SS Braided Teflon Flex Line Minimum Length?

[Sparky]

I searched the forums and couldn't find any info on this.

First off, I am building an RV-7 with an Aero Sport Power ECI IO-360-B1B with vertical induction and a AFP fuel injection system. I am also installing a Raven inverted oil system.

Is there a minimum allowable length for stainless steel braided flexible oil / fuel lines between the engine and the firewall or between the engine and a clamp on the engine mount tubes? I am sure it depends on many factors, including hose size.

Here is my dilema. I am installing oil lines for the Raven inverted oil system. The Raven Install Manual states the following for the oil valve (that I'm mounting on the firewall):

"For horizontal-screen sump engines, the Oil Valve must be located such that its center port is vertically aligned as close as possible with the sump screen access port, it can be positioned any place horizontily on either side of the engine. For vertical-screen sump engines, the Oil Valve must be aligned such that its center port is vertically aligned as close as possible with the bottom surface of the sump. You can rotate the new adjustable Raven oil valve so that the ports will line up to allow the easiest and shortest routing of the hoses."

How short is too short? The (hefty) #10 hose between the sump port on the back of the engine and the center port on the oil valve could be as short as about 8". With a #10 line not being very flexible it is difficult to put much slack in the hose and I'm afraid engine shake could damage the line over time.

Should I place the oil valve further outboard to allow more hose (so I can create more slack in the hose) between the oil valve and the engine to allow for engine movement? Obviously, this would not be the "shortest [possible] routing of the hoses", but would be the "shortest practical routing of the hoses.'

Any help is appreciated.

[TS Flightlines]

Paul---8 inches of assembly length will give you about 6 1/2 inches of hose length, depending on your stem lengths. If your accessories are pretty straight, then that length will be fine. I dont think that you will have enough motion to need anything longer---as long as the 8 inch assembly length included alittle bit of slack. If not---you will need some--maybe extra 1/2-3/4 inch. If not, and you do get some motion, you could possibly pull the fittings (doubt it), or maybe fracture the liner--more possible. Hope this helps.
Tom