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Wiring/Firewall Penetrations....

Reflex

Well Known Member
Will likely hang my engine in the next couple of days on my -14. I'm wondering if the two holes/passthroughs provided by Vans are enough to get all the wires through the firewall? Also anything I forgot?

I show a total of 27 items that need to be put through:

 
Just a few >

For starters, at least 4 - 20AWG and maybe 2 - 20AWG shielded, at least 12" FFW and 24" behind the FW for any future stuff. And whatever else you think might reveal itself in the future.

And, consider that for the Throttle/Mix/Prop pass-throughs may be better placed than where Van's allows for them. May need some of those eye-ball swivel pass-throughs or whatever you're comfortable with.
 
With that list, you will have plenty space with the two provided access holes. I would not drill any other or enlarge unless you really have many other things running thru.
 
Pass through

If you are in need of an Avery SS firewall pass through, I have one that I did not use on my -10.

Make you a deal on it...
 
How many you want?
.
 

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Many thanks for the replies. Was just wondering if the two holes Van's provided was enough.

Nice looking stuff Dan, if I need to add, I'll go that direction.
 
Can I add to this?

I'm at the exact same place. Just hung the engine, and now I find myself in a place I know almost nothing about. Mine is an 8, so if that makes a difference, I apologize for piling on.

I looked through this list (thank you, by the way!) and added three more things, Cabin Heat control, Oil Cooler Valve and Fuel Line. You repeated CHT Cyl 1, so by my count you had 26. I now have 29 penetrations.

In my mind, I have 4 categories:
Mechanical linkages: throttle, mixture, prop, Cabin heat, Oil cooler shutter and alternate air.
Fluid: fuel.
Power lines: Battery, E-mag 1, E-mag 2, Alt 1, Alt 2, Alt 1 Shunt, Alt 2 shunt and Starter.
Sensor lines: Oil Press, Oil Temp, Fuel Flow, Fuel Press, MAP, Tach, EGT 1, 2, 3, 4, and CHT 1, 2, 3, 4.

Fuel is by itself.
Since Power and Sensor do not mix well, that seems like two more penetrations.
Mechanical? I see the Van's holes for throttle/mixture and prop, so that's making me think the mechanical connections have their own penetration, or can they be grouped as well?

Am I kinda, sorta on the right track here?
 
Six holes total

I have two 7/8” holes for every wire except big 6AWG main bus wire. Then, one for throttle and mixture, one for cowl flap and one for alt air and prop. The alt air prop is a double eyeball as is the throttle mixture.
 
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Will likely hang my engine in the next couple of days on my -14. I'm wondering if the two holes/passthroughs provided by Vans are enough to get all the wires through the firewall? Also anything I forgot?

I show a total of 27 items that need to be put through:


This is not an EXP119, correct? The EXP FWF kit should come with a third, eyeball-style passthrough for engine control cables. It gets installed just below the existing one on the right side.
 
Correct, this is not an EXP199. Just a plain old IO-390 Thunderbolt. You might catch Clay's post above...looks like I had one too many lines as I put in the CHT for Cyl 1 twice. Total penetrations are 26. At this point, I appear to have enough room but haven't finished all the wiring yet.

Yes, my understanding is that the EXP-119 needs a third penetration for the throttle cable.
 
Maybe it's just me, but I can't get happy with electrical wiring in the same penetration tube as a Bowden cable. It's like putting a hacksaw blade in your underwear...might chafe a little.
 
Maybe it's just me, but I can't get happy with electrical wiring in the same penetration tube as a Bowden cable. It's like putting a hacksaw blade in your underwear...might chafe a little.

Noted. I may put another penetration in the firewall for the cables. Certainly frustrating when you build as per the manual only to find out it's not the best way. As a first time builder I tend to rely on what's in the plans and have found on multiple instances that what's in the plans will work, but it may not be the best way to do something.

Gonna be a pain to install that additional penetration with the engine already mounted and Fiberfrax on the firewall, but if that's best....that's what I'll do.

Thanks for the tip.
 
Firewall penetration

Noted. I may put another penetration in the firewall for the cables. Certainly frustrating when you build as per the manual only to find out it's not the best way. As a first time builder I tend to rely on what's in the plans and have found on multiple instances that what's in the plans will work, but it may not be the best way to do something.

Gonna be a pain to install that additional penetration with the engine already mounted and Fiberfrax on the firewall, but if that's best....that's what I'll do.

Thanks for the tip.

I had to add one recently. Trim the foil first. I used a dremel with a burr. Drill bits will shred the foil.
 
I had to add one recently. Trim the foil first. I used a dremel with a burr. Drill bits will shred the foil.

No they won't. Lord knows, I've drilled hundreds in 0.002" foil. Anyway, a tubular penetration with a base plate can go on over the top of the foil and fiberfrax. It just becomes a gasket.

Here are some over and under.
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Foil

No they won't. Lord knows, I've drilled hundreds in 0.002" foil. Anyway, a tubular penetration with a base plate can go on over the top of the foil and fiberfrax. It just becomes a gasket.

Here are some over and under.
.

I stand corrected.
 
My current pass through items list has 34 electrical items on it. I currently have 2 1" pass throughs, but I purchased a third which I plan to mount. I do have a couple of misc. temp sensor wires I added.

The thing you have to realize is some/many of the items are more than one wire. EGT/CHT are 2 AWG 20 wires for example. Some sensors are 3 wires.
I used AWG 20 for all wires that go to the engine for my firewall mounted items I used AWG 22. You can follow whatever you feel comfortable with.
 
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