Author Topic: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)  (Read 2232 times)

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Caddy Gurus,
I am switching my stock '47 Series 62 from 6v to 12v in order to add air conditioning (FLORIDA IS HOT!)... *plus* my points-style distributor went out yesterday, so I am also planning to switch over to a Pertronix electronic ignition system. I want to do this right and write a "how to" post when I am done so that all of the info will be out there for posterity. However, in order to get started, I am trying to build my parts list. I have compiled what I have below from various sources on the internet, which may or may not be right. Can you please review what I have below and check it for accuracy?

PARTS LIST:
1) 12v CS121 Alternator with bracket from Steve Passmore + pulley
2) new belt for alternator
3) 12v battery << any advice on what battery to get?
4) Petronix Ignitor Ignition System #1183
5) Petronix Flamethrower coil #40011
6) New spark plug wires << any recommendations?
7) New spark plugs (regap them)
8) 12v to 6v reducers -- one for the heater blower motor, one for the gauges
9) 12v horn relay
10) 12v headlight relay
11) Misc 12v light bulbs (headlights, tail lights, etc)
12) 12v starter solenoid << do I need this (there seems to be some debate here)???

Thanks in advance for your help!
-Justin
1947 Cadillac Series 62 Sedan

Offline bcroe

  • Posts: 3895
PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #1 on: February 16, 2018, 02:37:41 PM »
What about your radio?  Bruce Roe

Offline Art Gardner CLC 23021

  • Posts: 1605
  • Name: Art Gardner
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #2 on: February 16, 2018, 03:13:06 PM »
Leave the 6v starter alone -- no need to change it to 12v.
Art Gardner


1955 S60 Fleetwood sedan (now under resto)
1955 S62 Coupe (future show car? 2/3 done)
1949 S60 Fleetwood sedan (restored 30+ yrs ago)
1958 Eldo Seville (2/3 done)

Offline jackworstell

  • Posts: 341
  • Name: J L Worstell CLC #7558
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #3 on: February 16, 2018, 10:40:25 PM »
BCROE........what do you think of this to supply 6V  ( from 12V ) to the radio  ?

https://www.ebay.com/itm/GEREE-Mini-Buck-Voltage-Converter-DC-to-DC-Step-down-Transforme-Free-Shipping/272665596273?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Jack Worstell     jlwmaster@aol.com

Offline bcroe

  • Posts: 3895
PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #4 on: February 17, 2018, 12:20:31 AM »
That converter might be big enough, check your warmup current. 
However it is a big radio interference generator, which you can
contain in a shielded box with noise filters on input and output. 
It won't be happy with the spikes generated by the starter motor,
put a big 24V Trans Zorb on the input for protection.  And since it
works on positive input, positive output, check that your radio will
work on either polarity.  If it has a 6 pin vibrator, it will need to be
converted to work on pos (negative ground).  Plugging in an
electronic vibrator should do it, since these use diodes to select
the desired polarity.  good luck, Bruce Roe
« Last Edit: February 17, 2018, 09:21:37 AM by bcroe »

Offline Steve Passmore

  • Posts: 5768
  • Name: Steve Passmore - Sadly Deceased
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #5 on: February 17, 2018, 06:27:29 AM »
Caddy Gurus,
I am switching my stock '47 Series 62 from 6v to 12v in order to add air conditioning (FLORIDA IS HOT!)... *plus* my points-style distributor went out yesterday, so I am also planning to switch over to a Pertronix electronic ignition system. I want to do this right and write a "how to" post when I am done so that all of the info will be out there for posterity. However, in order to get started, I am trying to build my parts list. I have compiled what I have below from various sources on the internet, which may or may not be right. Can you please review what I have below and check it for accuracy?

PARTS LIST:
1) 12v CS121 Alternator with bracket from Steve Passmore + pulley
2) new belt for alternator
3) 12v battery << any advice on what battery to get?
4) Petronix Ignitor Ignition System #1183
5) Petronix Flamethrower coil #40011
6) New spark plug wires << any recommendations?
7) New spark plugs (regap them)
8) 12v to 6v reducers -- one for the heater blower motor, one for the gauges
9) 12v horn relay
10) 12v headlight relay
11) Misc 12v light bulbs (headlights, tail lights, etc)
12) 12v starter solenoid << do I need this (there seems to be some debate here)???

Thanks in advance for your help!
-Justin

Leave your horn and starter relay alone. I have never changed either one of these after decades of use. Your horn only works momentarily so won't be a problem and as long as the car is a good starter it's relay will be fine. Have a pump of some sort to bring fuel up after standing so you don't overheat the starter.
You don't necessarily need new spark plug wires either
As Bruce said you will need to know the draw on the heater motor. I couldn't find what mine was so I bought a bunch of resistors to experiment. They are not expensive if you buy direct like these.  I settled on this one which works really well but there's a myriad of OHMS and WATTS available.

https://www.digikey.co.uk/product-detail/en/te-connectivity-passive-product/HSC1001R0J/A102106-ND/2055297
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

Offline bcroe

  • Posts: 3895
PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #6 on: February 17, 2018, 09:28:44 AM »
The problem using resistors on a big draw heater motor, is they
will generate a lot of heat, and the variable speed control will
not function as well, possibly even burning out.  It might be
cheaper, certainly more power efficient and effective to use
another DC-DC converter as suggested for the radio. 

I believe that is not a more modern permanent magnet motor,
so the polarity change will be no problem.  Bruce Roe

Offline Steve Passmore

  • Posts: 5768
  • Name: Steve Passmore - Sadly Deceased
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #7 on: February 17, 2018, 09:41:50 AM »
I found the 50 watts did generate some heat as you say Bruce but mounted in the engine bay of my coupe where it got fan air it has functioned well. I fitted the 100 watts in my convertible which barely gets warm and on both cars the variable speed functions really well. Both have been running well for 2 years. I was guided by a good friend of mine in the US who is head of an Electrical company.  Just my experience.
Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #8 on: February 17, 2018, 10:39:01 AM »
A few reactions:

1) I did forget about the radio -- mostly because there are NO GOOD AM RADIO STATIONS in my area! ;) That said, I think for my 'how to' page I am going to recommend a place that will switch out the internals of the radio to modern electronics, incorporating bluetooth technology. the purists will have to forgive me!

2) I will leave the starter alone (thanks Art & Steve). the same goes for the horn (thanks again Steve)

3) Steve, can you tell me more about what I need to do with a fuel pump in order not to overheat the starter on a cold start? Are you talking about swapping out the mechanical, in-engine bay pump for an electrical, in-tank pump? If so, do you have one that you recommend?

4) Does anyone have a battery recommendation? ...or even just specs that I should be considering?

5) In terms of the heater resistor, this is the one I am looking at including: http://www.vintageautogarage.com/Heater-Blower-Motor-Reducer-12-volt-to-6-volts-p/hr01.htm. Please let me know if you guys see any issues

6) In terms of the headlight relay, this is the one I am looking at including: http://www.vintageautogarage.com/Headlight-Relay-12-Volt-Kit-p/rlk-1.htm. Please let me know if you guys see any issues

7) my car has fog lights. should I use the same relay for the fog lights as what I use for the headlights?

Thanks again!
-Justin
1947 Cadillac Series 62 Sedan

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #9 on: February 17, 2018, 10:41:27 AM »
One more thing...
I've done a fair amount of automotive wiring in the past, but have never worked on a car this old. Can I simply splice & solder like I would on a modern car? Are there any particular gotchas I should be aware of?
1947 Cadillac Series 62 Sedan

Offline Steve Passmore

  • Posts: 5768
  • Name: Steve Passmore - Sadly Deceased
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #10 on: February 17, 2018, 11:51:53 AM »
I found even the 50 watts gets hot so I don't think that 40 will be any good, besides he doesn't state what ohms it is. This is where it came into trail and error with mine. Too many ohms and now power gets to the motor. Too few and the resistor makes no difference. Bruce can probably tell you how to check what your motor pulls in watts? The later motors are probably more powerful than mine.

The light relays will work but I have never fitted them to any of my conversions. Not really necessary as fewer amps in 12 volt.

Wiring connections are no different.

I was referring to fitting an electric fuel pump near the tank, not removing your original.  Seems too simple but I have fitted these on several cars with great success. Fit them down in the hood and you just prime up the carb manually. Cheap and cheerful and they work.

https://www.ebay.com/itm/8mm-Motor-Fuel-Primer-Bulb-Marine-Fuel-Pump-Hand-Primer-Gas-Petrol-Diesel-Pump/291595877217?hash=item43e477fb61:g:GFUAAOSwoRBaXvdd&vxp=mtr


Steve

Present
1937 60 convertible coupe
1941 62 convertible coupe
1941 62 coupe

Previous
1936 70 Sport coupe
1937 85 series V12 sedan
1938 60 coupe
1938 50 coupe
1939 60S
1940 62 coupe
1941 62 convertible coupe x2
1941 61 coupe
1941 61 sedan x2
1941 62 sedan x2
1947 62 sedan
1959 62 coupe

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #11 on: February 17, 2018, 06:31:27 PM »
I found even the 50 watts gets hot so I don't think that 40 will be any good, besides he doesn't state what ohms it is. This is where it came into trail and error with mine. Too many ohms and now power gets to the motor. Too few and the resistor makes no difference. Bruce can probably tell you how to check what your motor pulls in watts? The later motors are probably more powerful than mine.

The light relays will work but I have never fitted them to any of my conversions. Not really necessary as fewer amps in 12 volt.

Wiring connections are no different.

I was referring to fitting an electric fuel pump near the tank, not removing your original.  Seems too simple but I have fitted these on several cars with great success. Fit them down in the hood and you just prime up the carb manually. Cheap and cheerful and they work.

https://www.ebay.com/itm/8mm-Motor-Fuel-Primer-Bulb-Marine-Fuel-Pump-Hand-Primer-Gas-Petrol-Diesel-Pump/291595877217?hash=item43e477fb61:g:GFUAAOSwoRBaXvdd&vxp=mtr

Steve, I REALLY like your manual hand pump idea -- it goes between the mechanical fuel pump and the carb, right?

That said, more than likely I should go with an electric in-line pump. It sounds like you're doing a secondary, auxillary, mini-pump...is that right? If so, do you have a make/model that you recommend? (or a sizing) also, what trigger do you use for the power source? do you have a secondary on/off button?
1947 Cadillac Series 62 Sedan

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #12 on: February 17, 2018, 06:41:37 PM »
Bruce,
I am pretty sure I can figure out how to test out the draw on my heater motor...my next question is: once I know the draw (in amps), how do I translate that into what resistor should I buy?
Thanks
-Justin
1947 Cadillac Series 62 Sedan

Offline bcroe

  • Posts: 3895
PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #13 on: February 17, 2018, 08:24:07 PM »
Quote from: revvies
      Bruce,
I am pretty sure I can figure out how to test out the draw on my heater motor...my next question is: once I know the draw (in amps), how do I translate that into what resistor should I buy?    Thanks   -Justin   

Here are my views of the problem.  If you measure the current of the 6V
motor, simple ohms law V = I X R will allow calculating an equivalent
resistor on the first try.  Multiplying the V X I will give the watts of heat,
but many of us recommend running a considerable margin for trouble
free service.  Note, those metal resistors with the tabs are designed to
be thermally connected to a decent heat sink to approach their rating. 
Hot air in the engine compartment is reason to derate.  A ceramic type
will take a lot of heat, but may operate so hot it will melt wires that
come in contact with its body. 

With a resistor in place the blower on high may run fine at half battery
voltage.  But when you switch in resistors for low blower, current drops
and the voltage across the resistor you added DECREASES.  That
means the blower circuit will see INCREASED voltage above normal
limits.  The motor speed will be higher than before, and the speed
limiting resistor (often placed in the blower air stream) will see more
current/voltage. The POWER to this resistor goes up as the square
of voltage, so the power increase can be substantial, and these resistors
may burn out sooner from the elevated temp. 

In addition the above takes the heaviest circuit in these old cars, and
doubles the amount of load on the alternator. 

A LINEAR voltage regulator can maintain the correct output voltage
at all times, but is just as hot and inefficient as the resistor. 

You can cancel all the above problems by using a SWITCHING
style (buck) DC converter, which will produce exactly the voltage
you set with very high efficiency.  These have become very cheap
barefoot lately, all these run Pos in Pos out.  But they have a couple
new problems.  One is the radio interference that may get into your
AM radio.  By containing them in a hardware cloth box (very large
screen with cross points soldered) and use of at least a radio
suppression cap at input and output, noise can be contained. 

The other issue is the sensitivity of electronic supplies to high voltage
spikes.  Anything with contacts (horn, starter, blower) can generate
spikes up to dozens of times the basic voltage.  These spikes are in
the microsecond length, too narrow to bother things like light bulbs. 
But they can blow through transistors, as I found out in 1969.  The
fix is a simple protection network at a converter port, maybe a 500
microfarad 100V cap and a 20V transorb.  Radios and such already
contain the needed filters. 

One more thing about buck switching converters.  If the power element
shorts out, the input voltage may appear at the output, with possible
serious load damage.  There are CROWBAR circuits sometimes used
to assure the load won't be damaged. 

Gauges can have similar voltage regulation problems with resistors,
cured with a regulated supply.  Gauges sensitive to polarity are a
bigger problem, polarity changing supplies are available at higher cost. 
Bruce (building buck converters since 1967) Roe

Offline jackworstell

  • Posts: 341
  • Name: J L Worstell CLC #7558
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #14 on: February 18, 2018, 09:48:36 AM »
Bruce

Please clarify "all of these run Pos in and Pos out "


Jack Worstell        jlwmaster@aol.com

Offline bcroe

  • Posts: 3895
PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #15 on: February 18, 2018, 11:08:13 AM »
Quote from: jackworstell
   Bruce
Please clarify "all of these run Pos in and Pos out "
Jack Worstell        jlwmaster@aol.com   

In haste I meant, the latest crop of cheap (and quite efficient)
converters, the buck type, have only 3 terminals, a positive
voltage input terminal, returning to a negative voltage terminal,
and a positive voltage output terminal, also returning to the
shared negative terminal.  Works well here with the common
terminal tied to ground, but you can only convert a higher voltage
to a lower voltage of the SAME polarity, only positive to positive
for this group. 

There are converters (not buck) with 4 terminals (isolated
output) that will allow you to connect for any polarity arrangement
you want.  They are considerably more expensive.  Bruce Roe

Offline jackworstell

  • Posts: 341
  • Name: J L Worstell CLC #7558
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #16 on: February 18, 2018, 11:23:40 AM »
Thanks Bruce...I see now.


The last one I bought was two input terminals    and two output terminals   10A   max sustained    and 20A peak
for only  $20..       For what you get...these buck converters  are a bargain

These really help out when switching voltage and/or polariiy in an old car.

Jack Worstell

Offline revvies

  • Posts: 88
  • Name: Justin Norwood
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #17 on: February 19, 2018, 08:18:00 AM »
Thanks Bruce & Jack. I have to admit, after reading all of the limitations of resistors/VREG/etc. that rewinding the heater blower motor to be 12v compatible is sounding a lot more appealing. hmmmm....

-Justin
1947 Cadillac Series 62 Sedan

Offline bcroe

  • Posts: 3895
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #18 on: February 19, 2018, 10:13:30 AM »
Thanks Bruce & Jack. I have to admit, after reading all of the limitations of resistors/VREG/etc. that rewinding the heater blower motor to be 12v compatible is sounding a lot more appealing. hmmmm....  -Justin 

That is a mechanical challenge I would be afraid to try.  But if you
get it done, the variable speed resistors will also need to be changed
out, to about 4 X the 6V resistance.  Bruce Roe

Offline Bobby B

  • Posts: 2732
  • Mendham, New Jersey
  • Name: Bob Bender
Re: PARTS LIST: 6v to 12v conversion for 1947 Caddy (+ electronic ignition)
« Reply #19 on: February 19, 2018, 07:10:12 PM »
Thanks Bruce & Jack. I have to admit, after reading all of the limitations of resistors/VREG/etc. that rewinding the heater blower motor to be 12v compatible is sounding a lot more appealing. hmmmm....

No rewinding needed. There's a 12V compatible motor for your car that fits nicely to replace the existing 6V one. I have three of them in my '47.  Under-Dash Blower and the 2 Underseat Heaters.
                          Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

 

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