new pertronics ign and flame thrower coil, what plug gap?

the flame thrower advertises that you can enlarge the plug gap to get better gas and more power but it doesn't give a suggested plug gap? anyone have any experiences with this? Thanks
 
A coil builds voltage to the point where the spark jumps the gap. Make the gap as wide as possible.
 
I never personally like the electronic ignition. I installed a couple of them on my tractors and a month or so after the warranty expired both of them died. I went back to points and condensers. I could not see any difference in performance with the electronic ignition. However, I do like the flame thrower coil. I open my spark plug gap between 0.007" to 0.010" bigger than what is called out in the manual.
 

Depends on the compression ratio, combustion chamber design, ignition coil, distributed cap spacing between terminals, resistor or non resistor wires or plugs and moisture.
 
What tractor are we talking about here? I have several 2 cylinders so equipped, the longest since 2001. I keep plugs set at .030. With electronic, I spend a lot less time and money on plugs, points, etc. It's been good.
 
Too many variables to give any exact answer. Your new elec system has the capacity to achieve higher firing voltages which means it can fire a wider plug gap, however as voltage increases, the voltage withstand rating on your stock distributor cap, rotor, and plug wires comes into play IE if you widen the plugs too much you could get plug wire failure (so use good quality plug wires) or dist cap or rotor HV breakdown...........

That being said and based on experience and antecdotal evidence, Id say run a gap from at least 0.035 up to 0.045 or so and keep a close eye on the cap and rotor for arcing or carbon traces, but they will likely be fine if you have good cap and rotor and plug wires at those gaps. Ive seen 0.050 but remember the old tractor system and its cap and rotor is NOT the quality of a late auto where they may run wider gaps.

John T
 

1965 John Deere 2010
1952 John Deere A
1950 John Deere MT

All of the electronic ignitions burned out shortly after the warranty expired. I have ten 2 bangers, some with mags and most with distributor. I have no issue with the points and condenser. I was convinced by several people that the electronic ignitions was the way to go.

If you have a good coil, wires, and plugs I can not see what you are going to gain with the electronic ignition. These tractors ran for 50 - 60 years with points and condensers, why switch now?

I do like the flame thrower coils, I think there are worth every penny they sell for. It makes a better spark and you can increase the gap, I like to increase the gap to 0.007" to 0.010" bigger than what's recommended. I also like to run one spark plug hotter than what is recommend, this is to help keep them clean with using the Unleaded gasoline
 
Nothing wrong with the gap you have. I keep reading wider and hotter is better but there is never an explanation of how it helps anything. The only thing the plug does is ignite the fuel/air mixture.

The gap changes nothing. There would be no difference in stating a stick of dynamite will have more power if you double the cap size. That cap is just like a spark plug, it ignites and nothing else. If a bigger spark is all it takes to make a bigger boom when no other variables are changed someone needs to explain how it's possible. JMO
 
(quoted from post at 06:17:00 07/17/15) the flame thrower advertises that you can enlarge the plug gap to get better gas and more power but it doesn't give a suggested plug gap? anyone have any experiences with this? Thanks
My 51A with 7.45:1 compression, Champion 16 plugs .035 gap & 50A with 10.5:1 compression, NGK 5724-8 plugs .035 gap, no problems so far. Either one will usually start by the 2nd revolution.
 
(quoted from post at 17:17:56 07/17/15) Nothing wrong with the gap you have. I keep reading wider and hotter is better but there is never an explanation of how it helps anything. The only thing the plug does is ignite the fuel/air mixture.

The gap changes nothing. There would be no difference in stating a stick of dynamite will have more power if you double the cap size. That cap is just like a spark plug, it ignites and nothing else. If a bigger spark is all it takes to make a bigger boom when no other variables are changed someone needs to explain how it's possible. JMO

I'll take a stab at it not being able to back it with any evidence just my 0.2 cent commen sense. I would think in theory the coil being hotter would allow the spark plug to have a greater gap with higher intensity(more volts=bigger boom for ignition) therefore creating a faster and more evenly burned air/fuel mix which would in turn create more hp and better fuel efficiency due to a cleaner burn in a shorter amount of time. It makes sense in my head but I'm a numbers man so it would have to be proved with evidence from tests.

I would find it hard to believe you could actually notice the hp increase or fuel efficiency though. That is what the manufacturer of the product claims. My guess is only a standard test in a controlled environment would do so. To many variables otherwise to say it does or doesn't. The test may have been done.

Little off topic just but just trying to have conversation with M-MAN since the subject was brought up.

My answer to your question would repeat what others have stated with the gap being between 0.035 and 0.040.

OldCrow
 
have installed 5 of these units and I really don't think gap matters....leave at factory setting....type of plugs I used never mattered either....
 
To add to John's good information, I have two tractors with electronic ignition. One is a 60 that I used to pull with "higher than stock" compression. I use 3116 plugs with about .040" gap. The other tractor is my 70 puller. It has a 14mm automotive plugs in it and I run upwards of .050" gap on it. The ignition system is powered by an MSD box. Both tractors have a stock distributor cap but the 70 has larger wires. I have not had a problem with either tractor. John's estimate of .035-.045 gap is pretty good, assuming the tractor does not have exotic compression. The more compression you have, the better spark you need. I have had nothing but good luck with the Pertronix products and would not hesitate to use them again. As hard as it is to get good quality stock ignition parts anymore the electronic ignition is looking better and better, in my humble opinion. Mike
 
Hey M Man, I agree that unless you have extreme high compression if you have a stock or elec ignition isn't gonna change the HP much if any at all. As far as the initial fuel air ignition process is concerned, if you have a higher energy ignition (Arc has More Volts x Amps x Time) across a wider plug gap, that's more energy being expended across the pug gap when it fires with an arc of more length (wider gap) which is also an arc with more surface area. I see that as straight physics and engineering, a higher energy ignition when it fires produces more amps x volts x time and the wider plug gap means the arc has more surface area.

HOWEVER I cant say that ignites the compressed fuel air mixture any better or faster then a shorter lower energy arc ????? I just don't know the deep physics behind the initial explosion and if a higher energy arc ignites it better or no difference????

Oh well,

John T
 
Hey John T - you describe the physics of the situation very nicely! Now let me add a couple comments:

A longer, hotter (ie. higher energy) spark does nothing toward increasing HP under load. All the spark does - any size spark - is INITIATE the burning process in the cylinder.

The one case where spark energy/size matters is when a gasoline engine - especially a carbureted engine - is cold or idling with no load. In these situations the much of the fuel enters the cylinder as liquid droplets. Consdquently the fuel and air are not well mixed. Now a short, low energy spark occurring in an excessively lean or rich region of the F/A mixture will not ignite it. This results is a misfire and unburned fuel going out the exhaust.

This is one reason car manufacturers went to HEI and longer gap plugs in the 70's - to reduce emissions.

...Bob M, the retired mechanical engineer
 
Makes good sense Bob, that explains why so many who install elec ignition report much improved cold weather starts and better idling.....

John T
 
when in high school hei ignitions had just started to be used on new cars, auto mechanics teacher said that the hei systems used 60,000 volts compared to around 40,000 volts conventional ignition system plug gaps when from .035 to around.060,hence it's easier to start a fire with a blowtorch than a match
 
The main advantage of electronic ignition was the elimination of point bounce
at high racing rpms.
That being said, I have two 4020 loader tractors that are used around the shop.
One is electronic the other an LP now run on gasoline. Both have plugs set on .045.
Horsepower is of no concern to me.
The engines mostly idle, are worn and plugs do run longer before fowling out
than at lesser gaps.
I don't install sets anymore, only individual plugs as needed (usually the same cylinders).
No more problem with caps, rotors, etc with electronic tractor than points tractor.
Does eliminates point, condenser etc maintenance. Have had the electronic ign. for many years.
 
John T;
Fun chat! I thought it was interesting that D reported longer time elapsed between plug fouling with a wider gap. I wonder if the wider gap leads to cooler plug arc points?

Bob's comment on a poor combustion mixture sounds valid. A wider gap as a Band Aid for an improper fuel mixture? Our old friend Glen would like that. LOL
 
(quoted from post at 13:28:22 07/19/15) John T;
Fun chat! I thought it was interesting that D reported longer time elapsed between plug fouling with a wider gap. I wonder if the wider gap leads to cooler plug arc points?

Bob's comment on a poor combustion mixture sounds valid. A wider gap as a Band Aid for an improper fuel mixture? Our old friend Glen would like that. LOL

If you really want to brag about spark. Convert the tractor to 12V negative chassis. Obtain the 12V neg Pertronix II for a Delco distributer and a 0.5ohm primary coil. Obtain a GM lost spark coil pack . Forget about using the distributer except to provide advance and a place for the Pertronix. Run spiral wound ignition wires from the coil posts to the spark plugs, position doesn't matter.
This system would probably still fire the gaps if you broke the ground electrodes off the plugs.
 

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