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Found this thread with pictures, post #11: http://www.ranger-forums.com/4-0l-ohv-sohc-v6-tech-33/can-u-use-single-platinum-spark-plug-4-0-sohc-119625/
Thank you to Takeda(Bob) for taking the time to photograph and post these pics
These pictures are worth 2,000 words, lol.
What got me looking was a comment about Ford factory installing 2 different spark plug types on the same V6 engine???
Cylinders 1, 2, 3 got one type
Cylinders 4, 5, 6 got another type
Waste Spark runs 2 spark plugs in series, + to - and - to +
So spark goes from electrode to tip on one plug and tip to electrode on the other.
Ford installed platinum tip on one bank and platinum electrode on the other, when buying thousands of spark plugs saving a few cents per plug adds up.
Coil wiring:
3 4
2 6
1 5
Front
Point being when replacing spark plugs on a waste spark system, use double platinum if you want them to last.
Platinum tip will last but only on one bank, platinum electrode will last but only on the other bank, lol.
Unless you want to buy two sets of 3 spark plugs just get double platinum.
While this was 4.0l related I would think it applies to all waste spark engines
My 4.0ls would eat non-motorcraft plugs but it did seem even the motorcraft didn't last as long as I would expect.
I now think it was the waste spark system, not the 4.0l, and my choice of spark plugs, never did get double platinum, I will now
Thank you to Takeda(Bob) for taking the time to photograph and post these pics
These pictures are worth 2,000 words, lol.
What got me looking was a comment about Ford factory installing 2 different spark plug types on the same V6 engine???
Cylinders 1, 2, 3 got one type
Cylinders 4, 5, 6 got another type
Waste Spark runs 2 spark plugs in series, + to - and - to +
So spark goes from electrode to tip on one plug and tip to electrode on the other.
Ford installed platinum tip on one bank and platinum electrode on the other, when buying thousands of spark plugs saving a few cents per plug adds up.
Coil wiring:
3 4
2 6
1 5
Front
Point being when replacing spark plugs on a waste spark system, use double platinum if you want them to last.
Platinum tip will last but only on one bank, platinum electrode will last but only on the other bank, lol.
Unless you want to buy two sets of 3 spark plugs just get double platinum.
While this was 4.0l related I would think it applies to all waste spark engines
My 4.0ls would eat non-motorcraft plugs but it did seem even the motorcraft didn't last as long as I would expect.
I now think it was the waste spark system, not the 4.0l, and my choice of spark plugs, never did get double platinum, I will now
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