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Race Car Plumbing

Over the years I have seen and used just about every method to plumb a race car for the vital fluids that it requires to operate. Forty plus years ago the hot ticket was clear or tinted fuel lines running from the fuel pump to a an inline fuel filter and then on to the carburetor. As you might imagine these lines getting a bit close to something hot or even warm for that matter would have a disastrous effect and "carb" fires were quite the norm at the dragstrip. A bit later and of course still in use today was the denser and sometimes reinforced rubber fuel line. This was a bit better, but once again it didn't take much to have one come loose and plumbing the stuff in tight areas wasn't a cup of tea either.

Today, you normally see braided line, the new push-lock line or hardline. I have not used the push-lock stuff yet so I don't have any information to share on it. Hardline can look really nice, but you need to be good with a tubing bender and plan on scrapping your share of line from mistakes. The upside is that normally you can find everything you need to plumb hardline in a well stocked auto parts store. And done right, it does look nice so it's a good alternative to braided line if cost is an issue.

Most of the fuel, oil and water connections that I have done lately have been braided stainless steel line or AN line. Once you get used to the sizing routine, making up your own braided lines isn't that difficult. There is a drawback that in really tight areas, you may find that you simply can't make this type of connection even with the variety of adapters that are now available. And if you have a local shop close by, you can avoid making the lines yourself as most of them will do the work for you, sometimes at no charge if you purchase all of the parts from them. Just make sure that you write down everything that you need and take good measurements. A rule of thumb that I use is to put the hose ends in place on the components then measure the distance between the hose end nuts, if what you are doing involves turns or corners, then of course you have to allow for that increase in measurement as well. AN does not like to be in a strain, nor twisted and it's best if the hose is laid out to have a natural flow to it.

If you have decided to make your own hoses, the tools are pretty basic except if you're worried about scratching the anodized coating on the fittings. If you are, then a nice set of AN wrenches is what you will need and even those will have to be used with care. On a race car, there are probably a handful of fittings that come apart on a regular basis and while I try to not damage a fitting, I don't worry to much about the looks either. Cutting AN hose can be accomplished in several ways. I have used a sharp chiesel, hand-sledge and a block of wood to cut hose, an air-operated cutoff tool and my favorite is a pair of cable shears. A pair of tree branch cutters will work to up to about -12. You also need a roll of masking or electrical tape, WD-40 spray, a vise with soft jaws, open end wrenches, a sharp pair of side-cutters, a marker pen and some patience.

Begin by taking apart your first fitting, then apply the WD-40 to both the inside of the fitting, the threaded area, the nipple threads and a bit on the end of the hose. Carefully start the end of the hose into the fitting with a turning and rolling motion, what you want to do is get the cut ends of the stainless into the hose end before it starts to unravel on you. Continue to twist and push the hose end in place until it bottoms out on the end of the hose. Take a rag and wipe off any excess WD-40 and place a mark at the bottom of the fitting on the hose. Now, holding the hose just behind the fitting, start the nipple into the fitting and hose, you will get a little resistance and probably have to push the nipple into the fitting. Carefully - I SAID CAREFULLY, start the threads of the nipple into the hose end. If you screw this up, the hose end is junk. Just remember that these parts are aluminum and that the threads will damage very easily. You can normally get a turn or two on the threads before you will need to result to wrenches, I do it this way to prevent damage to those threads. Place the hose end in your vice soft jaws so that you can see the mark that you made and have a good grip on the hose. You want to continue to apply pressure on the hose pushing it into the fitting as you thread the nipple in with a wrench. If the mark you made starts to move away from the hose end by more than a sixteenth of an inch, then stop, back out the nipple and push the hose end back in place, then start again. The hose has to stay in position to completely capture it in the fitting and keep it from leaking. Continue to tighten the nipple fitting into place until you have about a 1/16th inch clearance between the nut of the nipple fitting and the nut of the hose fitting. You can line up the flats of both for a nice look if you wish.

Okay, now you have the first fitting done. After a bit of practice, you'll be able to install these faster than you can read the description of doing the work. Don't worry if your first few fittings take time to complete. I remember the first one I did, I was so uncertain of it that I took it apart again just to make sure I was doing it correctly. After making sure the length of the hose is what you need, and having marked it with your pen, wrap masking tape or electrical tape tightly around the mark, covering it. I prefer masking tape and a black marker pen as I can see the mark through the tape. Using your preferred method of cutting and cut the hose on the mark and make sure to cut the hose as squarely as possible to have a good fit in the hose end. Once you have cut the hose, you may find a few strands of stainless steel that did not cut cleanly. Use your sidecutters to trim those off and you're ready to install the other fitting. Don't forget to remove the tape before putting the fitting in place. Once you have the second fitting in place, using either WD-40 or brake cleaner, shoot some through the hose in both directions, this will help clear out any bit of matter left over from the cutting process. Do this until you are positive that you have a clean hose before fitting it to the car. One last step is to lube the hose end and the connector nipple with WD-40 before you do the final assembly and each time you take the fitting apart, it's a good idea to re-lube it before you re-assemble it. Remember what I said about the threads, they can be damaged very easily and the lube can help prevent that.

So there you have it, a simple process and although the parts involved can be expensive to start with, you have to remember that they can be used over again and again. Some of the fittings on our Camaro project and my dragster are ones that I bought 12-14 years ago when I was racing another car. Along with the nice looks that stainless has, you also have the knowledge that the plumbing connection is secure and that it should never leak. Plus you did it yourself and if you decide to make changes to components, you don't have anything holding you back.

Note: Here's a few pictures of the vent hose that I made for the car.

I used -6 AN for this little project and what we have here are the two end fittings, one of which is a 90 degree unit and the bulkhead fitting with two locking nuts.

This is looking back into the area just behind the left tail light lense, in fact the outside location of this vent will never be seen as it fits right behind the lense with plenty of room. Kind of trick I thought.

My closeup photography skills need some work, but wanted to show the fittings taken apart. The red is of course the hose fitting and the blue is the nipple fitting. You can get fittings in polished clear and black, but the red/blue combination is the most common.

The hose was just a few inches too long and needed to be trimmed. Once you have it marked with a sharpee, you can wrap the hose with a couple of trist of masking tape and then re-mark your cut. A tip is to always wrap in the middle of the cut, that way the leftover hose that might be used for another project will already have it's end wrapped. If the ends aren't wrapped, it will eventually unravel itself. Another tip is when you are assemblying the hose, you can wrap masking tape around the bottom edge of the hose fitting to serve as a guide for making sure the hose is not pushing out, rather than a mark with a sharpee that is.

And bingo, we have added both ends, cleaned out the hose and connected it to the bulkhead fitting and the fitting that came with the fuel cell.