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-   -   2-gauge master through firewall (https://vansairforce.net/community/showthread.php?t=162524)

flyingbeaver26 07-22-2018 10:06 PM

2-gauge master through firewall
 
I have a CS prop and will be mounting my battery in the rear. The Van's FWF kit comes with BARELY enough 2-gauge wire from the master solenoid to the starter solenoid. I'm annoyed.. I literally have enough cable to go about 1" from my opening in the firewall. So I need to penetrate the FW right under the starter solenoid tab. The crimp on the cable may stick into the penetration conduit.

Since we are supposed to be using steel here for the conduits, I have a problem. I could put heat shrink around the crimp fitting an a small piece of fire sleeve around that to insulate it from the conduit.

Has anybody else had this issue? Should I just go buy $70 of 2-gauge cable to get a longer piece that works?
Also, the 8 is the only kit that has a battery behind the FW option I believe, What hardware did you use to get your battery cable through the firewall?

Thanks for your assistance.

Wunderon 07-23-2018 12:31 AM

hmm, I have the Van?s wire kit and my AWG2 was long enough to go from the aft-mounted master to the firewall plus about 16?, via the left gear tower. I basically routed per the OP10/11 plan. If you are buying a replacement might consider welding cable. B&C and Amazon have various choices. I?m using closet flanges for penetrations. https://www.amazon.com/Stainless-Ste...ref=mp_s_a_1_3

rv8ch 07-23-2018 12:49 AM

lifepo4 battery?
 
Or you might think about putting a very light LiFePo4 battery on the FW and save a lot of total weight and long wiring runs. Earthx has some nice batteries.

Strap a small tool bag into the rear baggage area if you need help with W&B when flying solo.

Lufthans 07-23-2018 02:14 AM

The RV4 typically has the battery behind the firewall, on the floor in the compartment between the pilots calves. I believe it then is pretty much up to the builder to figure out a way to penetrate the firewall.

On ours, the builder has used some of those ball things. Aircraft Spruce sells all sorts of firewall fittings.

But really, do yourself a favour and stick to how things are supposed to be and don't go modifying for want of a piece of wire.

My $.02

Hans

Quote:

Originally Posted by flyingbeaver26 (Post 1275443)
I have a CS prop and will be mounting my battery in the rear. The Van's FWF kit comes with BARELY enough 2-gauge wire from the master solenoid to the starter solenoid. I'm annoyed.. I literally have enough cable to go about 1" from my opening in the firewall. So I need to penetrate the FW right under the starter solenoid tab. The crimp on the cable may stick into the penetration conduit.

Since we are supposed to be using steel here for the conduits, I have a problem. I could put heat shrink around the crimp fitting an a small piece of fire sleeve around that to insulate it from the conduit.

Has anybody else had this issue? Should I just go buy $70 of 2-gauge cable to get a longer piece that works?
Also, the 8 is the only kit that has a battery behind the FW option I believe, What hardware did you use to get your battery cable through the firewall?

Thanks for your assistance.


Carl Froehlich 07-23-2018 08:57 AM

Firewall forward kits will never meet all applications. As I use a difference governor, alternator, oil cooler and such I don?t use them.

I stopped using aircraft #2, #4 or #6 wire a long time ago. Go on Amazon and get US made welding cable for all these runs. More durable than Tefzel wire, very flexible and less expensive.

If interested, send me your email and I?ll show you how I mounted and configured two PC-625 batteries in my new RV-8 project, one aft and one in the forward baggage well. Using another RV-8 W&B data and a sharp pencil it looks like a nice set up for a IO-360M1B with Hartzell BA prop.

Carl

Lufthans 07-23-2018 04:21 PM

Quote:

Originally Posted by Carl Froehlich (Post 1275492)
I stopped using aircraft #2, #4 or #6 wire a long time ago. Go on Amazon and get US made welding cable for all these runs. More durable than Tefzel wire, very flexible and less expensive.

Carl

Really the only reason to use Tefzel is that when smoking hot, it doesn't give off nearly as much toxic fumes as PVC clad wire does, so that you might survive an electric fire.

Other than that, Tefzel is terrible. It is brittle, expensive, hard to strip, and why does it have to be predominantly white?

Yet, in all my aircraft wiring, I use it. Don't fancy dying from suffocation...

Hans

sf3543 07-23-2018 05:01 PM

T
 
You could get a firewall bulk head cable connector, which is basically an insulated threaded rod that penetrates the FW. That would allow you to use the long piece to the FW from the battery and then get a shorter piece forward of the firewall. Also, makes a better sealed penetration.
You will have two additional terminals for the wire ends though.
Summit racing sells them for less than $10.

Carl Froehlich 07-23-2018 05:29 PM

Quote:

Originally Posted by Lufthans (Post 1275574)
Really the only reason to use Tefzel is that when smoking hot, it doesn't give off nearly as much toxic fumes as PVC clad wire does, so that you might survive an electric fire.

Other than that, Tefzel is terrible. It is brittle, expensive, hard to strip, and why does it have to be predominantly white?

Yet, in all my aircraft wiring, I use it. Don't fancy dying from suffocation...

Hans

Welding cable is not PVC insulation.

I took a torch to the welding cable before I installed it. It chard a little, but did not burn. The Tefzel cable did not fair as well.

I do use Tefzell wire for all application other than #6, #4 or #2.

Carl

Reformed SeaSnake 07-23-2018 06:34 PM

Bit the bullet and bought more
 
Quote:

Originally Posted by flyingbeaver26 (Post 1275443)
I have a CS prop and will be mounting my battery in the rear. The Van's FWF kit comes with BARELY enough 2-gauge wire from the master solenoid to the starter solenoid. I'm annoyed.. I literally have enough cable to go about 1" from my opening in the firewall. So I need to penetrate the FW right under the starter solenoid tab. The crimp on the cable may stick into the penetration conduit.

Since we are supposed to be using steel here for the conduits, I have a problem. I could put heat shrink around the crimp fitting an a small piece of fire sleeve around that to insulate it from the conduit.

Has anybody else had this issue? Should I just go buy $70 of 2-gauge cable to get a longer piece that works?
Also, the 8 is the only kit that has a battery behind the FW option I believe, What hardware did you use to get your battery cable through the firewall?

Thanks for your assistance.

I have a similar set up to yours and bought the longer #2 Tefzel. It was definitely not the most expensive ?add-on? I had to one of Vans sub kits.

I ended up using the #2 that came with the kit to run the starter solenoid to starter, the battery ground, and the short length between the battery and the master solenoid mounted on the battery box. I have a couple feet left, but less than what I thought I would have.

As far as the firewall penetration, there are a number of good threads on VAF which discuss that. ACS sells a steel pass-through for ~$60. I made something similar using steel conduit fitting from Home Depot.

Lufthans 07-24-2018 03:32 AM

Quote:

Originally Posted by Carl Froehlich (Post 1275584)
Welding cable is not PVC insulation.

I took a torch to the welding cable before I installed it. It chard a little, but did not burn. The Tefzel cable did not fair as well.

I do use Tefzell wire for all application other than #6, #4 or #2.

Carl

In that case, please disregard my remarks :-)

I'm finishing a car build from scratch and have used welding cable there too. Good stuff and indeed 1000 times better to work with than the Tefzel stuff.

Hans


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