Labrauer Posted June 21, 2015 Report Share Posted June 21, 2015 I am wanting to install a fuse block in my P15 coupe to have fuses on all the switches and all the components on the car. I am thinking of changing from 6 volts to a 12 volt system but before I do that rewiring is a must I think. The car was rewired a few years ago with the correct wire size for 6 volt system so I don't know if I can still use the bigger wire used for a 6 volt system or not. I a wondering if anyone has done this and what type of fuse block you used and how many fuses did you use for a completed system. If you have pics I can look at it will be appreciated also. Quote Link to comment Share on other sites More sharing options...
greg g Posted June 21, 2015 Report Share Posted June 21, 2015 6V wires will easily carry 12 V needs. You can buy fuse boxes from all parts stores, just decide how many circuits you want and get the number of fuse slots appropriate to your plan, some even have provisions for relays in the same box. I would do one for ignition off circuits, brake lights, head lights, interior lights, etc, and another for ignition on circuits like heater, starter solenoid, horn, signals, whatever you want to work only with the engine running. you can also power one from the acc terminal if you want to run some items without the ign. on. Quote Link to comment Share on other sites More sharing options...
mopar_earl Posted June 22, 2015 Report Share Posted June 22, 2015 Headlights should be on a self resetting circular breaker and not a fuse. Normally part of the headlight switch back in the day. Not sure if the old cars had them. A fuse blows no lights. A circuit breaker will make the lights come on and off so you at least have something to get off the road with. Might want to disconnect/bypass the amp gauge as they tend to burn cars up. Yes 6v wiring will handle 12v. 12v wiring will not handle 6v. Lower the voltage the bigger gauge wiring is needed. Earl Quote Link to comment Share on other sites More sharing options...
jeffsunzeri Posted June 22, 2015 Report Share Posted June 22, 2015 Don't convert from 6 to 12 volts. In this day of modern, plentiful and effective voltage and polarity converters for any additional components, there is simply no need to molest your vehicle in such a manner. I've added extra circuits for a couple of older vehicles and used a fuse blocks easily available on eBay for very low cost. These use the modern blade fuses, but there are many blocks available which use the glass fuses. I mounted the new block on the interior firewall. I found the block to be easier to access and maintain than inline fuses. The circuits I protected are for the added spotlight, heater blower, turn signals and after-market dash fan. The original wiring scheme protects everything else just fine. Quote Link to comment Share on other sites More sharing options...
Labrauer Posted June 25, 2015 Author Report Share Posted June 25, 2015 One of the reasons I was looking at going 12 volts instead of 6 volts is to give the starter more turning power and maybe in the future adding air conditioning but haven't discussed or come across any information if a 218 engine will carry the load of air conditioning yet. I don't real;ly see why it wouldn't carry the load as other 6 cylinder cars are capable of doing it. Even with the right battery cables and grounds the engine turns over ever so slowly. I have heard and read that going 12 volts make you engine turn over faster and starts faster which I don't know to be true but I believe the people on this forum that say it does. Just a thought and feed backs are more than welcome on the subject Quote Link to comment Share on other sites More sharing options...
Sharps40 Posted June 25, 2015 Report Share Posted June 25, 2015 (edited) Convert to 12 Neg ground using a delco 10SI or 12SI and add a GM HEI (Tom Langdon, Stovebolt Engine Company, Michigan). Combine that with taking the load off your headlight switch and out from under the dash by installing a self resetting circuit breaker and a relay for each of High and Low beam (pulling power directly from the battery) and it'll be the best under $300 ya ever spent on reliability. (Pullys for wide and narrow belts are widely available on the aftermarket to adapt the alternator.) Install the internally regulated alternator first as it won't make the HEI frying voltage spikes of an externally regulated alternator or standard 12v generator. Perfect, smooth and reliable power. Once the HEI goes in, the engine will run stronger, longer and better with higher mpg. Once the relays are in, you can install Halogen or HID headlights receiving the full 14.5 volts at the lights and drive at night with modern car visibility. As for the fuze block, great idea, along with eliminating the often dangerous amp meter in the dash, replace it with a volts gage if you want to see a needle moving around in the slot. These two modifications will reduce your fire hazard significantly. Edited June 25, 2015 by Sharps40 Quote Link to comment Share on other sites More sharing options...
jeffsunzeri Posted June 29, 2015 Report Share Posted June 29, 2015 One of the reasons I was looking at going 12 volts instead of 6 volts is to give the starter more turning power and maybe in the future adding air conditioning but haven't discussed or come across any information if a 218 engine will carry the load of air conditioning yet. I don't real;ly see why it wouldn't carry the load as other 6 cylinder cars are capable of doing it. Even with the right battery cables and grounds the engine turns over ever so slowly. I have heard and read that going 12 volts make you engine turn over faster and starts faster which I don't know to be true but I believe the people on this forum that say it does. Just a thought and feed backs are more than welcome on the subject A good reason to NOT convert to 12 volts is if the engine is not turning over fast enough on 6 volts. Slow turning is NOT a characteristic of a well maintained 6 volt system. As for air conditioning, you can have that too with a 6 volt system. You would be looking at much more than voltage issues if you wanted AC though. Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted June 29, 2015 Report Share Posted June 29, 2015 do pay close attention to the power requirements of the very device to power a 12 volt component from a 6 volt source...you may be shocked at the ratio..and the device itself is usually such that it can power but one said device so a number of devices will be required....that will add up in amperage draw rather quickly.. Quote Link to comment Share on other sites More sharing options...
Labrauer Posted July 1, 2015 Author Report Share Posted July 1, 2015 Thanks for all the great answers guys but I still need to get one more answer from you all. Will a 218 motor carry the requirements and have the horse power to run an air conditioning unit if switched to a 12 volt system? Thanks in advance, Larry Quote Link to comment Share on other sites More sharing options...
greg g Posted July 1, 2015 Report Share Posted July 1, 2015 How does switching operating voltage of ancillaries effect the power output of the engine? Quote Link to comment Share on other sites More sharing options...
jeffsunzeri Posted July 1, 2015 Report Share Posted July 1, 2015 Thanks for all the great answers guys but I still need to get one more answer from you all. Will a 218 motor carry the requirements and have the horse power to run an air conditioning unit if switched to a 12 volt system? Thanks in advance, Larry Short answer is "no". You could switch the electrical system to 3 volt, or 18 volt, or 32 volt, or 24 volt and it would not make any difference vis-à-vis air conditioning. There are only 2 components on an AC system that require system voltage: the blower motor and optionally the compressor clutch. Blower motors are commonly available in a variety of voltages, so are not an issue. The electric clutch on many AC compressors doesn't really care about voltage and can operate with 6 volts, and the amperage required is small, so a converter works well in this case. Many AC systems don't even need or use an electric compressor clutch, so the whole voltage thing is a non-issue. In as-new condition, the 218 makes about 100 HP. The air conditioning compressor is going to use about 3 HP during normal operation, and up to 7 HP or so when initially kicking in. Additionally, the cooling system on the 218 is not designed to accommodate air conditioning operation and the fitment of the condenser. Now add in the condition of the motor, type of transmission, condition of the cooling system, plumbing requirements and you'll likely agree with the factory that the flathead 6 will not support AC. There is a reason the factory didn't offer AC as an option to the flat-6 powered vehicles, as it was on option on v-8 cars from the early '50s. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted July 1, 2015 Report Share Posted July 1, 2015 How does switching operating voltage of ancillaries effect the power output of the engine? In most cases it should be insignificant. There may be some conversion efficiency differences, but the total number of watts (assuming the same set of lighting and accessories) is the same. And even if you add a lot of accessories and lights you probably won't notice a difference because 1hp is about 800 watts of electrical power. Quote Link to comment Share on other sites More sharing options...
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