The Ford Barn

The Ford Barn (https://www.fordbarn.com/forum/index.php)
-   Model A (1928-31) (https://www.fordbarn.com/forum/forumdisplay.php?f=3)
-   -   Pertronix 40111 6V 1.5 ohm (https://www.fordbarn.com/forum/showthread.php?t=217849)

mshmodela 04-01-2017 06:38 AM
Pertronix 40111 6V 1.5 ohm
 

Well appears the last around of rain has washed away the broad salt and I have a pertronix 40111 1.5 ohm 6V coil --epoxy filled to try out (suspect my oil filled coil might be my intermittent issue). With this coil, I believe it has a higher output voltage and would my spark plug gaps need changing? I have a standard head (compression wise)

https://m.summitracing.com/parts/pnx...DBMaAqC88P8HAQ

MikeK 04-01-2017 09:22 AM
Re: Pertronix 40111 6V 1.5 ohm
 

Your gap stays the same. Expect your points to burn up in short order with twice the amperage across them. Your link shows an oil filled coil.

Chuck Sea/Tac 04-02-2017 01:04 AM
Re: Pertronix 40111 6V 1.5 ohm
 

Quote:
Originally Posted by MikeK (Post 1451302)
Your gap stays the same. Expect your points to burn up in short order with twice the amperage across them. Your link shows an oil filled coil.
What if you don't have points?

Mike V. Florida 04-02-2017 02:52 AM
Re: Pertronix 40111 6V 1.5 ohm
 

Quote:
Originally Posted by MikeK (Post 1451302)
Your gap stays the same. Expect your points to burn up in short order with twice the amperage across them. Your link shows an oil filled coil.
https://m.summitracing.com/parts/pnx-40111

MikeK 04-02-2017 08:14 AM
Re: Pertronix 40111 6V 1.5 ohm
 

Quote:
Originally Posted by Chuck Sea/Tac (Post 1451619)
What if you don't have points?
You need to make sure your transistor ignition module is capable of (1) switching the peak amperage and (2) dissipating the resultant heat generated by the semiconductor voltage drop. The killer of ignition modules is generally #2. That heat is a function of the dwell times the number of cylinders divided by 360 then multiplied by the heat (watts) calculated by the amperage times the semiconductor voltage drop.

Doubling #1, the switching amperage, easily done by simply going from a 3 ohm to a 1.5 ohm coil, will instantly double the heat. That is why pertronix ignitor modules are NOT recommended for use with low ohm coils. They will fail, usually somewhere inconvenient, like on an elevated interstate cloverleaf with no shoulders.

A standard pertronix ignitor module (the black ones) will burn up in less than 20 minutes if you leave the key on with the switching closed (reluctor not rotating, equivalent to points closed) with a 1.5 ohm coil. You have effectively driven the dwell to max and the heat builds faster than it can dissipate.

If you want any sense of reliability with the 1.5 ohm coil use the ignitor II (red color, 12V only!) module.

katy 04-02-2017 10:28 AM
Re: Pertronix 40111 6V 1.5 ohm
 

I was under the impression that 1.5 ohms (more or less) was the preferred resistance for a 6 volt coil? And 3 ohms for a 12 volt unballasted coil?

Patrick L. 04-02-2017 01:58 PM
Re: Pertronix 40111 6V 1.5 ohm
 

Quote:
Originally Posted by katy (Post 1451746)
I was under the impression that 1.5 ohms (more or less) was the preferred resistance for a 6 volt coil? And 3 ohms for a 12 volt unballasted coil?




Yep.

One wants only 6v to the points regardless of battery voltage. [ no more than 8v with 12v battery]

So, the Pertronix 40111 is 1.5 ohm and epoxy filled. If 12v was to feed this coil a ballast resistor would be needed.

Thats my take unless I'm missing something.

And, to the original question. the sparkler gap can remain the same. .035"

Bob Bidonde 04-03-2017 08:34 AM
Re: Pertronix 40111 6V 1.5 ohm
 

I ran a Pertronix 40611 Coil with 12V for 200 plus miles without any abnormal degradation of the stock ignition points.

Patrick L. 04-03-2017 09:14 AM
Re: Pertronix 40111 6V 1.5 ohm
 

Quote:
Originally Posted by Bob Bidonde (Post 1452209)
I ran a Pertronix 40611 Coil with 12V for 200 plus miles without any abnormal degradation of the stock ignition points.



I believe the 40611 is a 3ohm coil so no external resistor is needed with 12v.


All times are GMT -5. The time now is 05:50 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.