Fuel filter change

I would not pinch off a braded line myself. Another question out of curousity, why do you have a filter on either side of the fuel pump? What is the pump going to throw into the fuel? If the tank has a lot of crud in it that you need to change filters more than normally, you might want to install a shut off valve before the filters. Just a thought.

quote:

Originally posted by ANGELO B:
I would not pinch off a braded line myself. Another question out of curousity, why do you have a filter on either side of the fuel pump? What is the pump going to throw into the fuel? If the tank has a lot of crud in it that you need to change filters more than normally, you might want to install a shut off valve before the filters. Just a thought.

Not sure why there is two filters, there when I got it. I seen Butt Plugs when in some Hollywood stores the other week, so maybe one of those could work instead of clamping the hose.

Most fuel pump manufacturers recommend both a pre-filter (inlet) and a post-filter (discharge).

The pre-filter is normally larger, and filters in the 75 to 150 micron range. This keeps fuel tank "garbage" from causing pre-mature failure of the fuel pump while also avoiding limitation of fuel flow into the pump.

The post-filter can be smaller, and normally filters in the 10 to 40 micron range. This keeps all the fine stuff that passes through the pre-filter and fuel pump from reaching the carburetor or fuel injectors.

-G

Thanks for the info George, Does that also hold true for the higher horsepower engines with the higher volume requirements?

With todays crap pump gas, I'm suprised the whole fuel line doesn't need to be a running filter made of a non degrading material. snicker, but thats another topic.

Yes that includes high horsepower applications too.

Some guide-lines:

Plumb the fuel system in metal tubing as much as possible, keep the hose sections as short as possible.

A flexible connection (i.e. hose) is needed between immovable fuel system components mounted solidly to the chassis and
fuel system components mounted flexibly to the chassis with rubber (i.e. the engine). In other words, every fuel system
requires at least one section of hose between the chassis and the motor.

Plumb the pump suction in ½” (AN-8) tubing or hose in applications up to 550 BHP
Applications over 550 BHP should upgrade to 5/8" (AN-10) tubing or hose between the tank and pump

Install a high flow fuel "pre-filter" designed for the fuel pump inlet, ~ 75 to 150 micron
Pre-filters are usually larger than "post-filters".

Plumb the pump discharge in 3/8” (AN-6) or ½” (AN-8) depending upon the application

Install a high flow fuel "post-filter" designed for the fuel pump outlet, ~ 10 to 40 micron

Don't mount filters perfectly horizontal. They should be mounted so the outlet is elevated above the inlet.
This purges air instead of trapping it in the filter.

Inexpensive 3/8" inlet and outlet cannister style in-line filters include:
Fram G15, Wix 33033, Holley 162-523, Mr Gasket 9746

Inexpensive 1/2" inlet and outlet cannister style in-line filters include:
Wix 33299, Mr Gasket 2526

Another option in filtration includes the 2" OD aluminum racing filters shown in the picture in my previous post. They are available in long and short versions; there is a variety of cellulose and stainless steel filter elements, and stainless steel screen filters too; and the filter ends are available with AN tubing connections, NPT connections and Push-Lock hose connections.

-G

Thanks for all the info. Here is a shot of the filter between the tank and the fuel pump. The filter on the other side of the fuel pump seems to be the same size (externally anyway). How can you tell the size of the fitting (maybe by either of these nut size)? The label is gone from the filter so I can't see any numbers, but I see it is an Earls model.

quote:

Originally posted by DOES 200:
Thanks for all the info. Here is a shot of the filter between the tank and the fuel pump. The filter on the other side of the fuel pump seems to be the same size (externally anyway). How can you tell the size of the fitting (maybe by either of these nut size)? The label is gone from the filter so I can't see any numbers, but I see it is an Earls model.

11/16 across the tube nut shows it is a -6 AN fitting, which just might be the root cause of your problem if you are trying to serve a 725hp motor.

Yup, that many ponies get thursty wide open, filter being clear would be a priority with undersized lines.

Man, I sure love that car!

quote:

Originally posted by Dave2811:
11/16 across the tube nut shows it is a -6 AN fitting, which just might be the root cause of your problem if you are trying to serve a 725hp motor.

Yeah, my fuel injection guy also said it may be better with bigger lines, but initially he didn't have the set up and so we just replaced the filters and the pump too (the car had sat too long). Worked great as I really don't pound on the car too hard, but now about a year later I am getting some restriction under heavier load and I only assume it is the filter again. Looks like the car has Earls filter, so I probably need this below according to George's info. How do you guys know this stuff? How does 11/16" translate to 6 AN, I don't have my decoder ring.

Pre fuel pump filter (85 micron):
http://www.summitracing.com/parts/EAR-230206ERL/

Post fuel pump filter (35 micron):
http://www.summitracing.com/parts/EAR-230106ERL/

quote:

Originally posted by DOES 200:
.... How does 11/16" translate to 6 AN, I don't have my decoder ring.

I had some -6 fittings in the garage and just took a quick measurement. There is no secret code to speak of, but when you get into plumbing, it can be quite confusing to keep it all straight. AN, SAE, NPT, JIC, 37*, 45*, BSPP and bubble flare!

The numbering of AN tube fittings relates to the size of the tubing, not the wrench size required by the tubing nuts. The "dash" numbers express the tubing size in sixteenths of an inch:

AN-4 = 4/16 = 1/4" tubing

AN-6 = 6/16 = 3/8" tubing

AN-8 = 8/16 = 1/2" tubing

AN-10 = 10/16 = 5/8" tubing

the sizing of plastic & metal tubing is based upon the outside diameter, the sizing of flexible (i.e. rubber) tubing (aka hose) is based upon the inside diameter.

-G

quote:

Originally posted by Cowboy from Hell:
The numbering of AN tube fittings relates to the size of the tubing, not the wrench size required by the tubing nuts. The "dash" numbers express the tubing size in sixteenths of an inch:

AN-4 = 4/16 = 1/4" tubing

AN-6 = 6/16 = 3/8" tubing

AN-8 = 8/16 = 1/2" tubing

AN-10 = 10/16 = 5/8" tubing

the sizing of plastic & metal tubing is based upon the outside diameter, the sizing of flexible (i.e. rubber) tubing (aka hose) is based upon the inside diameter.

-G

What the hey, now I am confused. If a 11/16 wrench fits onto the tube nut of the filter, would it still be an AN6 filter I need?

quote:

Originally posted by DOES 200:
What the hey, now I am confused. If a 11/16 wrench fits onto the tube nut of the filter, would it still be an AN6 filter I need?

Yes

Talked to my fuel injection guy and he thinks the first filter may just be a screen, so I need to just get it off and take em appart and see what I need. Anyone have ideas about preventing gas from flowing out all over. Butt plug idea may not cut it. I would think there would be some plugs out there by now that may even screw into the hose connection to temporarily hold the gas back. I am sure my full tank won't help things either.

You could siphon off the majority of the fuel. Put it in your other vehicles and keep the last 5 gallons to refill the tank. With an empty tank, then you can re-plumb the system as needed, or at least install a shutoff valve for future filter changes.

Some place in the line going back to the tank is a rubber hose. Pinch the hose together with a Vice-Grip pliers and work fast. There will likely be a little seepage.

quote:

Originally posted by Bosswrench:
Some place in the line going back to the tank is a rubber hose. Pinch the hose together with a Vice-Grip pliers and work fast. There will likely be a little seepage.

I looked but it is all steel braided line. I do like the siphon off idea as I was just about to fill my Group 4. Nice idea, didn't even think of that.

Why not just disconnect the line at the top of the tank? This would stop the siphon.

Well, siphoned almost all the gas from the tank & ordered Fuelab filters 75 and 10 micron. My FI manufacturer said the Earls higher micron are more for carb application and are not very good filters anyway & I had too high micron. Fuelab was pretty expensive, but they come in tomorrow. I have one tube elbow fitting on the filter between the fuel pump and then engine, but there is one nut on the elbow that connects to the filter. Before I go wrenching on that, is that nut on the elbow joint supposed to be movable, or do I just attempt to hold that steady and turn the filter? All other hose connections have two nuts on all the hoses so you know the one on the filter turns while the hose nut stays steady. Thanks...rookie at work.

A photo of the area you are describing would be helpful. Hard to picture from your description. Usually plain elbow fittings have male threads, but if it is a 90 deg hose fitting, then it would be a female nut.

quote:

Originally posted by Dave2811:
A photo of the area you are describing would be helpful. Hard to picture from your description. Usually plain elbow fittings have male threads, but if it is a 90 deg hose fitting, then it would be a female nut.

Yes, it is that bottom photo, those nuts spin, correct? One end is directly on the filter and on the other end is the braided hose set up. Would take a photo, but it is real tight in that area, not even sure I can fit my hands up into that area to do wrench work untill I get it up on the lift and see. Then I will prepare my Neosporin for hand scrapes and vodke to help wash down the spewing gas (however if I am quick with the connections, then that 6AN plug sure is going to help stop the gas temporarily till I make the filter switch).

quote:

Originally posted by DOES 200:
Yes, it is that bottom photo, those nuts spin, correct? One end is directly on the filter and on the other end is the braided hose set up......

Yes, the nut spins. Your filter has a male thread so hold that steady.

I'll have to try the Neosporin and vodka remedy. The Prestone martinis leave me feeling a little "off".

quote:

Originally posted by Dave2811:

quote:

Originally posted by DOES 200:
Yes, it is that bottom photo, those nuts spin, correct? One end is directly on the filter and on the other end is the braided hose set up......

Yes, the nut spins. Your filter has a male thread so hold that steady.
Thanks, I figured those nuts we meant to turn, but I leanred not to assume things. Ha yeah I almost forgot about the Prestone martini, I had to revisit it. http://www.poca.com/index.php/...ery/?g2_itemId=18589

I'll have to try the Neosporin and vodka remedy. The Prestone martinis leave me feeling a little "off".

Goter done. I ordered Fuelab filters 10 micron for post filter and 75 micron for the pre pump filter. Much better filters than the set that was on the car (which my FI guy says were for a carburated car, 35 micron too big). Expensive stuff, over $100 per filter, but the car screams now, no hesitation whatsoever. The filters were about double length and over double diameter than the other set, almost didn't think I could fit them in (and I choose the smallest fuelab filters).

Good news Jan!

-G