Just finshed the fi harness. Thanks to the board members who helped me find the factory connectors

Where did you find the connectors? And new rubber boots. I need a bunch of new boots. Looks good!

That looks great! Please tell us all about your technique and where the supplies are from.
Will the rest of the FI system be able to keep up with that fast yellow harness?

I await your answer with baited breasts. My harness is a flexible and supple as great grandpa's back. AND it's not even yellow!!

Eagerly waiting to find out the source of those connectors and boots.

-Tony

The silence here is deafening.

Me thinks we no gonna hear where to goodies came from.

I am reluctant to because they could be the source of much controversy. Plus I don't know how many more I can get. I can tell you they came from Germany They boots were recycled from old harnesses.

So you come here to taunt us!! <_<

You first tell us


And then you say you can't tell us. I'm only upset because I'm VERY jealous.

Maybe if the demand is high enough I could see about maybe having some of these manufactured by my father-in-law who is a injection molder/die maker. He's made some electrical connectors before, and can do rubber parts as well.

-Tony

I am damned if I do Damned if I don't.

I bought some boots a few years ago from Automobile Atlanta. The came in a bag with a Mercedes Benz part #. Early Volvos also use the same boots.

Cut Dylan a break guys, pretty sure he was told by a supplier in confidence where to source the parts, with the condition that he not divulge the source. The said supplier most likely spent major time, research and cash to find this source. Dylan is most likely now sorry he posted this.

Also this stuff is no good to you without the proper tools. Dylan works for an aviation company and that’s why he could do this job.

No hard feelings. I and others were just excited at the prospect of finding a source of these. It seems though that the supply must be very small and knowledge of where to get them is obviously proprietary to someone who can make money from that information, which as you've said took a lot of effort to obtain.

I'm sure there are more than a few here (like myself) who also work at aerospace companies and have access to the proper crimping tools, shrink tubing, teflon wire, maybe silicone wire, epoxies and the like that are necessary to build truly durable wiring harnesses.


-Tony

p.s. F4i, the harness looks awesome!!

No hard feelings here. And thanks for the compliments. I posted here before about getting connectors. The reply that netted me the parts was made privately. I fully respect other peoples privacy. If they wanted it public they would have made it so. There is a board member that makes harnesses. I am not looking to compete with them either. I am sure there are others that are more than capable of fabricating these harnesses. I did use mil spec wire etc. however it could be done other ways. Good luck guys.


PS thanks Mark H GO FLAMES GO

Jeff Bowlsby rebuilds and repairs harnesses, in addition to selling new ones. The materials he uses are either OEM or are superior. If you have a harness that needs a new connector or boot, try contacting him at bowlsby@aol.com

What material did you use for the sheath?

Bowlsby will not sell just parts, they only come with his services. I have heard that his work is excellent however. I used a high quality heatshrink as a sheath.

Is the heatshrink still flexible even after it's "shrunk"?

Most heatshrink I have used gets hard to bend after it cools off. Maybe certain kinds don't?

It stays very pliable. It boasts an operating temp. of -55 to 125 deg. c. I didn't even know that until you asked.

Nice harness, but I thougt orange was faster! At anyrate, check old VW FI cars, they have same kinds of connectors, fast backs, squarebacks, busses, are a bit more common than 914s at wreckers. The rubber boots on a watercooled vangon will even work on some connectors, and they are at least on or two decades newer than the squarebacks, so the rubber will not be as rotted.

One thing I noted on many harnesses is that some parts of the harness over the engine are much more brittle, and blackened than others, seems it has to do with proximity to the hot engine case. originally the harness was routed tightly aginst the case were it passes around the rear (flywheel side of engine, and forward towards the dizzie). I have rerouted the harness so it stands off the hotter engine case, and now rests as much as possible on the cooler cooling tin pieces. I think this will add some life to the harness, new or old.

I have been thinking of using nylon expandable mesh to shield my new wiring harness. I wonder how well it would work?

mesh is not the best material for in the engine bay. You really want to protect the wires from oils, and engine cleaning solutions, and mesh will not do that, also mesh may not give as much temp protection.

After pulling apart several harnesses, one thing became clear to me, if the stock wire was exposed, its insulation was more brittle, and stained, pull back the harness sheath, and the same wire further back was in better condition. A mesh just won't give the same protection as a solid sheath. I think it is mainly an oil / chemical contamination thing. Also the mesh, when it gets dirty, will be a pain to keep pretty looking, verses a smooth sheath.

Of course if you use the higher quality teflon insulated wire, chemical deterioration will be less of a problem than if using vinyl, or rubber insulated wire, but still the issue of dirt and oil looking ugly trapped in all that expandable webbing remains.

I agree that the nylon webbing is not the best material for an engine bay. Heat shrink tubing is good, though the question about how it ages with temperature cycling warrants an investigation into the different kinds available. An alternative to shrink tubing could be some kind of high temp (silicone or teflon) sheathing that doesn't shrink, but provides similar protection.

Another important thing to keep in mind with dirt and chemicals is galvanic corrosion at the interface of dissimilar metals, such as silver plated copper (in the case of milspec teflon wire) and the brass, copper, or nickel plated lugs that comprise the connectors. At a minimum these should be covered by shrink tubing to prevent chemicals from intruding and forming rectifiers.

Keep in mind that strain reflief is important at the connector housings. The harness itself should be tied down in several spots so that the strain is distributed over the wire, rather than at crimped joints.

If you want to get really nuts about it, you could actually pot the connectors with some high performance epoxy. This helps strain relief, but makes it basically impossible to do future repairs.

Oh, and use only teflon wire. It's very expensive and hard to find but ebay can be a good source of it. You can get away with using a slightly smaller guage of teflon wire than regular copper wire since the resistance per length is lower, and the insulation will sustain higher temperatures. For maximum flexibility you can parallel multiple thin strands, though the current handling doesn't add to be quite as high as the number of wires in the bundle...


-Tony

Well said. Although you can go with a smaller guage of wire with the teflon I advise against it. The thinner insulation makes it difficult to crimp to the open barrel style terminal. You could solder the terminals after crimping to aid in strength,contact and corrosion prevention. M22759 mil spec wire is a good choice IMHO. Heat really does not touch it. You can obtain this stuff at your local aircraft parts suppliers. Companys Like API or Aviall carry it. Vibration is hard on things as well. Securing your harness well in cool locations (as said above) are going to help it live a long life.