Recently I was experiencing a long crank time to start and rich exhaust fumes on my Mercedes-Benz 560 SEL. Upon removing the spark plugs I found that the gaps had opened up to almost .070 Gap! I like to test different plugs and I had elected to try an NGK plug and overall they did well for a little while but I'm not happy with the wear on these plugs.
Usually it's just best to stick with the OE Mercedes 003 159 10 03 spark plug, but from time to time, depending on stock and availability you can find yourself forced to seek out a suitable replacement. I found myself in this situation recently and am happy to report that Champion makes a resistor less spark plug PN# 302 or n11yc.
The Champion plug had some weight to it, more so than the worn NGK BPR53S. I was also quite impressed with the near night and day crank to start time that was virtually instant when installed. Also gone was the rich exhaust smell that had developed.
Just wanted to report the findings. It's important to tune up your Mercedes with new spark plugs every 15,000 miles! The cap and rotors are usually good for 60,000 and the wires are know to last well beyond 100,000 miles providing they do not get oil saturated. Gap should be set at .032 - .035
Anyway, here's to a fresh tune on your Mercedes!
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What is to give light must endure burning -- Viktor Frankl
Good post, & thanks for the insight. Yes, ever since Bosch modified their plug-line-up, it's been difficult to determine the best plugs to fit. I have to admit right here, that for me having been once upon a time used to paying about $02:00 per plug, I look around now for the best deal, since a MB dealership will now sell them to me for around the $12:00 mark each-plug, with $08:00 per plug the average price to be paid elsewhere, brand depending...Yes once upon a time I could buy a box-of-10-plugs made by Bosch of W7,-8,-9DC's for under $20:00....
Anyhow, my Suzuki motorcycles have always successfully used NGK plugs ( I don't think there are any alternatives LOL ), & I've since sourced some NGK plugs for my little 350 V-8. BP6ES is the code name, & I'll let you know how they go...They've always been dependable on the motorcycles, that's for sure, though I must admit to seeing the gaps open-up too, with the center electrode wearing down to nearly the same height as the plugs outer-rim. ( Nearly to the porcelain insulator ). At near $04:50 per plug paid for NGK, you can see why I'll be happy with thee LOL ! I change them & the ignition point once a year, so the rest doesn't matter, regardless of mileage. ( Would you believe that ignition-points that were once less than $10:00 now cost well over $50:00 !).
Cheers,
Rastus
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"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
I guess we shouldn't be real surprised when it comes to the wear characteristics of "copper"'plugs. It's really quite a normal process given the softness. Still, it just seems like the NGK's wore quickly -- however that's not to say they didn't perform well leading up to the point they became excessively worn. As I have said many times before -- these cars will run with resistor plugs and not much if any loss of power can be felt.
Of course that doesn't mean that folks shouldn't try to get the factory "non-resistor" plugs as these cars left the factory with -- just that if they ever find themselves in a pinch, resistor plugs will still net much better results than excessively worn or fouled non-resistor plugs.
Now days with the new cars using platinum and iridium "fine wire" plugs it's totally common to see a set of plugs last way past 100,000 miles with as little as .005 wear! I see it all the time and I'm always amazed. Then again these newer cars usually have digital ignitions without traditional cap and rotor "arc" style ignitions. Back in the day when I was running nitrous in my Mustangs it was common to see the entire electrode melt away after several hard 1/4 mile passes. Back then I used a Champion truck plug with beefy electrodes to prevent this.
The Champion plugs I mention for the 560 Mercedes (Stock #302) are relatively inexpensive @ $2.10 a plug.
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What is to give light must endure burning -- Viktor Frankl
