One of the biggest weaknesses in older cars is the electrical system. These were typically marginal from the factory and don’t age well. Marginal size of wire, corrosion in connectors, switches, and wire, and 50 year old insulation all combine into a lurking dragon waiting to pounce at the worst possible time.
It is easy to find horror stories about melted connectors, burnt wiring, dash fires, and engine fires in old cars. Plus the reliability problems of things simply not working or not working well.
In addition to the steady weakening of the electrical system as it ages, demand for power increases. Traditional headlights have been replaced with high power quartz headlights. Radios have been replaced with infotainment systems – a modern infotainment system with a big amp can require more power than the entire car did in 1963! In addition there are more electrical devices in use today than 50 years ago.
I’ve really gotten used to the headlights in modern cars. I’m reaching the point of “enhanced maturity” where I don’t see as well at night as I used to, and powerful headlights are more a necessity than a luxury. The original headlights in the Imperial look like they are using actual candles!
The Imperial came with a 35 amp alternator; air conditioned cars like mine were upgraded at the factory to a “high capacity” 40 amp alternator. In comparison, modern cars have 100+ amp alternators with many exceeding 200 amps.
Fortunately something can be done about this!
I’m using two main references: first is a set of tutorials on the Bodenzord website going into great detail on how to build a modern wiring system. These tutorials are superb and have cost me a lot of money in parts and tools.
The second is Daniel Stern Lighting which provides a lot of insight into upgrading lighting systems. This site is complementary to the Bodenzord site and makes clear the importance of wire size, relays, grounding, and headlight and bulb selection.
These two sites educated and inspired me to plan significant upgrades to the Imperial wiring, including:
- Think about and design a set of modifications and improvements to the electrical system.
- Upgrade the factory under-dash fuseblock to a modern fuseblock. The original fuseblock contained six glass fuses. The new fuseblock has 20 ATC Mini fuses on two separate buses – 10 switched/accessory and 10 unswitched/always on. Each bus is driven with 40 amps of power through new wiring.
- Bypass the ammeter. This is perhaps the greatest weakness of old Mopars – the entire electrical load is routed through a gauge in the instrument cluster. I’m bypassing the ammeter and routing most loads through new wiring. The only downside is that the ammeter no longer shows charging status. I will be adding a voltage meter as part of the upgrades – voltage meters are actually more useful in determining what is going on with the electrics.
- Changing how power is delivered from the alternator and battery to the rest of the electrical system.
- Upgrading the firewall bulkhead connector to a modern waterproof design.
- Adding a new under-hood fuse and relay block.
- Moving heavy loads like headlights from the factory wiring to new wiring.
- Moving all heavy loads from switches to switch/relay configurations.
- Installing new upgraded wiring for major circuits – typically one to two sizes heavier wire for each circuit.
- Redesigning the alternator circuit with larger 60 amp alternator, heavier wiring (go from 12ga to 6ga), and a solid state voltage regulator.
- Upgrading the grounding system. Many electrical problems, especially in older cars, are due to poor grounds. The grounds are just as important as power!
- Labeling everything to simplify troubleshooting and to help me when I have to work on something in a couple of years.
Next: Electrical 2: Grounded
Things you can sort of do: Take an alternator from a 1940’s car, have a student hold the leads, and do a short turn of the alternator to show the dangers of electricity. [That was standard in our 1990’s physics classes.]
Things you probably should not do: Take an alternator from a modern car, have a student hold the leads, and do a short turn of the alternator.
[When the old DeSoto one burned out in the lab, someone thought “Hey lets take one from that car I am junking”. Thankfully the head of the lab had the grad students run it through a voltmeter/ampere-meter before using a student. The difference in current was impressive enough that a memo was sent out that this was NOT to be contemplated <>.]
Hmm, 1940’s would have been a generator not an alternator, wouldn’t it? Generators don’t produce much power at low RPM.
1990’s would definitely be an alternator which would have a lot more kick in this situation!
You are right.. It would have been a dynamo. [And my knowledge of car parts needs a refresher].