Suggestions on line between primer valve and gascolator

[drill_and_buck]

I am looking for pros, cons and options for installing a fuel line between my gascolator and electronic primer valve.

Both the valve and the gascolator are affixed to the firewall and are approximately 12 inches apart. There is no relative movement between the two attached points.

I was going to purchase an expensive flexible fuel line when an A&P stopped by and said that was an overkill. He suggested I use a copper line, similar to what I installed on the outbound side of the primer valve. Someone else mentioned that wasn't a good idea and suggested a stainless steel line between the two.

I didn't think twice about using copper on the outbound side of the primer valve since it is unpressurized and seldom used. However the line between the gascolator and the primer valve remains pressurized during engine operations.

I like the idea of using a copper line but do not have a good understanding of the pros/cons. Does anyone have any experience using a pressurized copper line in the engine compartment?

I would appreciate any suggestions or comments from the RV community on using something other than than a traditional flex fuel line for this task.

Mike
Finishing
Hope to be at the airport this summer

[Mel]

I never recommend a copper line where it is subjected to vibration. Vibration will work harden copper and it will break. I would use aluminum between the gascolator and primer and stainless steel with a good service loop between the primer and the engine.

A lot of people use copper and it WILL work. But you need to keep a careful eye on it.

[Ron Lee]

I used to have primer lines then at one inspection found one line that had cracked (unknown material). I removed the entire primer system and never looked back. Carbureted O-360.

[L.Adamson]

Originally Posted by Ron Lee

I used to have primer lines then at one inspection found one line that had cracked (unknown material). I removed the entire primer system and never looked back. Carbureted O-360.

On the other hand, my primed engine starts much too easy with priming on these cold winter days. I wouldn't want to do without it. I have no desire to pump the throttle.

L.Adamson -- RV6A

[Ron Lee]

Start the prop turning then pump the throttle. Whatever works. Mine starts fine and I have one less system to fail. It gets cold here too.

As far as the posters concern, don't cheap out on whatever line you use. What would happen if the material you use cracks partially or completely. If it would result in loss of fuel continuously, I would use the expensive flexible line.

[jsharkey]

Rigid mounts for gascolator and primer solenoid.

Short copper line with flex bends - mainly to aid installation.

Inspectable through the oil door.

Well worth keeping an eye on.

YO360-A1A Starts first turn in chilly north east at 10F after overnight preheat with Reiff cylinder and sump system and six full seconds of prime.

Jim Sharkey
RV-6 - Phase 1 ~30 hrs so far

[alpinelakespilot2000]

Jim-
Any suggestions on how to perfectly drill the mounting bracket to the primer solenoid or do you just have to try to get close and then oversize the holes a little?

[jsharkey]

I measured the hole centers on the solenoid and then marked, center punched and drilled the bracket. Guess I got lucky because it fitted without any hole "pulling" needed.

There is no locking mechanism in the solenoid so I used Loctite on the screws. Not shown in the picture - I also drilled a couple of safety wire holes in the bracket and safety wired around the pipe fittings for extra security.

I am sensitive to the copper pipe since I used to fly a PA-12 that was forever cracking copper primer lines - mind you they were terribly routed and secured, and soldered to the cylinder head nozzles - but at least they weren't under boost pump pressure for a chunk of time every flight. Failure was always in the pipe close to the soldered joint.

Jim

[L.Adamson]

Originally Posted by jsharkey

Rigid mounts for gascolator and primer solenoid.

Short copper line with flex bends - mainly to aid installation.

Inspectable through the oil door.

Well worth keeping an eye on.

YO360-A1A Starts first turn in chilly north east at 10F after overnight preheat with Reiff cylinder and sump system and six full seconds of prime.

Jim Sharkey
RV-6 - Phase 1 ~30 hrs so far

Based on my nearly 40 years in the heating/air conditioning industry, and lot's of small copper lines with flare fittings..........Its my opinion that setup will work okay. Mine is similar with two loops, as the solenoid sits about 8" above the gascolator. At least the firewall isn't a high vibration area (at least no more than an outside condensing A/C init), and the copper pipe doesn't move back and forth to promote quick work hardening. It's a fact, that if copper tubing is bent back and forth just a few times, that it will work harden in just minutes.

But I don't see any signs of the 1/8' piping going from my gascolator to the solenoid valve, or from the valve to three ports on my engine having any indication of work hardening. The lines going to the engine also have loops in them, as well as slack to slightly flex. I'm also very good at forming flares with these smaller tubes, so I don't expect them to break either. My airplane does only have about 150 hrs, but I'll also keep an eye on it. In the meantime, I'm not worrying about it, or even going to feel that it has high potential as a failure point.

These small 1/16" copper lines that connect to the expansion valve or coil in the AC evaporator coil that sits on top of a furnace encounter more pressure (60 - 400 lbs) than we encounter in our setups. And they can easily last 30 or more years. There can also be numerous flare fittings in the coil too.

What we don't want to do, is re-bend or re-coil a copper tube. That will definitely give it a head start on work hardening. Just junk it and make another one.

L.Adamson --- RV6A

[az_gila]

Originally Posted by alpinelakespilot2000

Jim-
Any suggestions on how to perfectly drill the mounting bracket to the primer solenoid or do you just have to try to get close and then oversize the holes a little?

The 8-32 holes are opposite corners of a 0.4 by 0.59 inch rectangle.

Make sure you orient the part correctly -- by some wierd logic, they use the port marked 2 as IN and port 1 as OUT.

Page 44 of 131 of the PDF here...

http://www.parker.com/literature/Flu...at%2003_08.pdf

I couldn't match exact part numbers, so check the other dimensions on the data sheet first....