Wiring through firewall

[93SVT5.0TT]

Hey all,

Just wondering what the popular route is for getting wiring through the firewall. I imagine most/some people have their ECU inside the cab and have to pass 40+ wires through the firewall. Do most of you use a bulkhead (mil-spec, Duetsch, something less $$$?) or run the wiring through and seal the hole? Pros and cons of living with either decision?

Thanks,

Tristan

[Dynoroom]

I have done it a couple of different ways depending on the amount of wires you are working with.

The simplest is drill the hole, run the wires, fill the hole with fire putty from the hardware store.

You can also drill a slightly larger hole, run the wires through a short piece of fire sleeve then push both through the hole and it will crimp down on the wires make a tight fireproof seal.

The next method uses "Cannon" connectors (see pictures) which is a plastic connector not nearly as expensive as the mil-spec part.

I'm sure others will also provide options.

[Milwaukee Midget]

That's slick, Michael.

Switchcraft makes some dynamite multi-pin connectors, many of which are military grade.

http://www.switchcraft.com/Category_Wide.aspx?Parent=15

There is a huge advantage to going this route in that you can create your under-the-hood wiring harness on a bench with soldered connections without having to install connectors while leaning over a fender.

Additionally, you can then create another pigtail, remove the ECU, and bring it along for dyno work, so your tune doesn't have to be virtually recreated.

All the pins are numbered, and with patience, you can create a bulletproof harness.

I'll be upgrading to EFI, and Michael's method will be the way I'll be doing it.

[93SVT5.0TT]

Thanks for the input guys.

Where do you buy Cannon from? I haven't been able to find anything helpful online for them. But yeah, this is basically what I had in mind, but using the Deutsch HDP20 series connectors.

I think I've talked myself out the epoxy/hole method, just for maintenance purposes... how many times have you guys had to add/remove a wire here or there? 

Unfortunately the Switchcraft ones only have up to 31 pins, so I would need 3 of them. Good prices though.

Any other good methods anyone?

[Peter Jack]

If you're in Calgary in the next while stop into B&E Electronics, 444 Manitou Road SE or check out their website. I think you may find what you're looking for under connectors, military on their site. Their counter guys are knowledgeable and really good at helping out. The drawback to doing this is once you get into the store your wallet and credit card tend to scream a little.  

Pete

[manta22]

In my experience it is not a good idea to put everything into one connector. Like wiring everything with one color wire-- you can do it but it isn't a good idea.

I'd suggest breaking the wiring up into groups that are more or less "subsystems"-- things that can operate without relying on a power or ground wire from another connector. "Cannon" plug is a reference to the old WW II connectors produced by Cannon Electric that pretty well became standard through the Korean War era. They aren't bad connectors but the fine thread on the coupling ring is a PITA-- lots of turns to tighten & loosen plus it is too easy to get it cross- threaded.

Deutsch makes good connectors but so do others. Check the surplus market for mating pairs. Another caution-- do not use more than one of any connector type; Murphy's Law says eventually they will be accidentally connected wrong. Some types of connectors need expensive tools to insert the pins, so be aware.

Check the pin & wire size with regard to the current- carrying ability. The convention is that the hot wires are female; this minimizes the chance of shorting an exposed pin. The connector mounting flange is usually placed on the side of the panel that the mating cable connector mates with.

Regards, Neil  Tucson, AZ

[Milwaukee Midget]

One additional thought - Just about any military connector is going to offer a higher degree of fire protection through the firewall than civilian or OEM auto applications.  

. . .how many times have you guys had to add/remove a wire here or there?  

Every time I put the car back together.  All the more reason to go with more than one connector, and use connectors with more pins than you need.  

Because you will eventually need them.

[bearingburner]

We have our ECU in an surplus ammunition box and have the wires fes through a amphenol connector.I think there are 30+ terminals. We used an junkyard rubber firewall fitting to feed wires to and from the relay box also a surplus ammunition box,

[NathanStewart]

Why are you needing to pass 60-90+ wires through your firewall? What engine are you running? Fwiw I use a very inexpensive 47 pin delphi connector that's a deutsch equivalent (do some looking around, you'll find it - can't give away all my secrets  )and I can support most standard v8s with full I/O.

[93SVT5.0TT]

If you're in Calgary in the next while stop into B&E Electronics, 444 Manitou Road SE or check out their website. I think you may find what you're looking for under connectors, military on their site. Their counter guys are knowledgeable and really good at helping out. The drawback to doing this is once you get into the store your wallet and credit card tend to scream a little. 

Pete

Thanks Pete, I think my brother deals with them a bit. 

Neil,
I'm planning on using two differently sized connectors so they can't be mixed up. I have a line on some good labelled mil spec wire from some new never used harnesses, so if that works I may not need to label anything.. Thanks for the advice sir.

One additional thought - Just about any military connector is going to offer a higher degree of fire protection through the firewall than civilian or OEM auto applications. 

True, but how long does it take to burn through a connector? (legit question)

Why are you needing to pass 60-90+ wires through your firewall? What engine are you running? Fwiw I use a very inexpensive 47 pin delphi connector that's a deutsch equivalent (do some looking around, you'll find it - can't give away all my secrets  )and I can support most standard v8s with full I/O.

Running a twin turbo 5.0 v8 with a Performance Electronics PE3 ECU. And need room for spares and some bits of chassis wiring. Thanks for the tip on the Delphi stuff. 

[Milwaukee Midget]

One additional thought - Just about any military connector is going to offer a higher degree of fire protection through the firewall than civilian or OEM auto applications. 

True, but how long does it take to burn through a connector? (legit question)

A good question, indeed.  Truthful answer?  I don't know - it depends on what's burning under the hood.

It's not as likely that the heat from a short circuit will cause the connector to malfunction as it is the heat from a burning engine.

And my legit response would be I don't want to be in the car when the test begins.

 

[93SVT5.0TT]

One additional thought - Just about any military connector is going to offer a higher degree of fire protection through the firewall than civilian or OEM auto applications. 

True, but how long does it take to burn through a connector? (legit question)

A good question, indeed.  Truthful answer?  I don't know - it depends on what's burning under the hood.

It's not as likely that the heat from a short circuit will cause the connector to malfunction as it is the heat from a burning engine.

And my legit response would be I don't want to be in the car when the test begins.

 

yeah same here... 

[manta22]

Plastic bulkhead connectors would burn through fairly fast; MIL-SPEC metal-shell connectors would be far more fire- resistant.

Regards, Neil  Tucson, AZ

[Glen]

On the two vesco streamliners we run all wire through fire sleeve in all locations and through the fire wall and in the cockpit. I't to major of a job to replace wires anywhere on the cars.