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Leonard_Smith_nz

Active Member
All,

I'm planning the layout of items to go on the firewall. I've purchased the Van's firewall forward kit (RV7/9), which shows the fuel pump inside (of the cockpit) and the gascolator on the right hand side (seen from the pilots seat). Now, in my 6 I've got the fuel system exiting on the left side and to be able to use the supplied fuel hoses I've got the plumb the system to run across the firewall to meet up with the gascolator on the right side.

My personal preference is to have to fuel pump forward of the firewall and I'm wondering if this is OK ?? One option is to place it inside the CSU recess, which I don't need, as I'm going FP.

I may need to consider the height of the fuel pump (is this correct?) and well as the temperature inside the engine bay before I make a final determination.

Any thoughts appreciated.

Regards,
Leonard (RV6 in New Zealand)
 
fuel pump location

Leonard,
If it is any use, I mounted my pump below the fuel selector valve in the little centre pod that Van provided. The pump is supposed to be mounted at 45 degrees according to the leaflet and I'm told this is to do with priming. Anyway 45 degs is quite OK in terms of pipework. It simply requires a lazy "S" with a spring bender to get the pipe from the pump to the selector to fit.
I used pipe fittings on the side of the pod for the two tanks plus the pipe to the gascolator. This was for simplicity but also so that I could do the work on the bench.

There is a bonus. I mounted a small red pilot light above the fuel selector which is wired in parallel with the pump so that it comes on when the pump is operating and lights the selector.

The pipework to the Gascolator is simply run on the right not the left in one single run.

My thought was that I wanted the pump to be as low as possible to self prime and I didn't want it in the engine bay.

It worked for me but I guess there are many alternatives.

Ted RV-6
(90% complete 90% to go!)
 
I mounted mine in the cockpit

I built a floor mounted center console and the aux pump is in there. I mounted it as low as I could get it consistent with my console floor which is a plate between the two center most floor stringers. The fuel comes in from the tanks, goes through individual tank filters, to the selector valve system then to the aux. pump, then to a "T" with a 1/8" side port and 3/8" through port, the 1/8" line goes to a primer solenoid valve and out the other side to a bulkhead fitting on the left side of the firewall, the 3/8" line goes to the left side of the firewall where it is connected to a bulklhead fitting also. On the forward side of the firewall the primer line becomes a series of "T"s and lines supplying primer fuel to three cylinders on the O-360-A1A (the other cylinder's "primer port" is used as the Manifold Pressure source - rear right cylinder). The 3/8" fuel line goes to the engine driven fuel pump. There are a couple of tricky items in this area. One is the special fittings required on the engine driven fuel pump or carb (I forget which and I shipped my builder's log and photo record to Oshkosh this afternoon). I believe the firewall forward drawings point this out (I bought a set just to help nail down the requirements when I was at this stage in my project). The other is the primer fittings. They have to be installed on the lines for each cylinder with a torch. I bought the AN800 primer fittings from Aircraft Spruce (p.112 in the 2004-2005 catalog) and and also the Portasol Cordless Butane Soldering tool Kit (p.537) and made the installations with silver solder. I was concerned about the amount of butane included in the kit and did a lot of research to find more. It turns out the amount provided is more than enough to do the job. The system has been trouble free with several long trips (California, Florida, etc.). I would keep the fuel pump low and inside the cockpit if I were you.

Bob Axsom
 
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Update from Leonard

Guys,

Thanks for your replies.

What happened was that some time expired between doing the basic fuel plumbing and the arrival of the engine/firewall forward kit. As a consequence I had done quite a bit of work on the interior, including the carpets etc, all based around where the fuel lines currently are.

While, with the benefit of hindsight, I would follow your advice without hesitation, right now I'm trying to save myself some double work.

The most important question to me is: "Does placing the fuel pump in the engine bay constitute a safety hazard?".

I appreciate that it may not be the best place, but with sufficient shielding to help keep the heat away, I'm hoping that it's still acceptable. Any flyers out there with this configuration that would care to comment?

Thanks for the input.

Regards,
Leonard
RV6 in New Zealand
 
That's Where it Was on My Piper

I owned a Piper Archer II for 22 years with the fuel pump mounted on the forward side of the firewall and it worked fine with no shielding. I'm sure yours will too.

Bob Axsom
 
Leonard,
If you are going to mount the pump in the csu recess and you are concerned about it being forward of the firewall, could you just put a plate over the recess, after the pump is installed and thus it would be behind it's own little firewall?
Not being a builder and not knowing exactly what this all looks like, might make this idea mute, as you might not be able to install a plate. But it was just a thought I had, after reading your post. Maybe not doable and maybe doable?
Many carbureted certified aircraft have the boost pump ahead of the firewall, some are located in a mounting box of sorts, separating the pump from the other forward of the firewall components and others aren't.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at you own risk."
 
The main thing to remember is to keep the pump low. These electric pumps like to "push" rather than "pull" fuel. The pump should be mounted as low as the bottom of the tank if possible.
Mel...DAR
 
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