spark plug information

1949ABG

Member
Is there anywhere a guy can look up to see what type of spark plug a certain plug is, and what conditions it runs best under?

Also information somewhere on how to adjust a carb so that all plugs should be equal more or less.

I'm trying to figure out why my "A" runs best on Champion D23 plugs, but my "B" only runs on Autolite 3116 plugs.

Thanks in advance.
 
Try google.
3116 crosses to a D18Y champion. These are a protruding nose lower heat range than the D23
I remember the Y suffix from old champion catalogs I have laying around.

I always used autolite 388 in everything with good luck. I found out here they are a resistor plug. I will keep using them anyhow as they have served me well.

My one tractor 1946 A I use the D23 in it as the cyl. head has a deep counter bore and these are longer and you can get a wrench on them for removal.

Now since these are longer on the outside they just could be interfering with spark plug covers, opening in frame and or type of wire ends letting the spark jump to ground thus making your one tractor not run right with them in it.
 
If either tractor has a Magneto, they are more sensitive to the plugs being NON Resistor plugs such as the 3116 plug. A battery powered coil ignition is less sensitive to resistor versus non resistor plugs while a Mag does better if NON resistor (3116) are used.

The Autolite 386 is a later 18 mm resistor plug close to the original factory heat range while 388 resistor plug is a tad hotter. The 3116 is non resistor in the vicinity of 386 or 388 heat range.

That help??

John T
 
I"ve used Autolite 388"s in a Farmall for along time. Here"s some info on "hotness" from a catalog Autolite sent me a few months ago;

2014 Autolite Spark Plug catalog
Heat Range Chart page 4-5

18MM thread size
1/2” reach
7/8” hex
HOT rating
 388 Standard resistor plug
 3116 ‘Power-Tip’ Non-Resistor plug
 386 Standard resistor plug
• [gap]
• [gap]
 373 Standard Non-Resistor plug
COLD rating

Each step up equals a 70º – 120º increase in spark plug tip temperature.
Self-cleaning zone is 500°C to 850°C tip temperature.
IF TOO HOT = Possible severe engine damage, pre-ignition, detonation with
racing / high performance engines. .
IF TOO COLD = Possible fouling, possible mis-firing, but no engine damage.
 
I have had troubles before with spark jumping to spark plug covers. Run it at night and you may see something new ?
 
Used to be lots of that type information in the Champion spark plug books.

Told of heat ranges & their numbering systems. Cross references between brands & recommended heat ranges based on use of the machine.

Example.... the styled (with maybe a few exceptions) A, B, D, G & H used 18MM non resistor plugs. That "style" was coded by Champion as the D series. The number indicated the heat range. The D16 was only recommended for use in these tractors if used for heavy service. Normal service recommends the D21 and light service the D23.

Back 40 & 50 years ago we all used these tractors for real work and gasoline was a bit different then too. We never had any troubles with D16's but TODAY.... The D16 is as Champion says simply too cold a plug unless used for heavy service! My guess is the term "heavy service" is Champion's polite term for saying "working the snot outta the beast"!

I use D21's & some D23's & don't have trouble.
 

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