I have searched here and google and I found to use BTF-31 Autolites but I believe they are discontinued or out of stock everywhere. I know champion has a cross number but I dont like champions. So I was hoping somebody would know what is another Autolite plug that will work for my stock i6 300. All I can find is autolite 45's

 

how are autolite 124's?

Autolites site says they are btf-31 replacements

 

I call and ask Autolite and they say I can use either an Autolite 45 or the 124 in my 300 i6, but they dont have gapped specs for points ignition or electronic.

My question is, since the 124's are the OEM replacements of the factory BTF-31's, will I have any troubles running the 124's? I know the 124 is only 1 step colder than the 45 autolite but in my searching people say to use the 124 in race engines or high reving applications. I dont understand why that would be if the 124 is the factory replacement plug. Also what would be the proper gapping for my i6? Both for points and electronic ign if you guys know it....

Surely someone knows fellas

 

Nobody here runs spark plugs in their trucks?

While replacing mine to some 124's the wires broke so I had to replace those.

Wired everything back up correctly in the right firing order and now the truck doesnt even try to start. Everything worked perfectly fine before with the 46 plugs and now nothing.

 

What is the I-6 installed in, an F500 or larger series truck?

Be aware that 240/300's not installed in 500 and larger series trucks used the same plugs as 289/302/352/360/390: BF-42 or BRF-42

If you had the '64/72 Ford truck parts catalog, you woulda found this out. Or, if you asked someone who passed out Ford parts to mechanics for 35 years, he woulda...and is now telling you the same thing.

BTF-31 is a H/D plug, colder (the higher the number, the hotter the plug) than BF/BRF42's. Were usually installed in 500 and larger series trucks with 240's, 300 H/D's & FT engines.
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FoMoCo was forced by the US Gov't to sell Auto-Lite in 1972 because the gov't claimed FoMoCo had a monopoly on autoparts. FoMoCo then started in-house brand Motorcraft,

The Auto-Lite part numbers then became Motorcraft part numbers.

If you really want BTF-31 .. I dunno if the following are Auto-Lite or Motorcraft:

HAVEN FORD in Haven KS has 24 = 620-465-2252.

GREEN SALES CO. in Cincinnati OH has 195 = 800-543-4959.

Haven will probably be cheaper.
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Parts catalog sez: BTF-31 .. 18mm -13/16" hex head taper seat / gap setting .028 / .032

BF-42 .. 18mm -13/16: hex head taper seat / gap setting .032 / .036

BRF: R = Radio resistant, otherwise same as BF-42

And, if your truck is an oil burner, you'll want a hotter plug: BF-82 or BRF-82 / Same gap as BF-42

 

It is an f100 and my motorcraft parts catalog calls for the same plug in the f100. Its a book dated from the 80s. Autolite also has the btf-31 equivelant which is the 124. I just put those in today along with new plug wires and now I have a sputter while accelerating. At idle it revs fine but while driving it sputters. The previous owner had champion plugs that were 2 stages hotter than these 124s.

Do you think I need to make carb adjustments? I have no vacuum leaks and no miss from the ignition side of things. I checked each plug and it fires fine. The previous owner also put in a new carb but it ran just fine with the champions.

 

Let me rephrase that, in drive while accelerating it sputters and in park and to rev it up it don't skip a beat.

I am thinking to lean? I also have a set of autolite 45's I will put in tomorrow. The autolite 45 is direct cross part# to BF-42

 

Pull the plugs and read them for color as a whitish color=lean to hot of plug. A carbon fouled= rich~~ to cold ...Remeber to set point first, then set timimng...
orich

 

Got an update:

I replaced the autolite 124s that my 1982 motorcraft service book called for with some autolite 45s gapped to .035 and without doing any carb adjustments they were already better than the 124s and the champions that were in it. Quicker starts smoother idle and cruising speed. I went over to my friends shop and we set the timing to 10* btdc because of the altitude, we leaned out the carb some when we were tinkering and it took 5 full turns before anything happened. So it was way rich and that would explain the gassy smell.

Took it for a test drive and it had much better throttle response and idle speed. I am satisfied with it now. It looks like the 124s are far too cold for my truck and the 45s were perfect. I have a pertronix electronic ignition on the way along with some wheel vintique chrome 15 x 8 smoothies and a smittys glasspack.

 

I was also told to re-gap my plugs to .044 when I switch to electronic ignition.

Why is a bigger gap needed? Is it due to the higher input voltage?

 

With a little hotter spark you can open the plug gap it lengthens the spark for a better burn and starting up the motor.. You can run a full 12 volts. If you use the first generation unit make sure you never leave you ign key on over one minute or you'll over heat and cook unit and you''ll need a tow truck to get your truck home..2Th & 3rd generation units have a built in trip switch so it won't over heat & cook them. II & III generation units are way better as a improvement..
Just a heads up..
orich

 

What exactly are you refering to when you say "unit"?

There was only one pertronix model that will work with stock coils available for my distributor

 

AW i'm thinking you'll be going with the Pertronix dizzy unit assume??
orich

 

Yes the 1261 conversion deal. Found one for $45