converting 1952 Buick Special to 12V.

currently in mid conversion and want to keep the foot pedal start. Where does the wire16GC from the Gen post of the original voltage regulator go since I have eliminated the Gen and Field wires from the old Generator? Generator was replaced using a one wire 12V alternator (looks like the old generator but is an alternator with internal voltage regulator).

This wire runs from the Gen post on the voltage regulator to the starter relay on the firewall.

Also, the conversion (vintage auto) states not to use the original Ammeter. Any truth to this? If so, do I bypass it by hooking both wires up to one post on the back of the gage?
 
In my 1940 Shop Manual, the 16GC circuit connects the regulator to the starter Battery terminal. (I'm pretty sure, but the manual is a reprint, and my glasses were way up on my forehead.) The starter switch on the carb picks up 14 amp fused power (with ignition On) and when closed (pedal on the metal) to start, feeds the S terminal of the starter solenoid. I think that relay on the firewall is a horn relay. If that's a good guess, the B terminal will have battery power, picked up at the starter. I took a 263 from a 52 Special and installed it in my 40 Special, so, although I've been around that block, it was in the 1980s. I don't think these Buicks used starter relays. (Just heavy wire) So your basic foot pedal start wiring would be ignition switched and fused supply line to the starter switch on carb, and from carb switch other terminal to the starter solenoid S terminal. I hope that helps. I don't know why using the original ammeter is prohibited, never having used a one wire alternator. But the original ammeter works fine with the three wire 12 volt GM alternator in my 53 Pontiac. The proposed bypass makes sense to me, but leaves you with no ammeter.
 
It is the starter solenoid relay as it states on the wiring diagram from this site. The horn relay is on the left side of the radiator. I assume the wire from the Gen connector on the voltage regulator puts voltage on the starter relay so that when you mash it full throttle-the starter doesn't kick in though I am not sure. Any thoughts?
 

suntreemcanic

Active Member
I converted my 52 to 12 volt. I retained my foot start. The two wires going to the switch on the carburetor, one comes from your ignition switch, on position and the other goes to your starter relay on the firewall under the wiper motor. The change of voltage does not effect these two wires.
 

suntreemcanic

Active Member
I used my original amp meter. I think what they were concerned about if you use a high output alternator the gauge could not handle all those amps. I use a low output alternator, 42 amp and the amp gauge works perfect. I think the original generator was about 40 amp. My 42 amp alternator will run both heaters, the head lights on bright and a modern radio all night long because my wife and I have done it. With that 12 volt output you can also hook up all the modern electronic tools and toys.
 

firstofeight

Active Member
I don't have a wiring diagram in front of me. I believe the wire you are asking about is the STARTER RELAY ground from the generator. This circuit was/is a safety to keep the starter from engaging while the engine is running. It grounds the starter relay UNTIL the generator begins charging at which time the ground is broken and the relay is then not grounded, rendering it inoperative. Your alternator likely does not have this circuit. If this is correct, grounding the wire will allow the starting system to function. Will also allow it to operate while engine is running if vacuum drops low enough, as at wot, if the " push to start " switch on the carburetor is still being used. I use a push button.

On the amp meter, suntree is correct. I am using a higher output alternator. I disconnected the amp in wire and connected it to the out post on the amp meter, thereby bypassing the meter.

Ben
 
currently in mid conversion and want to keep the foot pedal start. Where does the wire16GC from the Gen post of the original voltage regulator go since I have eliminated the Gen and Field wires from the old Generator? Generator was replaced using a one wire 12V alternator (looks like the old generator but is an alternator with internal voltage regulator).

This wire runs from the Gen post on the voltage regulator to the starter relay on the firewall.

Also, the conversion (vintage auto) states not to use the original Ammeter. Any truth to this? If so, do I bypass it by hooking both wires up to one post on the back of the gage?
That wire which comes from the ground side of the solenoid in my 41 special finds ground through the armature of the generator in a non-running engine. Once the engine starts, and the generator begins to charge, that terminal is at b+ potential. This acts as a fail safe in addition to the vacuum port on the start switch preventing accidental engagement of the starter in a running engine. The 52 may have added a start relay but the principle should IMHO be the same. Ground that wire and you should be good
 

suntreemcanic

Active Member
I still learn something about my Buick. I did not know about the starter relay grounding through the generator. Those old Buick engineers were thinking of everything. I did my 12 volt conversion 30 years ago and I do not remember re- locating the ground wire for the starter solenoid. I do know I never had the starter to engage when putting the throttle to the floor creating a low vacuum situation. I must of been lucky. I have removed the straight eight and installed a nailhead now. I am using a push button start but the pedal start is still in my plans but now it became more complicated after I learned about the starter relay ground protection system.
 
Yeah, these old Buicks sure are educational toys. I don't understand about "the ground side of the solenoid". I'm thinking starter solenoid, but since it has only the battery terminal, the starter terminal and the switch terminal, it can't be that. Please enlighten me.
 
Like I said this applies to my 41. It is very likely that gm went to a remote relay that energizes the starter relay in later years, I just don’t know. That would have enabled them to use a similar starter solenoid across the brands. But if they did, i would suspect that the ground side of the added relay might go through that circuit I mentioned.
 

suntreemcanic

Active Member
I am only familiar with 52s but the starter relay is on the firewall about 12 inches above the starter. It looks exactly like the horn relay.
 
The stand alone solenoid relay mounted on the firewall was introduced sometime early in the 1942 model year. Earlier models have a solenoid relay too. It is mounted on the solenoid down on the starter. Operation and wiring hookup is alike on both types.

The 1942 Shop Manual discusses both types and refers the reader back to the '41 manual for service on the built-in solenoid relay. See attached page on the built-in relay.

The 16GC wire that went to the generator armature terminal could be rerouted to a maintained toggle switch somewhere within reach of the driver. This switch would ground the solenoid relay coil return wire in normal operation. If something goes haywire causing the starter to engage improperly, the switch would be used to kill the starter circuit. By mounting the switch in a hidden location, it would also make a dandy anti-theft device that prevents the engine from starting.
 

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Oops... I misread the '42 Shop manaul. The Solenoid Relay received a new part number that year but was still mounted on the starter. The stand alone relay was not introduced until the 1951 models.
 
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