Whenever I change plugs, I always put Iridiums in. So far, I've never had to change them twice.
Clarification on Upgrading Spark Plugs
- Thread starter Gebo
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IMO the electrode material is not as important as the plug "reach" and the resulting position of the spark gap in the combustion chamber.
Too long a reach can be an obvious problem: hitting the piston, but a non OEM plug with a shorter reach would be fine mechanically,
but performance may be affected because the spark occurs closer to the combustion chamber wall.
Too long a reach can be an obvious problem: hitting the piston, but a non OEM plug with a shorter reach would be fine mechanically,
but performance may be affected because the spark occurs closer to the combustion chamber wall.
Well, let's not end this thread by inserting some doubt about the reach. Just check your Iridium plugs against your OEM's. If you used their cross reference chart correctly the ground electrode will be in exactly the same position as the OEM.
Personally I have not used a "copper core" plug in over 20 years. I use precious metal plugs in everything inc OPE and never had a failure. They stress the coils less and fire easier than coppers because of their reduced firing voltage requirement. Anyone want proof try a precious metal in a lawnmower or other OPE engine that is hard to start.
This is a perfect test engine as it uses a magneto ignition that needs cranking speed to generate enough voltage to fire, the precious metal plug fires right up at a lower cranking speed. I told the OPE dealer this and he called B.S to it but tried it anyway, now he is a believer with and has fewer wont start service calls under warranty.
I had a brand new (still have it 10 years later) lawn mower my wife could never start, she couldn't pull it fast enough, I put a platinum in it and she can start it first pull every time. In the snow blower the results were even better. Keep in mind these are the simplest of engines with no ecm and simple carbs so any difference in performance is easy to see.
This is a perfect test engine as it uses a magneto ignition that needs cranking speed to generate enough voltage to fire, the precious metal plug fires right up at a lower cranking speed. I told the OPE dealer this and he called B.S to it but tried it anyway, now he is a believer with and has fewer wont start service calls under warranty.
I had a brand new (still have it 10 years later) lawn mower my wife could never start, she couldn't pull it fast enough, I put a platinum in it and she can start it first pull every time. In the snow blower the results were even better. Keep in mind these are the simplest of engines with no ecm and simple carbs so any difference in performance is easy to see.
If you are upgrading or replacing plugs in an engine with a "waste spark" ignition system you want plugs that are double iridium or double platinum to take full advantage of the exotic metals imbedded in the plug electrodes. The spark, or electron flow, travels from the center electrode to the side electrode on half the plugs and the opposite direction for the other plugs.
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