frequently because other methods of joining are more practical at 3 inches and above in most applications.

More listings at http://www.engineeringtoolbox.com/npt-n ... d_750.html

[70_F100]

A Ford fuel pump is generally threaded with NPT threads, not SAE threads. They are DEFINITELY two different things.

Carb inlet fittings on a Holley are 3/8 SAE inverted flare, which is what the guy at NAPA sold you.

You probably need a 1/8" NPT fitting to thread into the pump. Those are available with any number of designs on the opposite end of the fitting. If you're running hard line to the carb, you need a 1/8" NPT male with a 3/8" SAE inverted flare female on the opposite end. If you're planning on using 3/8" flex hose to the carb, you'll need 1/8" NPT male x 3/8 hose.

[Dragon]

Yes mine are special aftermarket Holley Inlet adapters. The don't have flair seats in the them just 1/4 npt with holes to match, no in carb filters. They have been there so long I forgot until 70_F100 mentioned the 3/8.

[OldRedFord]

The fitting on the fuel pump is 5/16.

This is what I ended up getting to get it done.


http://www.oreillyauto.com/site/c/detai ... ord=258560

http://www.oreillyauto.com/site/c/detai ... word=bl530

I need to get some clamps for my connections between hard line and rubber fuel line and between the rubber fuel line and filter. But otherwise I got it.

[70_F100]

The fitting on the fuel pump is 5/16.

This is what I ended up getting to get it done.


http://www.oreillyauto.com/site/c/detai ... ord=258560

http://www.oreillyauto.com/site/c/detai ... word=bl530

I need to get some clamps for my connections between hard line and rubber fuel line and between the rubber fuel line and filter. But otherwise I got it.

Don't be surprised if it leaks.

[OldRedFord]

How come?

[Dragon]

The fitting that goes into the carb needs to be a NPT meaning tapered. The fitting you have is straight so it does not get bigger as it gets deeper that is how a NPT thread seals.

[Ranchero50]

I'm surprised there is even a thread on this. Seems the simplest thing to do (which I usually do) is just have the auto parts guys pull out a reman pump and get the correct fittings for it. The chance for error is greatly reduced too...

Good luck
Jamie

[OldRedFord]

I'm surprised there is even a thread on this. Seems the simplest thing to do (which I usually do) is just have the auto parts guys pull out a reman pump and get the correct fittings for it. The chance for error is greatly reduced too...

Good luck
Jamie

Thats what I did in the end.

[OldRedFord]

Is the threaded fitting on the pump the "out" side of the pump?

Looks like inverted flare to me.