1955 electrical help

[EricV216]

Hey everyone I’m hoping to get some help.  I’m new to these Buicks and just purchased a 1955 Century 2 door.  The previous owner did an alternator conversion and removed the pedal start by adding a push button on the bottom of the dash. And messed with the wiring coming out of the firewall. I got the engine running by jumping from the ignition coil resistor straight to the coil but I know this is not correct and I need to sort this out. 
 

The wiring I’m looking at are as follows:

 

On the center/passenger side of the firewall there is one pink and one yellow wire coming out of the firewall and going directly to what I believe is the ignition coil resistor.  Yellow on one side and pink on the other.  The pink wire is the hot source when the key is turned to on.

 

On the center/driver side of the firewall there are two yellow and one pink wires coming out.  All three of these wires have been cut.  One of the yellow wires has a piece of wire added with a ring terminal, presumably the wire he used to go to the + coil.  I’m trying to figure out what these three wires originally connected to.

 

The pedal start has been disabled and to an extent removed from the car which isn’t a big concern to me right now but I don’t know if the removal of some parts is affecting the ignition wiring.  These are my findings so far:

 

To start, the start push button the previous owner added is wired from the powered junction block on the driver fender to the dash/button then directly to the starter.  The large power wire for the starter goes from this junction block directly to the starter (this power cable appears to be how the wiring diagram describes).  The yellow wire going to the starter has been removed and I’m yet to even find it on the car. 
Additionally, I cannot locate a starter relay anywhere on the car as the button is directly wired to the starter, presumably in place of the relay.

I also cannot locate the accelerator switch, between the starter relay and the neutral safety switch, which I believe has also been removed along with the starter relay, effectively disabling the neutral safety switch.  

 

 I’m hoping that someone can help with sending me some close-up photos of the wiring on the firewall around the back of the motor and leading to the coil, the starter relay, etc that I mentioned.  I’ve been going through the writing diagrams but am having some trouble figuring out exactly what he did.  I’d ask him but he has passed and his grandson didn’t know much about the car.  I can usually figure these things out provided I have a correct example to reference.  
 

I’m more than happy to provide my phone number or email address to anyone that’s willing to help.  Thanks.

Edited October 3, 2023 by EricV216 (see edit history)

[old-tank]

Here is a start until you get a service manual.

[EricV216]

I have one.  But I’m struggling finding these wires in the car and figuring out what has been removed.  At this point I believe the pink wiring coming out of the firewall center/driver side should go to the starter relay, one of the yellows goes to the coil, and the other yellow bo idea yet.

Edited October 3, 2023 by EricV216 (see edit history)

[buickbrothers]

I have a 55 Roadmaster Sedan - not a 2 door Century. I just battelled all the wiring with the help of forum members to get the accelerator start to work. If yours is like mine, there are safety features that don't allow the car to start via the accelerator pedal due to the carburetor vacuum switch and the generator safety features along with the neutral safety switch wire. You really need a shop manual to read through all this if modifications have been done that altered/removed multiple contact points. OldTank sent the wiring spec. I'll take some more pic's and send tomorrow. As a start, there is a pink and yellow wire coming out of the firewall that goes to the carburetor vacuum switch that controls the accelerator pedal start. It's vacuum controlled where it moves a ball bearing to the correct position to make contact between the two wires for the starter to engage. Has this also been removed? If so, then you have multiple things to hook back up to use the accelerator start capability.    

 

[JohnD1956]

29 minutes ago, buickbrothers said:

As a start, there is a pink and yellow wire coming out of the firewall that goes to the carburetor vacuum switch that controls the accelerator pedal start. It's vacuum controlled where it moves a ball bearing to the correct position to make contact between the two wires for the starter to engage.

This description is not quite accurate. The switch on the carb has a ball bearing in it and when there is no engine vacuum the ball bearing rests between a cam (like a fuel pump cam) in the base of the carb and a plunger in the switch so that when the accelerator is pushed the cam pushes the ball bearing and plunger assembly to make the electrical connection between the two contacts in the cap of the switch.  When the engine is producing vacuum, the ball bearing is pulled out of place so it no longer contacts the plunger and the plunger cannot be operated to make that connection.  This is one of the failsafes to prevent the starter from becoming engaged while the engine is running.  The other failsafe I still do not totally understand but if I have this right, the starting circuit is actually grounded thru the field of the generator. Thus when the generator begins to produce electricity that ground is broken and the starter won't operate if the 1st failsafe fails. 

The car in question has been modified with an alternator so the 2nd failsafe no longer exists along with no ground for the starter system. And if the 1st failsafe is no longer there then that would cause a vacuum leak. But there is just a few variables which we cant tell like is it even a correct carb with the switch for the car?  

Some on here have talked about a workaround to employ the starter switch with an alternator modification but that is totally above my understanding too. 

In this case the question is for 55 guys. Where do the two wires on the passenger side by the distributor go? And where do the three wires on the drivers side of the distributor go?  

 

[buickbrothers]

Thanks JohnD56 for a better description. I've attached several pics for reference.

 

 

 

 

 

 

 

I'm throwing the generator pic in for reference although you have an alternator:

 

 

[EricV216]

I do have the repair manual and have been going through the wiring diagrams.  I was asking for the pictures to confirm the parts I believe were removed have in fact been removed.  Thank you for the photos so far.  
 

The car does have the correct stock carb and I also have a spare.  It still has the switch on the carb it’s just not connected.  Now I know for sure the yellow and pink wires coming out of the center/driver side firewall go to the switch.  When everything is back together I will test them disconnected and connected to the switch to see how it operates with the push button start.  It would be nice to have that fail safe work with the push button. 
 

The push button start is actually wired quite simple with the alternator conversion.  But I don’t want to post how it’s set up until I go test option to keep one fail safe.  Ive been thinking about using either the stock starter relay or a different GM one to prevent the starter from being able to spin when the engine is running but I’ll hold off for now until I test the stock carb switch.  
 

Now I’m just waiting for gaskets to show up next week so I can put the valley cover, intake manifold, valve covers and carb back on.  I will post my results when it all together.  Thanks for the help so far.  

[EricV216]

By the way Buickbrothers, I see you have a pertronix coil so I assume you’re running the pertronix ignitor.  I see you still have the resistor wired into the circuit.  The resistor didn’t drop the voltage too much I assume?  I haven’t tested mine yet.  I have been reading that the resistor may or may not need to be removed.

[buickbrothers]

Yes, and sorry, this pic is before I spliced the ballast wires together. Good catch. I'm using the lobe sensing 1181LS Pertronix. The 1181 with the magnetic ring is not considered good for our late type distributor per Centerville Auto. I bought my engine parts from them and I used them and tech notes as a guide for my engine rebuild. They have lot's of tech notes that I highly reading as you go through your car. They only work on Buick Nailheads. 

 

Home | Centerville Auto Repair (nailheadbuick.com)

[EricV216]

I’ve been reading all their tech notes and blog posts.  I didn’t see anything about removing the resistor but I may have missed that part.  Very good info on their site.  I also have the 1181ls and the flame thrower coil.  So no resistor got it.  

[buickbrothers]

Per the documentation, it doesn't really have to be removed. I was going with the description where it indicates you can obtain "optimal performance" of the ignitor system. Since the Flamethrower coil is 1.5 ohms, I removed ballast resistor. They don't really indicate what the performance difference is if you retain the ballast resistor, but they indicate you can per option "B" below. 

 

[old-tank]

Pertronix rant

[Machine Gun]

I decided to convert my Skylark to electronic ignition...just as soon as new points become unavailable. 

[EmTee]

21 minutes ago, Machine Gun said:

...just as soon as new points become unavailable. 

It's the crappy condensers being pushed these days that's more likely to drive your transition schedule...

 

 

 

[Machine Gun]

@EmTee Based on my limited research it seems that ignition capacitors have a value around 0.22uF. That's a common value in electronics, and I have a bunch of them in my parts store. Experimenting with ignition caps is another Winter project I have in mind. I would replace the innards of the can with a proper high-temperature, high voltage cap and see how it performs and holds up. 

[EmTee]

Yes, that's what I was thinking too.  There was a topic on the forum somewhere where someone else did that and apparently worked fine.

[60FlatTop]

2 hours ago, Machine Gun said:

I would replace the innards of the can with a proper high-temperature, high voltage cap and see how it performs and holds up. 

If I had concerns about point and condenser temperatures I would probably take the lead of V12 Jaguars. They have a intake vacuum connection that pulls filtered air through the distributor body.

Edited October 9, 2023 by 60FlatTop (see edit history)

[old-tank]

The capacitor can be mounted externally.  That way you don't need a cute little round one with a pig-tail.  And if there is failure it is easy to replace...also useful for testing purposes.

[Daves1940Buick56S]

13 hours ago, Machine Gun said:

@EmTee Based on my limited research it seems that ignition capacitors have a value around 0.22uF. That's a common value in electronics, and I have a bunch of them in my parts store. Experimenting with ignition caps is another Winter project I have in mind. I would replace the innards of the can with a proper high-temperature, high voltage cap and see how it performs and holds up. 

You are correct on the value. But the other value you need to consider is the voltage rating. The primary will shoot up to at least 40 volts on points opening, sometimes higher. I would add a very generous safety factor and get at least 200 WVDC. 400 WVDC would be even better. Otherwise you might get the Tow of Shame.

[Machine Gun]

@60FlatTop I'm not so concerned with temperature that I'd emulate any technique employed by the Prince of Darkness 😛. Capacitor temperature ratings up to 105 degrees C are standard. Higher ratings are available on special order, but if the environment the ignition capacitor finds itself in gets that high there are probably bigger problems I would have to worry about.

 

@old-tank Thanx for the tip on mounting the capacitor externally. I will do that for testing purposes. I like to think that I'd have come up with idea on my own but I wouldn't bet on it. As for re-stuffing a can, I will probably to that despite it being an unnecessary effort. On rare occasion I will re-stuff old radio capacitor cans during restorations. Whether I eventually do that here depends on the physical size of the replacement.

 

@Daves1940Buick56S I have capacitors on hand that are rated at 400V. If tests are successful I will order and install one rated at 600V. I have several 600V caps on hand, but not with the proper capacitance value.

[Daves1940Buick56S]

Ok you know the score then. I have a full bench setup to test distributors and I will do some testing myself. I think 400 VDC will be sufficient but it's always good to test to a full range.

[NorthernFirepower]

On 10/4/2023 at 9:41 PM, EricV216 said:

...Now I’m just waiting for gaskets to show up next week so I can put the valley cover, intake manifold, valve covers and carb back on.  I will post my results when it all together.

Well what's the score Eric? You have me on the edge of my seat. I'm vetting the starting and charging circuits on my '56 Super and found your thread useful. Don't think my '56 has the vacuum switch on the carb like your '55 thou.

[EricV216]

On 5/14/2024 at 6:00 AM, NorthernFirepower said:

Well what's the score Eric? You have me on the edge of my seat. I'm vetting the starting and charging circuits on my '56 Super and found your thread useful. Don't think my '56 has the vacuum switch on the carb like your '55 thou.

Sorry I never followed up. Everything works good.  The car has a 3 wire alternator so the stock generator and generator regulator have been removed.  The starter button that was added is working perfect and I did not end up messing with it.  My problem was figuring out which wires should go the the coil because they were anll disconnected and whether or not to use the resistor.  I’m not using the resistor but it is still mounted on the firewall with the pink and yellow wires attached to the same side.  I kept it just in case for some reason I needed it.  I connected the yellow wire that comes out of the driver side of the firewall to the coil.  Not sure if that answers your question.  

[EmTee]

7 hours ago, EricV216 said:

 I’m not using the resistor but it is still mounted on the firewall with the pink and yellow wires attached to the same side.  I kept it just in case for some reason I needed it.

The point contacts will degrade more quickly if you're running them at 12V without the ballast resistor in the circuit.

[EricV216]

On 10/4/2023 at 7:54 AM, buickbrothers said:

Thanks JohnD56 for a better description. I've attached several pics for reference.

 

 

 

 

 

 

 

I'm throwing the generator pic in for reference although you have an alternator:

 

 

As I was looking through this post again I noticed the generator has what looks like a capacitor/condenser wired to it.  Is that what that is and what is it doing, radio interference?  Does anyone use these on alternators?

[EmTee]

12 hours ago, EricV216 said:

Is that what that is and what is it doing, radio interference?  Does anyone use these on alternators?

Yes and no, not at the alternator.  Sometimes you'll see one at the (external) regulator.

[Joseph P. Indusi]

Just to clear up the accelerator starting system and the ways to prevent starter actuation when the engine is already running it is worth remembering the following:

 

There are two systems to prevent the starter from trying to start an engine already running:

 

One system is the starter switch on the carburetor.   Basically the switch will close when the engine is not running but once the engine starts, engine vacuum is directed to this switch to lift a ball (probably a small ball from a ball bearing) so that the switch cannot close.   The ball when the engine is not running is positioned so that the two contacts can touch when the accelerator is pushed but once the ball is not in position the contacts can never touch or close the switch.

 

The other system is the relay that that has contacts that need to close to actuate the starter solenoid.  The coil in this relay when energized closes these contacts.  Normally a relay has one coil end connected to +12 volts via a switch and the other end of the coil is connected to ground or -12 volts on a car with the battery negative connected to ground (the car frame and engine block).  However to prevent the relay from actuating the starter solenoid the relay end normally grounded obtains ground or -12 volts by being connected to the generator output or the GEN or ARM terminal on the generator or regulator.   When the engine is not running, this terminal through the brushes and commutator is basically grounded.   You can verify this with a digital or analog ohmmeter.  Just place one probe to the ARM or GEN terminal and the other to chassis ground.   You should read very close to zero ohms.  Now once the engine starts the GEN or ARM terminal goes to +12 volts so now the relay coil cannot close the contacts with + 12 volts on both coil terminals.   Note that the Field terminal plays no role in this.

 

A little long winded but if you read this while studying the wiring diagram above it makes sense.   Those Buick engineers were clever fellows as this system was used on some Buicks back in the 1930's.

 

Joe, BCA 33493