BC

Its a cool problem to decipher, but its still a problem.

Long story made a bit longer - I am designing the fuel system for the 78 around the idea that it will use E85 as the fuel. Its done - planned and outlined in most all parameters of the car, so no turning back now, even if I wanted to.

That said, there are a few requirements that I have put into the plan as fact. These standards may seem over-done, but I wish to have no problems down the line, and will put in extra effort, time, and... whatever else is required now so that I have a proper system.

1) No Rubber in the system.
2) Hard line use as much as possible - and hardline is SS tube with tube nuts
3) Hard line and softline is -10 (front to back, back to front). No smaller size is acceptable. Ethanol needs more hose volume and large return line size is good too.

This is where I have come to alot of frustration, swearing, and consternation. The .625 tube I use is .035 wall - its okay, but sort of heavy, and I have also bought some .028 wall. Thinking it was going to work great, I let it sit there ready for me. I recently did some tests, and the wall is to thin for any bending it seems - it crinkles and flatens when I use this (admittedly) low-tech tool:

(similar):



The thicker wall tube seems to work OKAY, but its not perfect either, and I have alot of bending ahead of me.

Does anyone have any experience, advice, help or shouting to offer on the proper bending of thin wall tube in small diameters?

Hose is going to be used, but VERY sparingly, and near the FRONT of the car, as the stuff I need to use (teflon bore) is about 50 dollars a foot (!) and the fittings are about 50 each as well. Meaning a three foot section, with two ends fitted is 250, without someone paid to properly use the 500 dollar crimping tool.

Jim Devine

What are you using that costs that much? Aeroquip
teflon hose in -10 size should be not much more than $5-7.- ft & the "super gem" ends no more than $18 ea. depending on if straight, 45, 90 degree.
You bolt them on yourself - no crimp needed.
Look up Aeroquip 2807 or aeroquip 666 hose & Super Gem hose ends.
You shouldn't need the all stainless ends- they are expensive. Check fuel compatability
with Aeroquip.
Here are the steel ones:
http://www.aeroquip.cc/aeroquipsuper...or-10hose.aspx

-10 is awfully big.

blown 87

That looks like a quality tool you have, so if you are having problems with bending the pipes it may not be of the correct radius for the material and thickness.

My suggestion is to buy the right tools to properly make the bends.

But if you are a cheap bastard like i am, you can make a poor mans mandrel bend by making the bends before you do the ends by filling the tube up with clean glass beads and hammering the ends shut.

It works better than you may think it would.

PS, I have a old set of "Rigid" brand pipe benders and have made a lot of hydraulic lines for many applications including aircraft using that method.

ptuomov

I filled my ss tubes with sand before bending. Without sand they collapsed visibly, with sand very little.

jpitman2

I suspect part of the problem is the hardness (read not malleable) of the SS. Something that will anneal will bend much better. We cold mandrel bend mild steel fittings to 90degrees, under 1/2" without annealing with very rare problems. Walls are probably thicker than your tubing. Impressive to watch a 2" tube being bent cold. Can you try steel or copper readily? My car has some copper tubing the brake lines up front that somehow dont look factory to me.
jp 83 Euro S AT 52k

Roy928tt

This '78, it's going to make over a thousand horsepower?

A mate of mine recently changed to E85, he had to fatten up his mixtures by about 20% across the range, no other adjustments required in regard to the fuel system. Picked up around 15% horsepower improvement.

I think you are going a bit OTT with your fuel system. Otherwise Jim Devine is right it shouldn't cost you what you have been quoted.

Cheers Roy

BC

Honestly, this is not a random pipe dream filled with arbitrary decisions. Using Engine analyzer pro, and putting in all kinds of real info, boost levels, intake dimensions, etc - the crank HP is at 989hp. -10 front to back is required for the fuel load of ethanol and that power.

I am looking at that site that was listed. I love this site - thanks!

But I do need -10 line because of the reasons stated, and they need to be teflon lined.

BC

Steel may work, but I would be concerned about rust. Uncoated steel will rust because of the water that will reside in the ethanol. Copper is a no.

Normally, the -10 line is supposed to be aluminum, but I would have to anodize or coat every piece.
I was trying to keep to a budget, and the SS is what is allowing the cost to be lower. At least it was.

BC

I had heard about the sand idea. I did not know how to keep the sand in. But I will try that. Thanks

BC

Great Site, Jim, thanks. Steel, if uncoated, is a problem. It needs to be anodized or nickel plated aluminum, or coated steel, or SS.

I do not currently see the teflon bore hose as available in -10.

90 S-4

You might check to see if anyone sells pre-bent ends, 45° -- 90° etc etc
that would enable you to get from A to B anyway ..
The ends could be welded on once they are indexed, you could even use
an occasional (male -female) threaded union to keep it modular.

BC

Hey Joe. The AN parts have all sorts of permutations, but it gets expensive that way - very quickly. I ordered some more -10 SS hardline, and will try the sand or glass bead idea.

BC

I think I have the wrong bender. The type I have has an anvil for the top of the tube as you can see in the picture in the OP. This slides across the tube, causing a sort of friction pressure. Whenever they are listed online they seem to mention copper tube. I think I need this:



They are on ebay. They have a die wheel for the top movement, and mention being able to bend steel tube. Its worth a try, as otherwise I will be spending more money on either crimped teflon lines as I mentioned, or alot of AN joints.

90 S-4

Not screw on AN ones, but a prebent elbow.
I did a quick search and found the place below, it has some of
what I was thinking of.
You should do a long search, maybe check the ebay stores too, to
see if there is a place selling SS elbows at a reasonable price.
Try to find something that looks like the copper fittinings at the
hardware store but are made out of SS.
There are usually ebay adds that are selling large quantities of surplus pieces.
search -- search


http://www.woolfaircraft.com/prebent.html

http://woolfaircraft.thomasnet.com/r...d=&backtoname=

Jim Devine

The super gem steel hose ends are plated and should work fine. Here is the -10 hose:
http://www.aeroquip.cc/fbc10002807-1...eelteflon.aspx


Some hose ends that may help: Note the one that goes from -10 tubing to hose
(second one down) & the banjo ends @ bottom-

http://www.hydraulic-supply.com/pdf/964.pdf


If the stainless tubing is a problem, you could run the hoses long provided you protect & secure them well.
If heat is an issue, this is available:
http://www.hosexpress.com/hydraulic/accessories/624.htm

If there is a doubt, call Aeroquip/ Eaton, they have
plenty of tech support.