ballast Resistor?
Thread Starter
|
Senior User
Joined: Oct 2005
Posts: 253
Likes: 0
ballast Resistor?
I am swaping out my points for an electronic ignition. The question came up, why do I have a ballast resistor? Do I still need it with the electronic ignition? The auto parts place said that it depends on the coil. What is the deal?
BTW it is for a 337 flathead.
John - NNY
48 F-7
BTW it is for a 337 flathead.
John - NNY
48 F-7
Fleet Mechanic
Joined: Sep 2002
Posts: 1,622
Likes: 3
From: okla
I replaced the points in my 302 a few years ago with a Pertronix set up and did away with the ballast resistor. Later I saw where Pertronix suggests not to. I have left it out to date with no negative effect. This is in a street rod driven maybe 4000 miles per year. Will be interesting to see other responses.
Postmaster
Joined: Mar 2000
Posts: 3,730
Likes: 13
From: Waynesville, OH
Some points and coils can probably tolerate the higher voltage and current that comes with removing the ballast resistor. While the engine is running, the current is intermittent, i.e., the current only flows while the points are closed.
I'd be more concerned with having the ignition switch on and the engine stopped while the points happen to be closed. I know for sure this can be a BAD thing as I had it happen on a car a long time ago. I had removed the ballast resistor to get a hotter ignition spark (stupid young kid then) and was working on something on the engine. Well, the engine killed while I was under the hood, and I was busy for five or ten minutes. When I finally got back to the ignition switch and tried to start it, there was no spark. I finally traced it back to a set of points that were welded together.
When we're working on our trucks, I imagine there are quite a few times that, for one reason or another, we have the ignition switch on and the engine not running. I'm not sure I'd want the full battery voltage running continuously through the coil and points. On the other hand, maybe some brands of points and coils aren't bothered by the extra current.
I'd be more concerned with having the ignition switch on and the engine stopped while the points happen to be closed. I know for sure this can be a BAD thing as I had it happen on a car a long time ago. I had removed the ballast resistor to get a hotter ignition spark (stupid young kid then) and was working on something on the engine. Well, the engine killed while I was under the hood, and I was busy for five or ten minutes. When I finally got back to the ignition switch and tried to start it, there was no spark. I finally traced it back to a set of points that were welded together.
When we're working on our trucks, I imagine there are quite a few times that, for one reason or another, we have the ignition switch on and the engine not running. I'm not sure I'd want the full battery voltage running continuously through the coil and points. On the other hand, maybe some brands of points and coils aren't bothered by the extra current.
Tuned
Joined: Jun 2005
Posts: 299
Likes: 2
From: Marryville, Tennessee
I have the Cranecams XR700 E.I. kit on My 55' w/292 seems to run good with it. But My coil gets super hot! I have heard that when the coil gets hot like that that it's bad? I was going to buy a new coil, but will a stock coil do or do I need to get a better coil?? Any help please?
Thanks
Mason
Thanks
Mason
Thread Starter
|
Senior User
Joined: Oct 2005
Posts: 253
Likes: 0
Folow up:
I also looked through the archives and found a wealth if info. It seams that the weakest link becomes the coil with electronic ignition. The weakest link with points are the points being able to handle high voltages without burning up. Some coils are true 12 volt and work fine with a full 12 volts going through it. Some coils are 12 volt that are internally/ externally limited to 6-7 volts. This voltage limiting is what the voltage regulater does. Without the voltage regulator, the coil will get very hot and eventually fail.
The Pertronix info says it is compatable with only 'points style' coils. Six and eight cylinder engines need 1.5 ohm or greater resistance and four cylinder needs minimum 3.0 ohm.
I will be testing the ohms of my coil and leaving the ballast resistor on. Now if I can get up the nerve to go out in the 16 degree weather to change the ignition!
I also looked through the archives and found a wealth if info. It seams that the weakest link becomes the coil with electronic ignition. The weakest link with points are the points being able to handle high voltages without burning up. Some coils are true 12 volt and work fine with a full 12 volts going through it. Some coils are 12 volt that are internally/ externally limited to 6-7 volts. This voltage limiting is what the voltage regulater does. Without the voltage regulator, the coil will get very hot and eventually fail.
The Pertronix info says it is compatable with only 'points style' coils. Six and eight cylinder engines need 1.5 ohm or greater resistance and four cylinder needs minimum 3.0 ohm.
I will be testing the ohms of my coil and leaving the ballast resistor on. Now if I can get up the nerve to go out in the 16 degree weather to change the ignition!
Trending Topics
Elder User
Joined: May 2001
Posts: 736
Likes: 0
From: Owasso Oklahoma USA
Originally Posted by John - NNY
The auto parts place said that it depends on the coil. What is the deal?
BTW it is for a 337 flathead.
John - NNY
48 F-7
BTW it is for a 337 flathead.
John - NNY
48 F-7
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Cargo Master
Joined: Aug 2004
Posts: 2,575
Likes: 36
From: Greenville, SC
I had the same question with my 60 when we converted to Pertronix. I called and discussd this with Pertronix and they said if the original set up had a ballast resistor to leave it in and if it did not there was not reason to add one. He said they have experienced failures of the EI Module when the ballast resistor was removed. The 60 didn't have one, some I am running without.
For what it is worth....
For what it is worth....
Elder User
Joined: May 2001
Posts: 736
Likes: 0
From: Owasso Oklahoma USA
I don't know what year Ford started doing this, but they did have a resistance wire between the ignition switch and the coil to eliminate the ballast resistor. Also for trucks before 1956, they were 6 volt systems that did not use a ballast resistor.
Thread
Thread Starter
Forum
Replies
Last Post
reed1951
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
2
Jan 8, 2012 09:48 AM
John - NNY
1948 - 1956 F1, F100 & Larger F-Series Trucks
1
Mar 27, 2006 06:28 PM