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Re: Need Help - Coil voltage values?
Posted by: gregb ()
Date: July 04, 2018 06:13AM

I have three coils here all clearly marked "12 Volts" and they all measure about 1.5 ohms and printed on the side of them it says to use with external resistor. I have a Bosch coil with no markings at all and it measures 3.3 ohms and a Flame Thrower that's marked .6 ohms. Ones needs to measure to be sure.

Gregb

Alberta Canada
61 Canadian Lakewood
62 Spyder Triple Black Convertible
65 Corsa Coupe

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Re: Need Help - Coil voltage values?
Posted by: BobV66Vair ()
Date: July 04, 2018 06:29AM

The coil measures 1.5 ohms across the + and -. Sorting out the comments, I think that's correct and should be fine. It does run well so I think I need to move on to the next thing! Those darn dash lights. Thanks for all the input. BTW, I did buy a new 12v coil that is specified for a Corvair and it ran and measured just the same.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 04, 2018 02:45PM

AHH marked "use with ext. res."

The Bosch needs 12 volts.. 3.3 ohms





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Edited 2 time(s). Last edit at 07/04/2018 02:46PM by MattNall.

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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 04, 2018 02:49PM

AHH 0.6 ohms... Why the flamethrower is spec'd for the Pet.





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 04, 2018 02:54PM

JimBrandberg Wrote:
-------------------------------------------------------
> I think oldqmguy is correct in what he's saying.
> With points and condensor ignition, you want to
> add up to about 3 ohms, usually about half from
> the coil and half from the wire or ballast.
> I keep forgetting to get another ohm meter, I
> plan to get one at Harbor Freight. the one I had
> seemed to need a battery every time I went to use
> it. I went to my usual auto parts with some coils
> and they let me use their meter. If your coil is
> roughly 1.5 leave the resistor wire, if it is
> roughly 3.0 bypass the resistor wire.
> MattNall could very well be correct about the
> markings, I don't know.
> I've never checked voltage at the coil with the
> engine running. With the rapid pulsing, is it hard
> on the volt meter?
> I guess I'm not really adding content, just
> trying to verify my understanding.
> Jim Brandberg
> Isanti, MN
> CorvairRepair.com

======================================

Actually you want an Analog meter for that.. digital gives you instantaneous readings.

So..

A Pet I or II

Flamethrower 0.6 coil on 12 / full voltage... HOT spark!

No wonder my Turbo never misses..





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Need Help - Coil voltage values?
Posted by: 66vairman ()
Date: July 04, 2018 02:59PM

Flamethrower coil 0.6 ohms is ONLY compatible with the Petronix Ignitor II.

If you use it with points or a Petronix I, neither will last long.

Also the 0.6 ohm Flamethrower is not to be used with a ballast.

I got a call from a club member who installed a new Flamethrower coil per one of the "experts" and the club memeber said he smelled a hot "electrical" odor. The "expert" had the club member install a 0.6 ohm Flamethrower coil in a stock system and the ballast resistor was VERY hot causing a smell. I put the stock coil back in and found the real problem and the car ran fine.

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Re: Need Help - Coil voltage values?
Posted by: red monza ()
Date: July 04, 2018 07:11PM

Your question was about coil VOLTAGE...
66 Corvair 140/pg......idling.....pos 10.8, neg 8.6 volts
49 chevy 283...........idling.....pos 9.5, neg 6.4 volts

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Re: FlameThrower II coil 0.06 ohm primary
Posted by: MattNall ()
Date: July 04, 2018 07:44PM

66vairman Wrote:
-------------------------------------------------------
> Flamethrower coil 0.6 ohms is ONLY compatible with
> the Petronix Ignitor II.

=====================================================
Are you sure?

[pertronix.com]





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Need Help - Coil voltage values?
Posted by: joelsplace ()
Date: July 05, 2018 10:09PM

With the vehicle running my '63 shows 12V at the coil through the resistor wire. I'm sure it depends a lot on the meter you are using and it really isn't useful information anyway.

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Re: Need Help - Coil voltage values?
Posted by: Gregory_Miller ()
Date: July 06, 2018 09:12AM

If you disconnect the points wire leaving the "-" side of the coil with nothing connected to it, and turn the key on, with any voltmeter you can check thew voltage to the coil while running by grounding he - lead of the meter, connecting + lead to + side of coil, which will read battery voltage at the moment. then briefly ground the "-" side of the coil with a piece of wire and if the value on the meter changes significantly, there is a resistance in the circuit either a physical ballast resistor or a resistance wire. Don't leave it grounded too long and you will get a single spark when you release the ground lead, so be prepared for that. Also disconnect power to Pertronix if your vehicle is equipped during this test.

Greg Miller
Eugene, Oregon

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Re: FlameThrower II coil 0.06 ohm primary
Posted by: 66vairman ()
Date: July 06, 2018 10:21AM

MattNall Wrote:
-------------------------------------------------------
> 66vairman Wrote:
> --------------------------------------------------
> -----
> > Flamethrower coil 0.6 ohms is ONLY compatible
> with
> > the Petronix Ignitor II.
>
> ==================================================
> ===
> Are you sure?
>
> [pertronix.com]
> t.aspx

I was referring to Petronix equipment. It does say to use with Petronix II, or other "high energy system". So yes the Flamethrower II is compatible with "other" systems with little specifics as to "other".

At 0.6 ohms the Flamethrower II amperage exceeds the Petronix guidelines for the Petronix I Ignitor even with a ballast resistor. Then again Petronix guidlines seem to be deliberately vague. Probably the source of so many complaints about Petronix problems.

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Re: Need Help - Coil voltage values?
Posted by: 66vairman ()
Date: July 06, 2018 10:33AM

The posting of "coil voltages" when the engine is running are not an accurate reference using a Digital meter.

In the old days some shops used oscilloscopes to check ignition systems

When the engine runs and the points (or electonic switch) open and close an oscilloscope would show what is a basic square wave with a high voltage of about 14 and and a low voltage of about 6 volts on the "+" terminal. Some meters will attempt to integrate these into an "AVERAGE". Depending on the dwell, meter design, etc. you'll get an approximation of about 10volts. The "-" coil terminal will be about 7 volts.

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Re: Need Help - Coil voltage values?
Posted by: jjohnsonjo ()
Date: July 06, 2018 05:26PM

66vairman Wrote:
-------------------------------------------------------
> The posting of "coil voltages" when the engine is
> running are not an accurate reference using a
> Digital meter.
>
> In the old days some shops used oscilloscopes to
> check ignition systems
>
> When the engine runs and the points (or electonic
> switch) open and close an oscilloscope would show
> what is a basic square wave with a high voltage of
> about 14 and and a low voltage of about 6 volts on
> the "+" terminal. Some meters will attempt to
> integrate these into an "AVERAGE". Depending on
> the dwell, meter design, etc. you'll get an
> approximation of about 10volts. The "-" coil
> terminal will be about 7 volts.


X2, thanks for posting, I was about say what you just did, but then thought it might just make it more confusing to some.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 06, 2018 05:28PM

Guys!! Go back I mentioned that earlier!!





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Need Help - Coil voltage values?
Posted by: CoCoCo ()
Date: July 09, 2018 08:14PM

All this talk of coils and resistance got me curious. And because you guys seem to know theory and the be-all, what-all, why-all and wherewithall about such stuff, I'm wondering what all the resistance stuff is for in the first place?

I always thought (assumed, really) that it was simply to lower the voltage to a component designed to run properly in older 6v systems. And might overheat and fail when exposed to higher voltage for extended periods.
But that is not correct, correct?

It's somehow important to total a certain amount of resistance when using standard triggers then, but not modern high-efficiency electronics? Hence the .6 low resistance for some new stuff?

I always thought more voltage meant a hotter spark if the coil could handle it. Hence coils with the ability to handle it. But through more internal resistance, wouldn't that just lower the output power again?

Anyway, sorry for the semi-hijack. Just wanted to know in a nutshell (if that's possible) why all the resistances and bothering with resistor wires when they could have just used a 3 ohm coil in the first place!

Thanks
And if there's a good thread that describes the theory behind it all, I'll be happy to read it.

Paul

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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 09, 2018 08:34PM

Paul, because they were using points AND Carburetors...!!

Points will burn even with the proper value condensor....

Carburetors? They made engines hard to start in COLD climates / Mornings as well as Hot restarts...

Simple use of the starter's solenoid as a relay to feed 12 vdc for just the period of Cranking, allowed the use of a Cheap coil!





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Need Help - Coil voltage values?
Posted by: oldqmguy ()
Date: July 09, 2018 08:43PM

The original "Kettering Ignition" was designed for cars that used a 6 volt system.

My "theory" has always been that the manufacturers had large stocks of 6 volt coils when they changed to a 12 volt system. They figured out that it would save money by using a Resistor so they could use the stock coils instead redesigning and buying "12 volt coils!" This also allowed them to 'invent' the "extra spark while starting' feature!!!

Remember, this is" MY" opinion! I have no proof one way or the other! I am sure "they" will deny it.

It just seems to make sense to me!

Dale cool smiley

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Need Help - Coil voltage values?
Posted by: gregb ()
Date: July 09, 2018 09:19PM

I believe the reason is to limit the average current through the points to give a reasonable life span. The higher the current the more quickly the points will burn up. Approx 3 ohms is needed for a 4 or 6 cylinder engine and 1.5 ohms for a 8 cylinder.

Gregb

Alberta Canada
61 Canadian Lakewood
62 Spyder Triple Black Convertible
65 Corsa Coupe

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Re: Need Help - Coil voltage values?
Posted by: oldqmguy ()
Date: July 09, 2018 10:10PM

Actually, the amount of resistance needed depends on the design of the Ignition System. It has nothing to do with the number of cylinders.

The original 6 volt system was designed for a specific amount of current in the Primary to produce a given high voltage from the Secondary. This took into consideration the amount current the coil could live with and the points could handle for a reasonable length of time.

Other Ignition System designs call for different values. In order to use a "6 volt coil" in a 12 volt system a Resistor or 'Resistor Wire' is necessary to avoid excessive current through the coil and points.

We need to understand the system we are working with and use the proper parts.

Changing parts without understanding how it will affect the rest of the system is dangerous!

I hope this helps!?

Dale cool smiley

Dale E. Smiley CPBE
Life Member The Society of Broadcast Engineers
RETIRED Broadcast Engineer
CERTIFIED CORVAIR NUT
CORSA/Circle City Corvairs/Corvair Performance Group
Avon, Indiana
WB9SFF
1967 4-Door Monza PG!

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Re: Need Help - Coil voltage values?
Posted by: MattNall ()
Date: July 09, 2018 10:16PM

Dale... what would make it "dangerous"





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Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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