The Stovebolt Site Forums The Shop Area Engine Shop What volt coil?

Is the ignition coil on a 1952 235 engine a 6 or 12 volt?

If the engine is to be installed in a 1952 vehicle that has the original electrical system: 6 volt.

Dumb question here... if you put in a twelve volt coil I would assume there is no chance of creating spark correct? I ordered the wrong coil obviously.

Coils develop spark by creating a magnetic field around thousands of turns of very fine wire, then collapsing the magnetism to create the high voltage. The 12 volt primary winding would have a limited current flow due to high resistance, resulting in a very weak magnetic field. You would get a weak spark, if there was any at all, running the coil on 6 volts.
Jerry

Simple question would be which battery do you have in the truck ?

I have a 12 volt battery in the truck. I know there is a resistor before the coil so with a 12 volt coil with what you are saying would mean no spark. Never had anyone explain to me actually how a coil works. That makes sense now. I appreciate the help. I changed it to a six volt coil today but I have not had a chance to try and start it. but the battery advice would help as well.

The "12 volt" coil actually operates on about 9 volts. That's the voltage that's available during cranking with a very cold, or very hot engine due to the load the starter puts on the battery. The resistor you mentioned reduces the voltage to the coil during normal running when the starter isn't operating. There is supposed to be a circuit that bypasses the resistor while cranking to allow full battery voltage to go to the coil, then reduce the voltage when the starter is not running.

Using a 6-volt coil with a 12-volt battery will burn out the points in a matter of minutes, even if the resistor is in the circuit.
Jerry

So I should get a six volt battery then?

No.

The main issue is I'm a young whipper snapper who has built motorcycles and worked on newer cars and trucks. The whole six volt system is throwing a wrench in the mix. I don't understand why I cant get a grip on it haha. I may be making it more complicated than it is.

Another thing I'm unsure of is about the negative or positive ground at the battery. I have a red battery cable going to the frame and a black to the engine. Is the red still the positive cable? I feel reel dumb here ha.

Are you running a Chevrolet or a GMC chassis? Chevy 6-volt systems used negative ground electrics, GMC used the positive ground system like most big trucks did. Look at the battery posts, not the color of the cables. If the larger diameter of the two posts is connected to the frame, the system has been set up as (+) ground. That may, or may not be right.

Does the rig have a generator or an alternator? If it's set up for an alternator, it needs to be negative ground, as there are very few (+) grounded alternators. A generator can be polarized either way, but I'd still reccomend going with negative as the ground polarity. It sounds like you need to spend a considerable amount of time learning about electrical systems, or find someone to help you who knows what he's doing. It only took me 10 years or so of working on these systems before I got really comfortable around them, and our family shop was the best one in Middle Tennessee where electrical work was concerned.
Jerry

Chevrolet should be negative ground, GMC is positive ground.
On a side note, I've seen a 6 volt coil explode from too much voltage. Granted, it had 48 volts going to it at the time (not my idea). Didn't do the starter any favors either. If you're wondering, the coil was off a '50 Chevy, installed on a '29 Buick Marquette, and was being jumped by 4 12 volt Delco marine batteries. As mentioned, it was not my idea, they guy dong it though "hey, if 12 will turn it over this fast, 48 should really whip it over". I'm not sure which was funnier, the exploding coil, or the melting (yes, melting) starter windings.

WOW! LONGBOX55 thats a story there. I wish I would have been a fly on the wall for that one. Jerry I do agree I have a lot to learn with electrical. I have only had to learn much on electrical with motorcycles and thats a piece of cake for just about anyone. Most electrical stuff on a bigger scale I have messed with has been common sense stuff. Its a chevrolet chassis with a generator. Would it be easier to switch to a twelve volt system? Or take the time to learn about the 6 Volt?

I think you should
1. figure out what you have
2. if it is correctly put together before you go buying a bunch of stuff sticking it in and further confusing yourself.

TO start
do you have a factory manual and
a WIRING DIAGRAM ??
What is factory design?
IS factory design what you have?
do you have an alternator or a generator?
Do you have 3 cells (6 volt) or six cells in battery (12 volt).

IF 12 VDC then you need to figure out coil circuit. These came in two flavors
12 VDC coil and a 6 VDC coil with a dropping resistor. Resistor was bypassed during cranking to deliver hotter spark. During run resistor was in circuit so coil ran at 6 VDC.

Dan Bentler

Read the tech tips here .
http://www.stovebolt.com/techtips/12_volt_conversion.html

Joshua,

Since my truck is not concours and will never be, switched to 12v many years ago and never looked back. Had to put a step down resistor up river of the fuel gauge, swapped the generator for an alternator, etc but the beast has ran and cranked over with lots of umph!

The tech tip's 12 volt conversion article is good stuff to read if you choose to go this direction.