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Before I installed the EFI system and the EDIS ignition system I was running Motorcraft ASF42C spark plugs in my Pantera.
Now I tried with NGK BPR6FS but some of the spark plugs were damaged because of running too lean. I had the wrong type of fuel filter installed so the fuel pressure dropped on acceleration.
Then I tried to change back to the MotorCraft spark plugs again and the motor is running fine. I don't think the Motorcraft spark plugs I have is the best choice for using with EDIS system. The recommendation for EDIS is with double platinum spark plugs.
Anyone that can point me in the right direction?
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I can only tell you the temperature range of the plug that you need.
I am not familiar with the plugs that you are mentioning. They sound like they use a gasket on them like for the aluminum heads.

The temperature range that you need for any Ford High-Performance engine on the street is going to be the original Autolite AF32 for the original iron head 4v Cleveland or a BF32 for the 302-351w heads.

These are tappered seat plugs. The AF is a 14mm and the BF is the 18mm.

Around 1968 Ford sold the Autolite Division and created the Motorcraft Division.

The plugs became Motorcraft AF32 and BF32.

Recently Motorcraft stopped producing the BF32 as such and substituted the BF42 for it. This is a hotter plug and will generally cause some detonation in the cylinder over 5000 rpm. Do not use it.

This substitution by Motorcraft caused a domino effect justifying other companies to cross reference thier equal to the BF42 as the same as the BF32.

It is not so. This is a typical Techno-geek, pencil-neck, no practical knowledge anal retetive, screw you procedure.

You want the equivelent of the ORIGINAL 32 heat range. Crossing that over to another brand has now become a pretty large problem.

Do not use the Autolite 45. It is not the BF32 as it statee. It is the BF42.

Your best bet is to go to a Champion plug. They have the greatest variety and still have most of them available.
From what I am reading at the Sumit Racing page, the heat range needs to be specified.
I would NOT trust a salesperson to specify the heat range BECAUSE of the error in the listings.

I think that a hotter plug is going to make a lean condition worse. Maybe put a hole in a piston, maybe warp the valve seats.

A 42 heat range is pretty hot. Even under normal conditions it will show a chalk white electrode.

The electrode should have a medium grey-brown color to it and the tip should be clear, no deposits.

A double platinum is made for 100,000 miles. It is intended originally for hard to change plugs. You don't really need them in a Pantera but they won't hurt you either.

I forgot the 14mm part numer but the 18mm is an F9y champion. I know you can get it in a double platinum.

The temp range of that plug is right on it. With the Motorcraft solid state ignition the tips will just stay clear with about a .038" gap.

Ford actually recommended a .042" gap back in the '70s for similar applications but that can lead to premature coil failures.

That's what my 302 '75 Granada used.

.037-.038 is about right for your application. They will probably be .032-.035" out of the box.
Even .035" is ok.

I presume that you have been trying to cross reference over to another plug brand. I am explaining all of this to you because I just went through this with My 68Shelby and the unavailabilaty of the BF32's.

That's how I found the mistake in the listings.

Many if not most of the cross over charts are just plain wrong. The were caused by Motorcraft substituting the 42 for the 32 and stating that they are equal. They are not. That is simply not true.

If they were the same they would have the same number. Any tech who insists they are should at least be sterilized so that they cannot reproduce more little assholes.

The ONLY two brands that I know are right are the Motorcraft and the Champion. I did not try the Bosch or the NGK. They were not "stock" items locally and needed to be ordered.

I will not order something if I don't know for sure that they are right.

I should point out that Accell and Splitfire may have plugs that you can use. In the past Splitfire has offered triple platinum.

SF2D is the regular plug number and TP2D the triple platinum, Splitfire plugs.
Last edited by panteradoug

platinum plugs are installed by the OEM's in order to extend service life. The ignition does not care what material the spark plug electrodes are made of. In the US auto manufacturers are required by the federal government to warrantee the emissions systems for 100,000 miles. This has forced them to design spark plugs that will maintain optimum performance for 100,000 miles. This has resulted in the use of very small "pointed" platinum electrodes. The new Bosch "surface gap" style spark plugs with either 2 or 4 side electrodes looks like a good design as it completely "unshrowds" the spark.

cowboy from hell
Last edited by George P
So a champion spark plug with heat range 9 is good. I found RV9YC by champion, it's for marine application and so was the NGK BPR6FS I used before. I have no idea what the difference are for marine application.
OK I understand now that I don't need double platinum spark plugs. The more I Google the net the more confused I'm. You are absolutely right about all the cross over charts.
If you look at the Bosch plugs that Ron just posted, you can see how some of the plugs ranges, you could use a 9 or a 10.

This is a good example of how the heat ranges from one manufacturer to another are not the same.

The Bosch is showing an 8 heat range in the area that you are looking for.

I would guess and say that even though the Bosch is applicable, and probably will run just fine for you, it probably isn't designed specifically for your application.

The Motorcraft and the Champion are.

I think that all of the manufacturers web sites explain what the prefixes and suffixes indicate in the part number.

Some mean that it is a copper core, C. Some indicate that it is an extended tip, etc.

Champions are not my favorite plug by any means.
The AC, the Autolite, and the Motorcraft are by far a better plug in the standard configuration.

In my case I had no choice. Like they say. It was the only game in town.

Also, any racer will tell you that you need to experiment with the plugs anyway.

I know that when I was racing either the AF22 or the AF32, depending on the track, the air temp, etc could have been correct.

The AF22 is not what you drive on the street. It will foul quicker then sh.. goes through a goose.

Incidentally I still have a new set of AF901's here. That plug will foul up under 3,000 rpm's so it is strictly for "Bonzai!" type racing.
You can't even use those on the dragstrip. You will never even get to the starting line.

You have to have the car already hot from another plug and then switch it over to the 901's before it cools down. Try that one for fun!
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