Has anyone here ran the Bosch Platinum 4 spark plugs in anything? How do you like them? Are they worth the money? I am thinking about putting a set in my 94 Aerostar. I have always ran the regular Bosch Platinum plugs and had good luck with them. Thanks.

 

Not personally but a fellow I know with a Saleen Mustang, a Nissan Maxima, and Honda Civic CRX-SI uses them in all three and says they work great.
It's hard to tell if they are a marketing gimmick or a real inprovement over the old Plantinum plus plugs.

When I changed out the original Motorcraft plugs for new Motorcraft plugs in my 88 Aerostar 3.0L, they still looked nearly new at 30K miles. There was no perceptible change in performance then or now 28K miles later and I've come to the conclusion that the 3.0L, anyway, is very easy on plugs. I'm planning to run them until I think they are beginning to show signs of performance and mileage deterioration since it's a bit of a pain changing them which you know if you've ever done it. I'm suspicious that Ford's recommendation to change plugs at 30K miles is very conservative and is more to help make their dealers make money then provide any real performance/mileage gain. Just my opinion having changed plugs for many years on cars and trucks.

Mark

 

Platinum is more chemically stable than copper but has a higher electrical resistance and lower heat conductivity than copper. I've never read any articles which attempt to explain the reasons for older engines going through plugs every 12-20k miles but they certainly did. I suspect that the lead, along with richer mixtures, less sophisticated oil control etc. caused more galvanic action in the electrodes which erroded them away faster but not sure about that. There are some simple rules about plugs though:

Due to the higher electrical resistance of the platinum plugs you should not use them with older ignition systems. If you upgrade to an MSD-6 or something along those lines then they would work well but may actually reduce performance in older engines with stock ignitions. (pre second generation dura spark)

Their primary advantage is longer wearing electrodes. Since the spark is what does the work not the material they are made of, the engine doesn't care a hoot about platinum or copper but the better chemical and mechanical characteristics of platinum will make them much more durable in the combustion chamber than copper so they last longer. I would venture to say that without platunum plugs the 100k tune up in new cars could not be acheived but there is no performance gain inherent in the material itself.

Lean burn engines (late model Aerostars) require larger gaps due to lower molecule density of fuel in the air mixture to allow more molecules within the range of the spark for better ignition so it follows that the more spark area there is the more reliable the ignition will be as well. 4 electrodes allow for at least one (the one with least resistance) to fire every time and several others will also fire if the spark intensity of the ignition system is sufficient to carry the current so again, the better the ignition system the more likely you will see "any" benifit from these plugs and again, on older ignition systems or engines which are burning some oil they will probably load up more easily than the single electrode copper or platinum plugs.

If you think you have good performance now with platinum plugs....try properly gapped, single electrode copper, non resistor plugs (if you can find them :-)) with hellical MotorSport 9mm wires.....then let's talk plugs :-) Plug life is another matter altogether :-)