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New Fuse Block system.. engine bay or under dash?


GarageStudios

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Hello,

I have decided that my car will be converted to a 12v system, all new wires as I have the car fully accessible..

 

Seen some great videos on building a fuse block with relays, terminals and boards on  ABS plastic.. weatherproof etc.. 

 

But often wondered.. I have seen both ways done in antique cars.. some have in engine bay, others wire them in under the dash.. some do both as a split..

 

What would you recommend? All I'm running is lights, heater, dash gauges, small indicator lights wipers horns  and maybe in the future the original radio..

 

Thanks

Edited by CDN224 (see edit history)
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Leave it stock. There is no reason to convert. If you must, install led’s and let it go at that. They built millions of cars  that ran on 6 volts. They worked fine when new. 
 

The factory radio won’t work on 6 volts. 
 

PS- since 12 volts uses much less amperage, there is no need to change the wiring. You only need to switch lamp sockets and bulbs. If it’s a positive ground you need to switch the amp guage wires. To be honest, if you don’t know this off the top of your head, you will probably encounter severe difficulties in trying to change it over. The coil also needs to be changed. Make your life easy, keep it stock. 

Edited by edinmass (see edit history)
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What edinmass said.

But If you are determined to do this, especially with new home made wiring harnesses and a system from a You Tube video that includes relays etc, place it where you can easily get to it.

I suggest near a fire extinguisher. ............Bob

Edited by Bhigdog (see edit history)
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1 hour ago, Hubert_25-25 said:

It needs to stay clean and dry.  If under the hood, it has to have a cover where no water can get on the fuses or connections.  Most fuse panels are open.  With an open fuse and relay panel, the best place is under the dashboard.   

 

There are a lot of sealed underhood fuse panels available in wrecking yards these days. There are also brand new ones available. This aftermarket Bussman is just one example.

 

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20190313_173450-jpg.82093

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22 minutes ago, Rusty_OToole said:

Given that the OP thinks converting to 12v will solve his problems, but doesn't know where to put the fuse panel, I predict that he will be accessing it a lot. I also predict that this will not be his last  question

 

Agree. Usually changing from 6-12 volts has more issues than just fixing the 6 volt connections.

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2 hours ago, Rusty_OToole said:

Given that the OP thinks converting to 12v will solve his problems, but doesn't know where to put the fuse panel, I predict that he will be accessing it a lot. I also predict that this will not be his last  question

 

That's an inappropriate characterization of the question. The OP has two potential locations and was asking pros and cons. That's not the same as "doesn't know where to put the fuse panel".

 

And yeah, I get that AACA is all about preserving stock configurations, but the reality is that, barring oddball systems like some of those Chrysler transmissions, converting from 6V to 12V isn't the rocket science that people try to make it out to be. People have been doing these conversions for well over half a century. The voltage reducers needed to retain the 6V gauges and radio and such are readily available. The fact of the matter is that the problem is voltage drop, and short of installing a brand new harness with brand new connectors everywhere, the 12V system is a lot more forgiving as far as resistance and voltage drop at connections.

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33 minutes ago, joe_padavano said:

 

That's an inappropriate characterization of the question. The OP has two potential locations and was asking pros and cons. That's not the same as "doesn't know where to put the fuse panel".

 

And yeah, I get that AACA is all about preserving stock configurations, but the reality is that, barring oddball systems like some of those Chrysler transmissions, converting from 6V to 12V isn't the rocket science that people try to make it out to be. People have been doing these conversions for well over half a century. The voltage reducers needed to retain the 6V gauges and radio and such are readily available. The fact of the matter is that the problem is voltage drop, and short of installing a brand new harness with brand new connectors everywhere, the 12V system is a lot more forgiving as far as resistance and voltage drop at connections.

 

 Thank you, Joe.

 

  Ben

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I have made a LOT of money over the years fixing 6 to 12 volt conversions, enough to pay for a drivable Pierce Arrow. He still has to figure out an alternator, and if electric wipers.....more issues. They built MILLIONS of 6 volt cars, and they drove billions of miles. And they actually worked and were reliable. Fact is most shady tree mechanics today have less than 1/3 the ability of what was common years ago. Look how many JB Weld questions are posted here. Simple fact, old cars are work, and they cost money........more of both than they should be. I put 80 hours in a suspension system over the last month..........on a big pre war car. I’m almost done. I don’t do it with short cuts, or make temporary or half assed repairs. I fix it just like the factory built it........and presto.........everything works great. Where do you stop? Electronic ignition? 12 Volt systems? Radial tires? Good cars sell.......fast, and for more money the the rolling junk yards. If you hired me to look at a car for you, and you told me it was converted to 12 from 6, I would refuse the job. I don’t need to see the work.......it was and is a hack job......,,in every case. Just my two cents. I do NOT want to insult or  scare off any members here, just trying to share a lifetime of experience.

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12 minutes ago, edinmass said:

I have made a LOT of money over the years fixing 6 to 12 volt conversions, enough to pay for a drivable Pierce Arrow. He still has to figure out an alternator, and if electric wipers.....more issues. They built MILLIONS of 6 volt cars, and they drove billions of miles. And they actually worked and were reliable.

 

I agree, my 1922 Cadillac (positive ground as well) is bone stock, asides from a rewire to replace the degraded original wiring and it will start almost instantly from cold - when properly adjusted it should be nearly identical to a modern car (on a cold day, the cad probably fired quicker than my old bmw) 

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joe you have been around these forums long enough to know there are always newbies who think if they change to 12V, or for that matter, throw a Chevy V8 in their car their troubles will be over. Followed by a series of panicky questions followed by silence, almost never by pictures of the complete running car showing a smiling satisfied owner.

The old timers are the ones who carefully diagnose the problem and then fix or replace just the bad parts, with as close as they can get to the OEM parts.

I'm not trying to insult the OP just pointing out a few facts of life.

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39 minutes ago, edinmass said:

I have made a LOT of money over the years fixing 6 to 12 volt conversions,

 

Since I doubt people have you fix conversions that are working fine, that's not exactly a statistically valid sample.

 

Do people who think they are capable of modifying a car screw up and make it worse at times? Sure they do (cue the disc brake discussion), but these same people are likely incapable of maintaining a car in stock condition as well, so that has nothing to do with the conversion and everything to do with a lack of skill. As for millions of cars with 6V systems driven billions of miles, the reality is that these cars were never designed for a 50 year, 75 year, or longer lifetime. Electrical connectors are not weather sealed and the terminals DO get dirty and corroded, which causes significant voltage drops. Heck, GM cars in the 80s had this problem until GM finally completed their conversion to Weather Pack and MetriPack sealed connectors. Can you painstakingly clean every single electrical terminal in the wire harness to return the 6V system to it's new-car functionality? Of course you can. Is a 12V system a more expedient way to overcome this problem? Perhaps. I'm not suggesting it's the answer to every situation, just that it IS possible to make it work without a EE degree.

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9 minutes ago, Rusty_OToole said:

joe you have been around these forums long enough to know there are always newbies who think if they change to 12V, or for that matter, throw a Chevy V8 in their car their troubles will be over. Followed by a series of panicky questions followed by silence, almost never by pictures of the complete running car showing a smiling satisfied owner.

The old timers are the ones who carefully diagnose the problem and then fix or replace just the bad parts, with as close as they can get to the OEM parts.

I'm not trying to insult the OP just pointing out a few facts of life.

 

True statement, and as I alluded to above, the "four wheel disc brake conversion" is a great example of a potentially destructive upgrade if the person doing the work isn't well versed in brake system design and implementation.  And you are correct to point out that there are pitfalls that the uninitiated may not be aware of.

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15 minutes ago, joe_padavano said:

 

Since I doubt people have you fix conversions that are working fine, that's not exactly a statistically valid sample.

 


NONE of them work fine. Ask people with experience.......someone with 4 or 5 thousand hours in the shop. Run it by Matt Harwood.......bet he wouldn’t take a car on consignment that has been converted. There is simply no good reason to do it. The 6 to 12 volt guys do it because they can’t fix their way out of a paper bag, or they think it will be cheaper........and multiply that by everything they touch on the car, and you have a mess on wheels.

Edited by edinmass (see edit history)
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I'll tackle the original question then...

 

If you put it it under the hood, it is more subject to corrosion, but easier to get to it to work on. On the downside, you will have to run an individual wire through the firewall for each circuit inside the car. The less holes in the firewall the better, not only for it's original purpose, but to keep fumes out of the passenger area.

 

If you put it under the dash, and you have to get under there to do anything, and that can be very inconvenient. Also, some of the bigger fuses might be better off under the hood (like for the charging system etc.). It is no accident that many modern cars have one fusebox under the hood and one outside.

 

Some hints for wiring cars:. Voltage drop is a big deal. Every single connection adds more voltage drop. Every crimp, every fork or ring terminal over a screw, every spade, every spot a terminal is CRIPMED on a wire (and not soldered), etc. every time one piece of metal is bolted or riveted to another, every light socket. ALL of these things add voltage drop, and all of them get worse over time. When you wire a car from scratch, do everything in your power to minimize the number of connections.

 

When in doubt, use bigger wire.

 

A fuse is there to protect the WIRE, not whatever is attached to it. So, wherever a new circuit begins, and the wire size gets smaller, thats where the fuse needs to go.

 

Lets take a set of fog lights for an example of what I mean by that. In this example we are going to run a hot wire to the battery. (that maybe isn't the best place in real life, but bear with me.) The fuse should go at the battery. If a short should occur somewhere down the line, the fuse will blow and the wire will be fine. If we put that fuse at the switch, or the relay, or the lights themselves, and a short occurs at some point in-between the battery and the fuse, the wire from the short back to the battery will catch on fire with the full force of the battery and charging system.

 

That last consideration is really the most important.

 

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Bloo.......your correct in your analysis........exactly why a non professional should not attempt the job! Without all the necessary supplies, tools, and a practical understanding of an electrical system, you end up with a rats nest of a mess. 

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For electrical connections, solder fixes a host of ills. 

 

If the clamp force on the female connector is clean and tight, just soldering the terminal to the wire will be more than sufficient.  Make terminal needs to be clean also.

 

Clean terminals, both sides along with a good crimp connection is the key to dependable electrical systems.

Edited by Larry Schramm (see edit history)
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Having worked on vehicle electrical systems off and on for a little over 40 years, some professionally and some as a hobbyist, I have still never seen a conversion that wasn't a half-assed mess.

 

I have worked on a LOT of cars that weren't in the shop primarily for electrical issues. Electrical systems weren't even my main thing, driveability was. (There is quite a bit of overlap).

 

No doubt some exist, but I simply don't believe there are many. If they were all over I think I would have seen one by now.

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3 minutes ago, Bloo said:

Having worked on vehicle electrical systems off and on for a little over 40 years, some professionally and some as a hobbyist, I have still never seen a conversion that wasn't a half-assed mess.

 

I have worked on a LOT of cars that weren't in the shop primarily for electrical issues. Electrical systems weren't even my main thing, driveability was. (There is quite a bit of overlap).

 

No doubt some exist, but I simply don't believe there are many. If they were all over I think I would have seen one by now.

 

When I was out as a GM Service Rep and a car came in with strange electrical issues, the first question that I asked was, "Does the car have any aftermarket ANYTHING?  Things like alarm systems, cut out switches, aftermarket radios, amplifiers, etc..........  If it did, then the first thing was to remove it and repair all of the damaged wiring.  Surprisingly after everything was removed and damaged fixed the car did not have any gremlins in the electrical system.

 

I learned that lesson early.  I bought a car that had an aftermarket alarm system installed.  The car did all kinds of weird things and the gauges moved randomly.  After I removed the alarm system and fixed all of the wires that had scotch locks on them, the car worked perfectly.  No more electrical problems.

Edited by Larry Schramm (see edit history)
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One of my favorite things when I had my modern shop back in the 80’s and 90’s was the intermittent no start, no crank, or some other random stalling and no start issue. First thing I would do before any service or repair is tell the customer it was going to be 100-400 dollars to remove the alarm system some 16 year old kid installed at the Sears Roebuck garage. They always would insist it wasn’t the alarm, even though it started the day after the install. They would hack the factory harness so bad that often we would have to take photos of what we found and repaired. You really couldn’t fix it correctly without a new harness. By 2000 we were seeing people putting in asinine speaker systems that would draw 70 amps.......and all the hacked installed cables running through unprotected holes cut into the unibody. It never ends.......

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PS- if anyone needs one, I have wiring diagrams for almost every single car built since 1908. Even the crazy weird stuff..........1910 Knox, 1912 Apperson......ect..........only American applications. My stuff goes up till the war. Just PM me and I will be happy to scan it and send it to you.

Edited by edinmass (see edit history)
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8 minutes ago, Larry Schramm said:

 

Sounds like we both have "been there, done that" 


 

Yes!

 

Don't forget the Electric fuel pumps installed on the ignition circuit on 90 percent of the cars what have been “upgraded” today. A twenty amp pump on a six amp circuit........under volting the primary and overloading the switch........gee, wonder why it dies going down the road after one or two miles, then it sits for an hour and starts right up and does it again. Seems turning your wiring harness into a toaster (heating element) causes voltage and amperage drop. 

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Opened a can of worms, CDN.

 

  I would use Joe,s idea and do a weather proof one under the hood.  I did not and wish I had.  With all respect to Matt , Ed and Larry ,and others, we are not all the same. THANK GOD.  Your car is pretty simple, wiring wise.  IF the wiring is in good shape, which I bet it is not, the six volt wire will handle the twelve volt ok.  If a lot more amps are needed, an alternator will be best. A twelve generator will work if extra amps are not needed. I used a GM one wire rebuilt alternator from the local parts store.  8 years and 20,000 miles later and it all still works.  I bypassed the amp meter and use a volt meter.

 

  I will give any help you need.  We "poor , lazy, shade tree mechanics" have to stick together,😛

 

  Ben

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Ben, in his first post he said he was restoring the car. That’s why I implied he would be much better off staying stock. If he was building a rod, 12 volts makes sense. 

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