Archive for March, 2014

Hot Rod, Street Rod, Rat Rod, Custom Car Electrical Wiring Made Easy – Part 1: The Relay

Thursday, March 20th, 2014

Hot Rod, Street Rod, Rat Rod, Custom Car Electrical Wiring Made Easy

Part 1: The Relay

Everyone pays loads of attention to paint, tires, wheels, engine, chrome, interiors, but when it comes to wiring your dream machine, there is a hidden monster lurking inside your car. Wiring your hot rod, street rod, rat rod, custom car, or whatever else you would like to call it, does not need to be difficult but does need to be completed correctly. Sure, there are loads of universal wiring kits available that you can order and use. Some of the companies that manufacture universal automotive wiring kits or harnesses are from: Painless Performance, EZ2wire, Rebel Wire, Speedway Motors, American Autowire, and Ron Francis only to name only a few. These universal wiring kits are fine, as they include most of what you need to wire your hot rod. They are simple and safe to use and come with easy to follow instructions. It is so simple that many of these manufactures will label the purpose of each wire. The big problem is if you wish to be a bit different, and wire your hot rod placing, switches, fuse panels, and etc….. in hidden in odd places, then these kits would not work too well. Not to mention, you can buy most of the individual parts to wire your street rod much cheaper than the average universal wiring kit. By wiring your custom car yourself, you can route wires within the car as you see fit. This is what I exactly did on the 1929 Ford roadster hot rod.
This will be the first of many parts on how to wire your hot rod safely yourself, with easy to follow instructions, circuit diagrams, and how to videos. I will even include testing of the various electrical components in the hot rod to determine the correct wire gauge to use and the proper selection of fuses for various circuits. There will even be information on the soldering and crimping of wire terminals, along with how to insulate them and make a professional looking terminal.

Headlight circuit diagram using a relay

A discussion about relays will be a good place to start. The relay is an electrically operated switch that basically has two parts. The first is the electro magnet or coil. The coil when energized from a power source will create a magnetic field. This magnetic field then activates the second part which is a set of switch contacts. Normally when the coil is energized, it will draw a small amount of current. On the other hand, the switch contacts that are controlled by the coil or electro magnet will have a high current rating. For example, many 12v automotive relays will draw somewhere around 0.25amps when energized. Often many of these 12v relays will have contacts rated at 30amps. Relays are often used in the headlight circuits, radiator cooling fan circuit, horns, fog lamps, starters, and many other high current drawing devices. Often when there is an electrical fire in a vehicle, it is due to using switches that have a very low current rating on a circuit having a large current draw, using the incorrect wire gauge, or even with poorly protecting wiring from shorting out when passing harnesses through frames and various body parts. None of this should scare you off. Maybe you already built the high horsepower engine, or produced that high gloss paint finish on you custom car, not to mention all of the welding you did on the frame. All of these didn’t intimidate you, so why not wire your own hot rod?
Below is a video on a basic 12v / 30amp relay and how I tested it, used it to turn a few lights on and off, and a basic circuit diagram of a headlight circuit.


Building the Patriot Lakester Weld-up Header Kit with Side Pipes

Monday, March 17th, 2014

Building the Patriot Lakester Weld-up Header Kit with Side Pipes
Who said building a hot was easy or quick? Sometimes a minor oversight early in the build can create an issue towards the end of the hot rod build. This is exactly what happened to me with the exhaust system. The first set of headers I built and installed on the 1929 Ford roadster hot rod resulted in a very minor issue. Using the C4 Corvette front suspension and Corvette rims that have a large inward wheel offset, the front tires on a sharp turn would just touch the front primary exhaust tubes. The easy fix would have been to either use different rims, or install a 1 inch wheel spacer between the rim and the rotor. Each of these options did not appeal to me as I wanted to maintain the same dynamics of the C4 Corvette suspension as designed by the GM engineers. Of course, if I had not chosen to maintain the stock wheel base of the 1928-31 Model A Ford wheelbase of 103.5 inches and make the chassis say 6 inches longer, the exhaust problem I have today would not exist. I could have easily recessed the firewall moving the engine back a few inches and again the wheel rubbing on the header would be of no concern. Recessing the firewall was would have been okay for a shorter person, but I am well over six feet tall and loosing leg room would make driving the roadster uncomfortable. I do know the next chassis I build for the Model A Ford using C4 Corvette suspension will be at least 6 inches longer with a wheel base of 109.5 inches. That would allow me to move the coil over shocks inboard behind the radiator, but that will be another story much later on. For now let’s focus on the build of Lakester headers using the Patriot weld-up kit H8001 for the small block Chevrolet engine.
1929 Ford hot rod - Patriot Lakester header kit - picture 1.1
1929 Ford hot rod - Patriot Lakester header kit - picture 2
The H8001 Patriot header kit has 1 5/8 inch primary exhaust tubes with a taper secondary pipe having an outlet size of 3.5 inches. This kit can be real easy to weld up if you choose to bring the primary tubes straight into the secondary pipe and only drilling a 1 5/8 inch hole into the secondary pipe. I never do anything easy and like the style of the primary tubes curving into the secondary tube. With that said, fitting the pipes together tightly before welding will be more time consuming and play havoc will your patience. Then of course wanting to maintain the use of external side pipes will present a challenge of fitting the output of the Lakester headers to the side pipe running parallel to the outside of the frame and just underneath body of the roadster.
The build of the hot rod to me is nothing more than a giant puzzle. I have overcome more complex challenges when I designed the chassis. So the challenges of the Lakester headers and side pipes are only minor. Before I start cutting and welding anything, I always stand back and give the task on hand a considerable amount of thought, sleep on it, dream about it, and think about it some more. Using several wooden blocks, I mocked up the approximate location of the Lakester secondary tapered pipe. I then blocked the side pipes to the location I wanted them. Now it was a matter of mating the output of the headers to the input of the side pipes. Using few bits and pieces of ABS 1.5 inch pipe and fittings, I developed a bit of a plan using 45 degree elbows that seemed to work. Off to the supplier of exhaust parts, I purchased two 90 degree 3.5 inch elbows. Back at home in the shop, these elbows were then cut in half creating 45 degree fittings. To make the mockup of the exhaust system, I quick cut some extra 3.5 inch straight pipe into 1 inch sections. I then cut a small section out of the circumference so that these rings would become sleeves that would fit inside the 3.5 inch 45 degree elbows. Now the plan was starting to come together and in no time I was able to mockup the exhaust system with the look I was aiming for. Now I felt comfortable enough to start welding and making the connections permanent.
1929 Ford hot rod - Patriot Lakester header kit - picture 3
1929 Ford hot rod - Patriot Lakester header kit - picture 4
1929 Ford hot rod - Patriot Lakester header kit - picture 5
Below is a short high definition video of the assembly process I undertook for the second set of headers. In the end, I believe everything happens for a reason, as I do like the look of this exhaust system much better than the first set. So in the end this was time well spent.