bass

Member
hay y'all I need to replace the wire inside my mag that goes from the points to the condenser. what gauge wire do i need to use?

bass
 
18 AWG automotive wire should be fine. What is most important is the rated insulation on it. should be 60v or better, and rated at least 70 degrees C.
 
The wire from points to condenser carries very low current, but you still want big enough wire to have some degree of mechanical strength so I might use 16 or 18 gauge no less then 20. When the points break open there's a voltage rise/spike of wayyyyyyyyyyyyyyyyyyy higher then 6 or 12 volts, so Id want wire with an insulation and voltage withstand rating of at least a few hundred volts, I forget what the typical voltage rise is, sorry, but for sure you don't want low voltage wire. Usually the condenser pigtail wire is long enough to reach points??

John T
 
John, I agree 100%. What I posted was typical automotive wire ratings. You can certainly get 18 AWG rated at 600v, but not at your local auto store. I would think (which is dangerous when I do it) that a 60v rate wire insulation would be higher resistance than the spark plug gap, but it would be an interesting test.......
 
Tom, good info, a 0.030 spark plug gap takes something like 10,000 volts (subject to fuel and compression) potential difference in the combustion chamber before current arc jumps across it, that and the rest of the plug assembly has an extremely high voltage withstand rating or else current would arc somewhere OTHER THEN the plug gap. My best pure "guess" is the voltage across the points when they break open may rise to lets say 100 to 300 volts, but that's obviously nowhere near the 10,000 volts across the plugs gap??? If I had to buy wire for the condensor and had to chose between only 50 volts versus 600, Id opt for the 600 volt rated wire myself.

Fun sparky chattin with you, take care

John T
 
yup John, sparky chat is good fun. The original poster might be able to find 18 AWG THHN at Lowes or Home Depot, being that THHN is rated at 600v and 90 degrees C.

So, if you consider the primary windings VS. the secondary windings in the coil, we know there would be a significant voltage difference between the 2. You and I also know that when the magnetic field collapses, those pixies are going somewhere. My belief is that if you look at the resistance per volt for the auto wire insulation on the primary vs the resistance per volt on the secondary for the plug gap, I think the plug gap will "release the pixies" before the insulation on the auto wire does. Plus, you have the "tanker truck" of electricity (the condenser) on the primary side, so my bet is on the plug.

Another aspect of this whole question would be the "charge time" lag on the condenser vs. the lag time for the ionization of the fuel/air mixture on the plug side. Kind of like the solid state 3 Phase converters. When you first turn it on, there is a short delay while the DC capacitors charge up to feed the switching gate before you start getting your 3 phase power. For the magneto or battery ignition, I would liken it to a "race to the finish" for the pixies. While the capacitor is charging, the ionization in the plug gap is starting. Once that resistance "dam" breaks open, all the pixies are going down that path.

However, I could be 100% full of it too. Good stuff. :wink:
 
It would take a scope and be interesting to view the HV rising over on the Secondary and the LV rising spike across the points (regarding the condenser wire insulation rating) when they open all simultaneously in real time to see just what happens and when. Of course, he needs good fine stranded wire with flexibility leading to the condenser which solid THHN etc wouldn't have.

Its getting deep here, were probably boring the others but were havin fun lol

John T
 
Wish I had a scope, as I would wire a mag up and see what the outcome was. If you have one, go for it, and post a vid of the result. I subscribe to a guy on YouTube that might "eat this up" as a video post. I'll ping him and see if he bites.

Here is what Lowes shows for 18 AWG.

http://www.lowes.com/pd/Gardner-Bender-35-ft-18-AWG-Stranded-Copper-Wire-By-the-Roll/3376902

THHN comes both solid and stranded. Lowe's just doesn't seem to carry the bulk 18 AWG in either.......just what is listed in the link. The specs on it would certainly fit the bill.........but wowzers, 35' would do 1000 mags! (I think)

:shock:
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top