Building Custom Fuel Line with 85 Vette O-Ring Filter

Forum member "MNJack" posted the following question in a Topic Folder, "Is Lars on Vacation?" I'm re-posting it under this topic heading so people can see that we have an interesting technical topic going here for future reference. This is a good subject, since I see a lot of Vettes out there with some dangerous-looking rubber fuel line hooked up on the pressure-side of the fuel system in order to accommodate an in-line filter. A hard-plumbed, screw-on filter is much safer, more reliable, and looks much more professional when installed on the pressure side of the fuel system (between the pump and carb). I'll provide some additional info as stated:

From MNJack: I want to use the ['85 Corvette High Pressure Fuel Injection] GF481 fuel filter in my 68 bigblock. I bought one (actually I have a purolator f33144 - same thing) because the threads were the right size for the stock fuel line. Of course, the fuel line does not seat properly to the filter, because the filter is designed to take an O-ring fitting. I have never seen this fitting so I am not exactly sure what is involved. Is there any way to modify the stock fuel line fitting to accept the GF481 ? You mentioned that you have used a fuel line for a GM truck (not sure what year or model) to fabricate fuel lines that will fit the GF481. What is the part #?

I like that the fuel line and filter are correct for a corvette ! ..... a 1985 corvette! Thanks, MJ

Response from Lars:

I'm back from vacation - I went down to Cozumel for a little over a week, so I'm back at the office playing catch-up now after my absence... I think the only way to really solve this type of problem is to simply never come back from vacation.... My wife tells me that Mexico is the only place we ever go where I don't end up working on Vettes during vacation.... good thing I don't do work on VW Beetles, though!

Yes, I have all the info you need to fabricate an awesome, pro-looking ultimate-quality fuel line using the '85 Vette high pressure fuel filter. As you note, one of the features of this filter is that it is designed for use with a special O-Ring'ed fitting, and therefore you cannot simply flare up a couple of tube ends to mate up to it (the O-Ring fittings are the same as those used on the air conditioning system lines), and you cannot easily fabricate the special O-Ring'ed ends yourself. I have the part number and the cost of an available straight piece of GM fuel line that has the correct fittings on both ends, and it even has some of the spiral-wrapped "armor" on it that you can use on your fabricated line. I have all the part numbers at home, so I'll have to bring the info in with me tomorrow and send it to your then, if that's okay.

What you do, of course, is use the straight piece of pre-made GM line, which is actually for a 3-ton truck chassis, and cut it in half. You thus end up with two pieces of fuel line, each of which has an O-Ring fitting assembly on its end. You screw the O-Ring'ed ends into the '85 Vette filter, and then bend up the lower end to mate up to your fuel pump, install an inverted flare fitting, and flare the end. Then bend up the upper section to mate up to your carb inlet, install an inverted flare fitting, and flare that end. You then end up with a bullit-proof, pro-looking, factory-like fuel line with an easily-replaceable, high-volume, extremely reliable fuel filter. You can even slide the armor spiral-wrap onto the lower section of the line before you flare the end to make the line impervious to stone/impact damage and to give it a real "factory" look.

If you don't have a lot of experience with bending up and flaring lines, I recommend that you buy yourself a 42" long piece of 3/8" brake line from your friendly NAPA store (cost is about $4) and cut & bend up a trial piece of line before you chop up the nice GM line. You can then use your trial piece as a template when forming your "real" line from the O-Ring'ed line.

I'll write myself a reminder note to bring the info in with me tomorrow and paste the note over my speedometer. Oh... wait a minute... I don't pay any attention to the speedo.... I better paste it over the oil pressure gauge...

Contact me with any questions. I'll post more info in the morning....

_______

Okay - here's the info for the line:

GM part number 22527595 (Group 3.163) is a straight piece of 3/8" steel fuel line with a correct "O-Ring" fitting with a rubber O-Ring on both ends. The line is about 8 feet long or-so. The fittings and O-Rings on this line will screw right into the '85 Corvette High Flow High Pressure fuel injection fuel filter. This line also has 2 pieces of the spiral-wrapped "armour" on it that you can utilize as you see fit when you fabricate your custom line. I did not have cost info, but I seem to remember that it was somewhere in the range between $10 -$20.

You'll need a 3/8" Tube Bender (Snap-On and Blue Point both sell a nice hand-bender that will bend 3 sizes of tube up to 3/8". Eastwood also carries them) and a double flare tool for 3/8 tube (there are some nice double-flare kits out there that will flare multiple sizes of tube) as well as a tube cutter. Armed with these tools, a grease pencil, an X-Acto Knife and a small half-round swiss file, you can bend up any fuel line you want utilizing the good '85 Vette filter.

Cut the 22527595 line in half, and bend up a line from the filter to the fuel pump and another line from the filter to the carb. If you buy a 42" long piece of 3/8" brake line from NAPA, it will have 2 inverted flare fittings on it. Cut the end off this NAPA line and take the fittings. Then use the rest of the NAPA line to trial-bend your two tube sections before you try it on the nice GM line. Use the inverted flare fittings on your new bent up custom line at the fuel pump interface and at the carb interface. Your new lines will thus have O-Ring fittings on one end that will screw into the filter, and inverted 45-degree double-flare fittings (that you will flare with your flaring tool) on the other end for screwing into the fuel pump and carb. This produces a neat-looking and highly reliable fuel line for your Vette engine, and it has a very stock-looking appearance even though it's not stock. With a little practice, you'll be able to use the bending tool very quickly to make accurate, good-looking bends. I use a grease pencil to mark the line for bends as I fit the line to the engine one bend at a time. It works well.

Before you flare the cut ends of your tube sections with the flaring tool, it is imperative that you de-burr the ends of the cut tube extremely well. I use an X-Acto knife, and run the knife around the inner diameter of the tube to cut out the sharp ridge that the tube cutting tool leaves. Then, I use a small half-round Swiss file to file the inner diameter of the tube to eliminate every trace of the ridge. Once the tube-end prep is perfect, you can then slip the inverted flare fitting into the tube and use your double-flare tool to fabricate a great-looking flared end that will seal up well.

Once your lines are fabricated, you can put a little polishing compound on a rag and rub your lines through the rag. This will polish the plating on the lines (usually zinc) and make your lines look almost chrome. Pretty cool.

If anyone has questions on this process, or wants any specific information, please feel free to contact me.