Great work Shoeless. The great stock of tools you have make everything a magnitude easier. A tip on long runs of + - signal wiring like Canbus etc is to pull an arms length longer of wire than you think you’ll need, clamp the ends in your vice, and the other ends in your electric drill. Walk back to pick up the slack and then twist away (for “twisted pair” noise rejection) and then trim the ends. Also get an armful of plastic cable wrap at Harbor Freight! Also those cheap “helping hands” stands with the alligator clips make holding all your soldering work easier still.
Thank you for the kind words HardRocker and you make some excellent points, enough so its worth going into some more detail. High quality proper tools definitely go with out saying. When you are creating a mil-spec harness there really is no room to cheap out, although I have found some good budget tools that I will be trying along the way. One specific example of this is the tool I will use to crimp the pins on my Molex MX123 connectors (those identical to the LS computers as Shane pointed out to me in an earlier post). The recommended tool is a Molex 63811-4200 that retails for around $360, while the Molex 63811-1000 will do the same crimp but sells for about $50. If I was going to build more than one of these, I could likely justify the $360 pair, but I'm only building my own right now so I'll try the $50 pair on some test wire first.
CAN Bus cable is another great topic to discuss. You are absolutely right on pulling more wire off the spool before you twist and then cut to length. Another approach is twist a really long run and wrap it around a spool for later so you can cut off as much as you need, when you need it. Now on to the question of how many twists per lay length is ideal. Well, it varies by the diameter of wire you are going to use, although it is a broad range that easily overlaps for different wire diameter size. You should target a lay length of between 8-16 times the diameter of the wire, and lay length is the distance down the length of the wire as it makes one revolution. When you go to actually twist it with a drill, to help it from fraying apart and relieve a little tension, you can actually over twist it and then back the drill the other way to untwist it a little until you get the proper lay length. This will give you a very nice and clean CAN bus network that will work as intended.
Oh yea, and you mine as well grab a bag of about 1,000 small zip ties to us for your entire harness building project as they will be used as a consumable item throughout the whole project
I bet I have gone through a 1000 wire ties, use them to hold ting in place and cut off later as well as final position and to cleans up wiring. They do come in really handy when build by yourself and you need to hold thing in place temporarily. Have them in all different sizes and would not have done some of the thing I have done without them or a second pair of hands...
Same here....the tiny 4" cable ties....I use a TON of those.....most of them being temporary, only to be cut off and discarded.
Shane Vacek
VRaptor SpeedWorks, LLC www.vraptorspeedworks.com
Turn-key GTM, SL-C & Ultima GTR Built to Your Specs!
Offering a full line of GTM Upgrades and Custom Parts
Got a new toy today in the mail. This label maker will print directly on heat shrink tubing and will be used to identify the branches on the engine wiring harness as well as help me label all the other wiring in the GTM to keep it all nice and neat. Love me some new toys
Just a heads up...we make the heat shrink with the label on it, put it in place, shrink it down, then add a protective cover of clear heat shrink so the lettering can never be rubbed off. It just makes the label that much more durable.
Now on to the question of how many twists per lay length is ideal. Well, it varies by the diameter of wire you are going to use, although it is a broad range that easily overlaps for different wire diameter size. You should target a lay length of between 8-16 times the diameter of the wire, and lay length is the distance down the length of the wire as it makes one revolution. When you go to actually twist it with a drill, to help it from fraying apart and relieve a little tension, you can actually over twist it and then back the drill the other way to untwist it a little until you get the proper lay length. This will give you a very nice and clean CAN bus network that will work as intended.
Indeed, especially for high RF environments. These days for car stuff I usually go with what looks correct having pulled many spools of twisted pair back in the day.
btw, that labler is super cool. And Crash, nice to know about the heat shrink you have, I'll take a look.
Just a heads up...we make the heat shrink with the label on it, put it in place, shrink it down, then add a protective cover of clear heat shrink so the lettering can never be rubbed off. It just makes the label that much more durable.
Absolutely. Slide a piece of Raychem RT-375 (Clear Heat Shrink) over the label and shrink that down for a very durable label.
I should have done the same thing, I used a normal label printer and wrapped it around the wires but the method you used is much better. Thanks for posting your methods and travel into the electronic wiring world. Learning new things is always good, even though it is to late for my current build as beeman stated still good to know for the next one....
This unit is very reasonably priced for its functionality.
I've got it charged up (came with a rechargeable battery and charger plug) and started to familiarize myself with the settings. It will print on 1/4", 3/8", 1/2", and 3/4" diameter tape and if I remember correctly, the roles of heat shrink tubes are a 2:1 shrink ratio. I've got some cartridges of 1/4" that will hopefully be delivered tomorrow and I'll throw up a little example of what a finished product will look like.
And Crash, nice to know about the heat shrink you have, I'll take a look.
We actually don't sell the heat shrink. I was just relating what we do on our harnesses. Don't mean to sound like a broken record, or a paid pitch man, but we get our supplies from www.prowireusa.com.
Crash is right, I have found prowire to beat most prices I have found on Deutsch AS (Auto Sports) connectors and several other products that are required to build this level of harness.
I got some of the heat shrink tubing in so I wanted to run a few tests and see what would work or not. My goal was to mimic the steering wheel button switches that I'll be cleaning up nicely and connecting with a Deutsch AS connector to the clock spring beeman hooked me up with.
On a side note, I only need 11 wires, but the closest Deutsch AS connector I could find is a 19 position 20 ga plug/receptacle combo. There may be other AS level plugs out there, but then you have to think of a whole suite of tools just to use them. So I may just stick with the 20 ga connectors I'll be using in nearly every area of the engine harness to keep tooling costs low.
Materials Used:
- Heat Gun
- 4 x sections of 20 GA Tefzel wire
- DR-25 Heat Shrink Tubing (Note US version has yellow lettering and UK version has white lettering) There is no difference, and I got a killer deal on the UK version so that's what I got.
- Label Maker w/ 1/4" Dia. shrink tubing
- Raychem RT-375 Clear Heatshrink
1. First measure the cross section of the bundle of wires you are looking to put heat shrink on (4 x 20ga Tefzel wires is ~ .100") and then choose which size DR-25 is appropriate.
2. DR-25 has a 2:1 shrink ratio and you want to chose the diameter that will tightly grip the bundle after being recovered. The closest that is available that I have is 1/4", so I'll have to pick up some 1/8" or 3/16" for when I do this for real on the switches.
3. I recovered the DR-25 onto the bundle of 4 wires. Note DR-25 has a minimum full recovering temperature of 347 deg F so you want to choose a temp just over that to help it recover nicely. The Dewalt heat gun is perfect as you can choose temps in 50 increments up to 500 deg F. so I chose 400 deg F.
4. Then I tested out 3 of the smallest font sizes on the new Rhino 5200 (XXS, XS, and S). Worth noting is that the Rhino 5200, as well as most other label makers, will leave a good bit of "waste" tubing that you have to trim back. If you can print out a whole bunch of labels with 3-4 spaces between them, you will save more of the ribbon tubing.
I ran into issues here with the 1/4" labeled shrink tubing being too small to slide over my recovered DR-25, so in order to continue with my demo I chose to install the test strips onto a piece of 12 GA Tefzel. This will be perfectly representative of how I will use this to label all other connections on the car, so not all is lost.
5. I then recovered the labels over the 12 ga Tefzel wire with the largest in the center, which I think it what I would go with on this size. Worth noting is that you will want to pick a font size that will work for every situation so you have only one font size throughout the whole car just to look more sharp.
6. Then chose the smallest size of Raychem RT-375 that I could slide over the label and recovered that with the heat gun. This clear heat shrink is what crash mentioned earlier. RT-375 is also a 2:1 shrink ratio and recovered nicely with 400 deg F.
We now have a representative sample of what a finished product will look like.
Sean, that looks really good and since you can print on shrink tubing will stay on wires better than the way I did it. I had a brother label maker and printed labels but can only flag the label on the wiring. But it did kinda work but they can move sometimes. Don't need it on this build as all wiring done but would sure use your method if building another car.
Thanks James!! This approach will give me a very tidy and long lasting label that will stay put for the long run.
I’ll be ordering up more sizes here soon so I can dial in the perfect size for my steering wheel button plate. This thing is going to turn out awesome!!!!
I spent some more time working on the steering wheel button plate over the weekend. This could either fall in my build post or here on the wiring post, I figured I would post here.
I had to find either a shrink moldable boot that would fit the 4 momentary push buttons or a combination of the heat shrink I had on hand. After a number of samples on a scrap button, I landed on a combination of 2 sizes of Raychem ATUM. This is a 4:1 heat shrinkable tubing that is glue lined and would be appropriate to seal everything up nicely. I started with the DR-25 tubing on the wiring and then worked towards the switches with two different sizes of the ATUM.
I had to then lay out where the wiring would be routed around the Momo adapter. This actually had to be done before the above so I could use the proper length of DR-25 on the wiring itself. Then had to think a few steps ahead of where the last junction would be before feeding into the Deutsch AS connector.
Then worked on bundling, splicing, and sheathing the wires for the 12 position dial switches. This was a PITA as I had to move all the heat shrink to one side, splice the wires, and then shrink the Raychem SCL over each of the spliced joints. Once all the joints were covered I slid one last piece of SCL over all the splices to seal them up perfectly. Add a zip tie to hold the two branches that come out to the right of the SCL and the joint is now properly strain relieved.
I'm now to the point that I can trim down all the wiring, install the last pieces of heat shrink and install the pins. I checked my tooling and damn if I didn't pick up the wrong positioner for the AF8 crimp tool. I made a call to ProWire as it said it was out of stock and glad I did. They are putting an order together and hadn't added these positioners to their order. They should have one in stock for me in about a week so the rest of this will have to wait. In the meantime, I did a final fit check on the Momo adapter and steering wheel and then performed a continuity check on all the circuits.
All told there is a total of 22 wires that are spliced down to 11 to go through the clock spring that beeman hooked me up with.
That's the coolest steering wheel I've ever seen on these forums. It puts a lot of Ferrari wheels to shame.
Thanks for the compliments and kind words!!! I put a ton of thought and effort into this and glad it turning out the way I saw it in my head months ago when I first started.
I would have thought you would have seen these? Any reason you did not go with these?
Hey crash,
I reviewed those as well as the 222D921 and the 222K series boots. Since my momentary buttons were so long, not the typical steering wheel button plate buttons, I didn't like the "P" measurement for any of the offerings. Also each of these boots has a lip that would need to be trimmed off as there is no groove on my switches. That part is doable, just didn't like the length of the small opening leg. Looking back at my pics you can see as soon as the wires exit the back of the switch they loop almost 180 deg back toward the CF plate. Any of the shrink moldable boots I looked at just had a leg that was too long for my liking. Could I have trimmed the long leg of the 222K921 to make it work or trimmed the "J0" length on the 222K or the 222D you shared? Sure, but I would still have to add a piece of ATUM or SCL to cover the potted area of the momentary switches for a nice look. My approach just happened to work out for me and achieve the look and sealing I was going for.
I agree that what you did looks pretty good. I think I might have gone with the 90 degree boots for the rotary switches though...except they are FREAKING EXPENSIVE! I thought maybe that's why you didn't use them. It's why I didn't use them when building our steering wheels.
I agree that what you did looks pretty good. I think I might have gone with the 90 degree boots for the rotary switches though...except they are FREAKING EXPENSIVE! I thought maybe that's why you didn't use them. It's why I didn't use them when building our steering wheels.
LOL that is a great point, this whole venture it STUPID EXPENSIVE!!!! I can hardly believe how much it cost me to get Deutsch AS connectors for my whole suite of engine sensors and coils. But I got some invention money from work for 6 patents I filed last year, so that covered the expense of all the connectors. In the end, I would not recommend this approach for many people. For myself, I simply love the idea of learning something new and I like the idea of building a world class engine harness. It will be a serious work of art when completed.
This is one of the things I think most people do not understand about when one steps up to a racing or motorsports environment. The conditions can be brutal. Whether it is heat or water intrusion with wiring, or durability with oil lines, or just flat out stress on suspension components, most items need to be either custom made, OEM improved, or brought in from the aircraft/aerospace lines, and that gets expensive very quickly. Just to run the AN lines throughout a race car runs in the $10,000 neighborhood. Wiring? Easily $5k. Electronics? $10-15K. Point is, sometimes it is easy to get into the mindset of "eah, what's another $100 on boots for the steering wheel". Do that 100 times, which can easily happen during a build, and it gets into real money real quick.
Agree, does not take long and you have a lot of cash in the upgrading parts. But worth it when build your master piece or at least I keep convincing myself of that....... makes those expensive PO's easier to swallow !
So i've gotten in a couple big orders of stuff to start building my harness for the engine, but the first step for me is to create pig tails for all the sensors and coils. So for the mean time, I'm going to set the steering wheel aside. When I get a few parts potted and RT125 drying, I'm sure I'll pick it up and finish it off. Plus I want to get some more practice on shrinking the large Raychem boots. There is a technique and I need some practice to not screw it up.
So I'd like to share the steps of installing a Deutsch Auto-Sports connector to a sensor, specifically the Cam sensor. To start out with I've already soldered and potted 3 conductor shielded wire to the Cam sensor. Normally I would put a piece of Raychem SCL or ATUM over the sensor and potted area to add strain relief, but the flange of the sensor would not allow it.
Here are most of the things I used today for the job.
The first step is to remove the casing on the shielded cable to expose the shielding. From here you trim back all but about .250" of the shielding in order to use a solder splice to connect a separate conductor in order to pass the shielding through the connector.
Once the shielding is slide back over the insulator of the wiring, slide the solder splice over the shielding, insert the extra conductor, and apply about 950 deg F to the solder splice. Each splice has a ring of solder that has a red coloring on it and once the red is all gone, the solder is done melting.
Each of the four wires are now stripped, socket installed, and crimped in place. In addition you add a loop for strain relief.
At this point you can now use the insertion tool to install each conductor. In this particular free socket, there are 6 positions for 20 ga wire and I'm using four. In order to fully sealy this connector, you still install the sockets in the two blank position, and then install a red plug behind it. You can see one of the two in this pic.
In order to protect the wire and make this serviceable later down the road, just in case, you add some Kapton tape over the wires and a small portion of the socket. Also notice I had to put a piece of Raychem SCL to increase the diameter of the wire so the small end of the shrink moldable boot would seal against it. Note the fact that the shrink boot is much larger in its unrecovered state, so I don't have to install it over the wire before intalling the socket.
Before shrinking the boot, you lay down a small bead of Resintech RT125 in the grove of the Socket. Then working with the heat gun applying even heat to shrink the end over the Socket. Then lay down a bead of RT125 on the other end and shrink down that side of the boot.
Nice write up, fun to learn about that high end stuff. I can't believe the boot shrank that much, definitely not consumer level stuff...
Thanks Dave!!! I'm really enjoying this process of creating a high end wiring harness and extending it to each sensor. Pretty wild on that shrink moldable boot, right? There is definitely a technique on shrinking them properly and I hope to get better as I do more, but this first one turned out pretty nice. One more thing to add is this boot (PN: 202K132) can actually be trimmed back to the next moldable lip. There are two lips on this boot and I didn't realize the final length as the data sheet was a little ambiguous. On my next one, I'll try to trim the boot back to the next lip, as I don't need it this long to cover the wires underneath.
Did you stripe your wires or did you buy them striped? If you striped them, what product did you use? I have used a Sharpie based product previously and it didn't work well. The Tefzel sheathing caused it to not stay on/dry.
Did you stripe your wires or did you buy them striped? If you striped them, what product did you use? I have used a Sharpie based product previously and it didn't work well. The Tefzel sheathing caused it to not stay on/dry.
I’ve picked up several rolls of the 20 ga Tefzel for the whole harness, as well as several other 10-20 foot sections of various gauges for the power distribution side.
I’m using the Ergo Elite (grey handle strippers in the first pic on the right) with the wire stop to strip my smaller gauge Tefzel and an Ideal Stripmaster for 10, 12, and 14 ga wire. On the Ergo Elite with the wire stop you can do test pieces and set it to the perfect strip length for the pins and sockets for the AS connectors.
Here the actual link to the kit I picked up. Pro tip, if you can wait till Black Friday, they do a once a year big sale. There were some exclusions last year, but that’s when I picked this kit up.
Um….I was asking about STRIPEING not stripping. Trust me, I know much about strippers!
HAHA my bad, I figured you did, shared anyways. STRIPEING wise I guess you are asking about the white/blue, white/orange from the shielded wire I used on this sensor. These came striped from Prowire.
Have you tried something like the following Ident. Kit with heat shrink colored rings? I've done a few wires so far, the ones on the steering wheel button plate (Bottom of last pic in Post #57). I've found you better shrink them with enough heat or they can slide off.
My main engine harness will only have 5 colors and mostly it will be white with these ID rings so I can keep track of the wires.
Good to know about the already striped stuff from ProWire. The last time I bought Tefzel it was from Aircraft Spruce in bulk on sale and all they had was white. I also bought their suggested striping kit with the Sharpie method, but I was not happy with that. Guess I'll have to go talk to Nick.
Nothing too earth shattering to share, but I finished up the 2 x knock sensor pig tails. Probably a bunch of different ways to do this to minimize the sealed joints, but this is what I came up with for what I had on hand. On the knock sensor side I took a razor and cut off the alignment and lock features for the male plug that would normally attach here and then sanded down to scuff up the surface for the Raychem SCL to adhere to. I used a couple smaller diameter pieces as its a 3:1 shrink rate to ensure I would have a nice sealed joint. It also spreads out the load from the wire to the knock sensor body. Again, probably a better more expensive solution, but this is going to work for me. Similar on the boot side. The smaller version of the boots I used on the Cam sensor above were used here for the 3 position Deutsch AS connector. Add a little SCL and this is a perfect setup for me.
Next will probably be the Crank sensor. I may make a longer pig tail as this is hidden up behind the starter and hard for me to access since I put in the additional heat shield. Probably target the length to meet up next to the knock sensor plug and ultimately the main wiring harness.
It was a slow work day with a good bit of the office furloughed, so I broke out some wire and did some test branches on concentric twisting. The idea was a build a few sections to see how they lay would look, how many circuits I could get in one branch, and just get some practice.
The idea is that you start a core that you then twist in alternating directions subsequent layers to give a very flexible compact harness at the end of the day. the down side is this approach is eating up a ton of time with all the documentation required to get it right, but in the end this will be bad a$$.
There is a general rule of thumb that you don't want more the 5 "cables" in the core, so I tried a core of 1 x 3 wire shielded cable followed by layer one of 1 x twisted pair CAN, 4 x 2 wire shielded cable, and 1 x 3 wire shielded cable, all 20 ga. The second layer consisted of 26 x 20 ga wires and this is where I stopped. From here the next layer would have taken 32 x 20 ga wires, but I have 41 wires remaining and would drive another layer of 38 wires just to take up the 9 wires I have left. I would then be left with 29 filler wires just to round out that last layer. Not idea, so its time to take it all apart and try another approach.
Holy Sh*t.......I have a lot of patience......but that ^^^^ would be pushing it. I think I'd need a lot of beer.
Shane Vacek
VRaptor SpeedWorks, LLC www.vraptorspeedworks.com
Turn-key GTM, SL-C & Ultima GTR Built to Your Specs!
Offering a full line of GTM Upgrades and Custom Parts
Holy Sh*t.......I have a lot of patience......but that ^^^^ would be pushing it. I think I'd need a lot of beer.
HAHA Some days I question my decision to learn this approach and spending all the time and money doing it, but I am really enjoying learning the process and can't wait to get to the point of starting to build the real harness. For now its just test after test until I get the branches planned out properly.
What's really screwing with my plan is items like my throttle body that connect to the ECU through both of the two master connections. This is leading me down the path of needing to combine approximately 130 wires into one branch right after coming out of the ECU. It will be one hell of a branch point at the very first part of the harness, so I need to get it right.
Shane is right you must have a lot of patience for sure, unbelievable, it looks fantastic, know I did not do that good a job. Keep up the post and work it is fascinating to see your progress and how to build a professional wire harness.
Thanks: 
Likes: 
Originally Posted by HardRocker
Reply With Quote
