With the generator out of the way, you can see the stock lower bracket, and how it fits behind the upper portion of the driver's side motor mount.
To remove the stock bracket, I loosened all three bolts, then placed a jack with a piece of wood under the car to support the engine from below prior to working the bracket out of there. (This way, there is very little stress on the motor mount with the upper bolt removed and the bracket out of place.)
The alternator bracket arrived in a matter of days, and was a simple, yet impressive piece of work! The kit contains a new upper and lower bracket, all new hardware, a spacer and instructions. If it installs as good as it looks, it's a Home Run for sure! Also pictured here is a newly remanufactured 63 amp alternator from Advance Auto. It's a common alternator used on GM cars from the mid-70s on up into the 80s, but take a moment to consider how it will be mounted before giving the parts clerk an application to look up. I wanted a single groove pulley and the pigtail hole "clocked" in the 12 o'clock or 3 o'clock position, so I asked for an alternator from a 1979 Pontiac Firebird with a 301 engine. This gets you what you need with no mistakes...Firebirds came with several engine options in the 70s, but the only 301 cube motor was the Pontiac mill, and the alternator location dictates a 12 or 3 o'clock pigtail location...perfect! (If you're mounting the alternator on the passenger's side in typical 70s SBC fashion, ask for an alternator for a 77 Malibu Classic with a 305 engine, and it'll be clocked in the 9 o'clock postion usually, for use on a Chevy motor.)
Nice brackets with pretty welds deserve pretty paint, right?? I gave both brackets a shot of "Deja Blue" metalflake lacquer paint from Testors because I had it handy...and it looks pretty cool, too! Almost gives them an annodized look in the sunlight! As a bonus, it dries quickly...I cleaned the brackets with brake parts cleaner to remove any oils or grease on them, then painted them with a couple coats of the sparkley blue hue, then let them dry while I was removing the stock generator brackets.
The new lower bracket is a snug fit behind the motor mount, just as the stock bracket was, but with the motor supported from below, I was able to slip it carefully into place without messing up my nifty paintwork! The holes aren't drilled any bigger than they have to be, so it takes a little bit of finesse to line them up right. To simplify the job, I got the front bolt started good, then pivoted the bracket into place, wrapping it with a cloth and giving it a few gentle taps until all three bolts went in and could be snugged down. The fit was perfect!
The long 'through bolt' will just clear the radiator and slip into place, and the provided spacer was sized exactly right. I added a washer to each end (outside the bracket) just out of habit, and started the nylon lock-nut on the back. The photo shows how well it all slips together!
A few moments later, I had the upper bracket positioned, and discovered that the original belt from the generator fit the new alternator! I am very pleased with the kit...WELL worth the money and it is a breeze to install! You can see where the 12 o'clock positioning puts the outlet for the pigtail...straight up. If this alternator was clocked for a 70s Chevy small block, the pigtail port would be facing the engine block, making access difficult.
Nice little thread you have going Hack, and the car is great! Are you going to set the headlights up with relays? On the Tri 5's it helps light output quite a bit...especially if you go with Halogen sealed beams.
Now we can start wiring the new alternator. I've included a wiring diagram below illustrating how I like to hook these up. Some people just 'jumper' the 12ga red 'exciter wire' from position 2 on the pigtail over to the 'Battery' post on the back of the alternator, and that will work, but I route it to the "Accessory" terminal on the ignition switch myself. Of course, your ignition switch will also have a battery source wire, so that's where it gets the voltage to distribute to the indicator lamp and the exciter wire. I also like to include an indicator light, and some rebuilt alternators indicate that in order for the alternator to function correctly, you MUST wire in an indicator light or a resistor. I like having the light, so that's what I use. I run power from the "Accessory" or "Ignition" terminal on the key switch through the light bulb then to the number 1 terminal on the alternator pigtail (usually a 14ga white wire). This way, when you turn the key "on", your indicator lights, and it will go out once you start the engine and rev it once to 'kick in' the alternator and start it charging. If the light stays on, or comes on when your driving, you know the alternator isn't charging. (In the case of this car, I will use the stock "GEN" light in the factory instrument cluster for this purpose. In other cars, I've used small amber dash panel indicator lamp assemblies commonly found at truck stops. Whatever light you use, just run power THROUGH the bulb (do not use a grounded socket) back to the alternator pigtail and it'll work fine. You need a two-wire, non-grounded light socket for this, obviously.
Word of caution here.Seen a couple of batteries blow over the years from sparking.Not nice to you or the car.Might want to check negative where it bolts to engine/frame,away from battery.You could also hook up wires to posts with leads away from battery with roach clips..ooops..my 60's-70's upbringing is showing..make that alligator clips.
Before daylight faded today, I was able to start making my Alternator Harness for this car. I use a 10ga red wire for the 'Batt' terminal on the back of the alternator, and usually a 12ga red wire for the exciter wire, and a 14ga white wire for the indicator lamp wire, both of which are in the pigtail. (You can get new alternator pigtails with short lengths of wire from any good parts store for about three dollars). In factory applications, there is a rubber 'boot' which protect the battery post on the back of the alternator. That is the heavy 10ga wire that carries all the output from the alternator, so you don't want anything accidentally touching it and grounding it out...as it is 'hot' all the time, even when the engine isn't running and the key is off. I always include a factory boot on my cars. I snip the wires off any GM parts car I scrap and save these boots for future use. Slip the boot over the 10ga wire BEFORE you crimp on the ringlet connector and it;ll fit snuggly over the battery wire once you hook it up. Here you can see the start of the Alternator Harness with the boot in place, and a shot of the wires all hooked up to the alternator and the first couple feet of the harness banded and tightly wrapped. This is as far as I got today...more to follow. (Not sure how I want to route the Alternator Harness just yet, I'll let you know in an upcoming installment!) A quick note regarding that heavy 10ga battery wire coming off the back of the alternator...it supplies all the power to run the car and all of it's accessories once the engine is started, as well as carrying the charge current back to your battery. You can hook it up one of several ways, but it needs a path back to the positive battery post to work. In applications where the alternator is on the same side of the engine as the starter or starter relay, I often run that 10ga wire to the battery cable at the starter stud or relay. In this case, the alternator is on the opposite side of the car from the starter and battery, so routing may be a little different, I'll discuss these options later.
Good point, and you are absolutely correct! I mentioned this in another thread where someone was testing headlights by touching wires to the battery. I'll often test small bulbs right on the battery, but heavy draw components make a healthy spark when you touch wires to a battery...and believe me...I learned a LONG time ago what can happen then! (You explode a 12v car battery one time...and you'll be REALLY cautious around them for the rest of your life...trust me on that one!!!)
Thanks! I usually run relays on my headlights, but not always. I haven't decided on this project yet. (The last car I wired did great without them, but I used a switch from a 1970s Ford that easily handles and distributes the power. I tested the headlights with an ammeter and found that they only drew 5amps for both low beams, and only 10amps for both high beams...less than I had thought.)
Wiring is the next thing on my list, thanks for simplyfing it for us, I feel less stressed by it now...
Tri five Chevy's are a bit under wired to the headlights from the factory... So are Buick's and Pontiac's... Pretty much all of the other manufactures and that included Oldsmobile used 16 or 14 gauge wire on the headlamps... Chevy's choice was 18 gauge... A might dinky considering todays lighting requirements. Then add in the years of corrosion at connections, wear at the light and dimmer switches and the amount of resistance in the circuit goes way up. Take a voltage reading at the headlamp and compare it to the battery voltage to see just what the difference is. You might be amazed. Two volts in a 12 volt system is a 17% loss in voltage to the headlamp. I have tested some early Chevy's and seen as little as little as 10.2 volts at the headlamp with the engine running 1000 rpm. System voltage at 13 + volts. Over 20% loss in power at the headlamp. Relays are simple to wire into the front harness. Al
Exactly. I wired a friends 57 with headlight relays and we were both AMAZED at the difference. It was a white knuckle ride at night before the relays.
The relays do work well, I've used them in the past on several cars and they're easy enough to wire, but not always necessary, in my opinion. I didn't keep any of the factory wiring at all (never do). The original headlight wires were really puny, as noted, but my new ones are 14ga, all new wire, new bulbs, new connectors, dedicated ground wires and a new switch on the way. Every connection is coated with No-Ox-Id protectant as well. I have plenty of room to install relays if desired, but haven't decided for sure yet. (I wired CathyH's 51 Mercury from scratch without relays and those lights are plenty bright. With new, properly sized wires, good connections and most importantly...good a good GROUND, I think the need for relays is minimized. That's one reason I run dedicated ground wires from each component (especially headlights) back to a 'ground junction' that effectively has the lights grounded right to the battery. I keep the factory body grounds, but 'supplement' them with my own ground wires. With new 'oversized' wires and excellent grounds, voltage loss is greatly reduced.)
Great thread. Just have one question: I know you said you never use turn signals but why not go ahead and wire them since the car came with them originally and just not use them? You never know when you might change your mind.
That may happen soon, but not right away. It would be a simple 'upgrade' to add them later (though it would've been easier to do it from the start, sure) if I want to go that route, but for the sake of this demonstration, I'll stick to showing what it takes to give a car the very basics when wiring a car from scratch.
Okay, my goal for today was to get the Main Engine Harness done and routed into the car. Just as I did with the Rear Light Harness and the Front Light Harness, I wanted to combine the ignition, starting and charging circuits into a Main Engine Harness and get that planned, banded, wrapped, routed and installed before sundown! I considered a few different routing options for the alternator wiring, but elected to run the wires back along the driver's side of the engine to the firewall area. The factory generator wiring runs from the generator, over to the regulator and horn relay next to the radiator, then back along the driver's side inner fender panel to the interior. I could've routed the alternator wires in a similar fashion, or wrapped them around the front of the engine and down the passenger's side, but in the end, I thought the 'cleanest' method would be to go straight back toward the firewall on the driver's side. I took care, as always, to secure the wires well and protect the wrapped harness with rubber hose in key areas. Also, keep any moving parts (such as throttle linkage) in mind when routing wires...and keep your harnesses out of harm's way! To understand what wires will do what and go where, take a look at the crude diagram below. All wires heading off the top of the page are ones that go into the interior through the original engine wiring grommet. They will be hooked up later, but this drawing shows how I wired the basic engine components. The heavy 10ga red wire coming off the output stud on the alternator runs down the driver's side of the engine then across the firewall and down to the battery cable stud on the starter solenoid. Also hooked to that stud (in addition to the positive battery cable of course) is a super heavy (slightly bigger than 10ga) brown wire that follows the same path back along the firewall and into the interior. This wire will provide power to the fuse panel and key switch, so it carries the juice to operate everything. The other two wires from the alternator (pigtail wiring) indicated in red and pinkish on the drawing are the exciter wire and the indicator lamp wire, and they run along the engine and into the interior where they'll be hooked up to their proper locations later as well. The ballast resistor for the ignition has a green wire going into it from the key switch to provide reduced voltage to the coil during normal operation, and the blue wire going from the resistor to the coil also has another blue wire joining it at the output side of the resistor to provide full voltage during cranking to the coil. (55 Chevy key switches have a provision to do this, otherwise the normally un-used "I" terminal on the starter solenoid can do it). The dark red wire runs from the "S" terminal on the solenoid into the interior where it will be hooked to the key switch. It is used to crank the engine over. That's the Basic Engine Harness in a nutshell! There isn't much to it, but it still gets kinda crazy while your building it, as we'll soon see!
Here's the work in progress! At this point, it looks like Johnny Sokko's robot threw up under the hood or something, but it eventually gets sorted out, banded up, neatly wrapped, then routed and tucked into place...trust me! You can see the two large ringlets that will attach to the starter solenoid stud along with the battery cable, and the rest of the wires involved in the Basic Engine Harness. It's a pretty tedious and daunting task to get this mess in line and routed...but it's something you should only have to do once (if you do it right), so it's worth the time, effort and mild frustration now...as it will provide years of trouble-free service later!
And...a while later...here's what we end up with! The Basic Engine Harness is done, wrapped, routed and installed under the hood, and this is what it looks like. Of course, later one we'll find that mess of wires spilled all over under the dash, along with the Front and Rear Light Harness wire ends...but we'll deal with them next time! At this point, you've got all the main harnesses routed into the under-dash area for final fitting, routing and hook-up, and there's only a few other small additions to make before we get to that point...but I'll cover that next time! While not a "professional" job, this shows you that anybody can do a decent wiring job in their back yard with basic tools and a little time and effort. There's still a long ways to go, but at least it's starting to look like something now!
If you are running 14 gauge wire to your headlights you do not need relays. Even 16 gauge with good connections and switches will handle most headlamp arrangements. The relays are a good way to FIX a poorly wired car and brighten the lights without having to pull wire all the way from the dimmer. I would suggest a 4-6" length of 16 AWG fusible link wire at the ends of the 10 gauge wire from the BAT terminal on the alternator and the end of the fuse panel feed wire at the starter solenoid. They can prevent a major meltdown if something shorts out. Al
Okay, where were we? Oh yeah! The Main Engine Harness and the Front Light Harness were completed, wrapped and installed under the hood and through the factory grommets in the firewall, and the Rear Light Harness was installed and routed so that the wire ends were under the dash, also. At this point, you'll have several wires under your dash (behind it, more accurately) and all ya gotta do is trim 'em, put the correct ends on 'em, hook 'em up where they go and secure them neatly out of harm's way! Working within the confines of most dashboard areas is masochistic, at best, but you can make things a little easier by removing the gauge cluster in this case. (Other vehicles allow other 'tricks', such as 49-54 Chevys with the convenient access panel on the firewall, and Ford?Mercury products of the 50s with their easily removeable dashes!). This is where we're starting from in this segment...
I removed the stock fuse panel and installed a new aftermarket one from Buss in it's place. The Buss panel accepts the newer, common "blade type" fuses that I like to use. On a 55 Chevy, the holes from the original fuse panel almost line up for the Buss fuse panel, so I just elongated one hole slightly and the mounting screws fit perfectly! (The brass screws are what I chose to mount the panel with, seen here from under the hood on the firewall, along with a shot of the new panel in place under the dash where the stock one used to live.)
The new fuse panel has a stud on it where you hook up incoming power. For this, the Primary Fuse Panel (hot all the time), I hooked the heavy brown wire coming off the starter stud to the input stud on the panel. This provides power to all six fuses once the fuses are selected and pushed into place. Now, with the fuse panel getting power (well, not really...you DO leave the battery disconnected while doing this, but you know what I mean!) we can begin to hook things up to the panel...those 'things' being our various switches! Luckily, a fresh box of "goodies" from Bob's Classic Chevy arrived about this time, including things like a new headlamp switch, some new factory grommets (didn't end up needing them, but better safe than sorry!), a new stoplight switch, new outer tail light lenses and a new lock cylinder for the ignition switch. (The joke was on me with that last item, as they are not a replaceable item...you need a whole new ignition switch!)
The Jalopy Journal
