I put Bosch platinum plugs in my 1 ton - 454 Chevy truck last year.
As you mentioned the new spark plugs didn't seem help a whole lot as I am
accustomed to with new plugs. Misfires did not decrease. Do the Bosch plugs
have a higher value resister built in? Where is the increased resistance
coming from? The plugs I bought were being clearanced at some autoparts
store in Kentucky so at least I didn't pay a fortune for them.
Dave
>>>>>>>>>>>>>>>>>>>>
Carol Kenyon wrote:
> Here I go again, ranting... I work on cars and
> light trucks for a living. I realized yesterday as
> I was removing yet ANOTHER set of Bosch Platinum sparkplugs from a
> customer's car that
> good people on this list mght have fallen into this trap.
> In my part of the world the DIY auto parts
> stores push these pieces of junk. They are completely unacceptable for
> most U.S. cars
> and just about ANY older vehicle I can think of.
> If you have a BMW, Volvo, Mercedes-Benz, maybe...
> Here's what's wrong. I call it "running out of
> spark". On the 'scope, a good sparkplug requires 7 to 13kV to fire.
> Most systems will
> max out (12v electronic ignition) at around 30 to
> 35 kV. Older 6v systems will be less, 20kV?
> The difference between firing voltage and maximum output is like a
> reserve. As soon as you put the pedal to the metal that reserve begins
> to narrow. Add a heavy GVW, lean mixture, too wide of plug gap, etc, and
> the reserve is JUST enough to prevent misfire.
> Let's add Bosch Platinum plugs to the mix!
> They require somewhere around 80% of max output AT IDLE! You can see
> that your ignition
> system will "run out of spark" very quickly.
> God forbid you forgot to take the choke off or
> you happen to be running old gasoline! The
> spark will completely bypass this "huge resistor"
> of platinum electrodes and just run down the coated insulator.
> There MUST be someone on this list who has
> had problems with "high performance-long life"
> platinum plugs.
> I'm not just picking on Bosch, "Split fires", and
> other platinum plugs are just as bad.
> I know that certain vehicles REQUIRE platinum plugs. Use what came in
> them originally.
> If I hurt someone's feeling with this, too bad!
> It's the truth!
> Don Kenyon ASE Certified Master Automotive Technician, L-1, CA Enhanced
> Smog License
>
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This archive was generated by hypermail 2b29 : Tue May 01 2001 - 07:42:39 PDT