Author Topic: sparkplug internal resistance  (Read 1369 times)

rosch

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sparkplug internal resistance
« on: June 23, 2024, 08:03:28 »
General concensus is to use NON-resistor sparkplugs ie NGK BP5es in our SL's iso (supression) resistor plugs like NGK BPR 5es.
However when I use an Ohmmeter and measure the internal resistance of my brand new non-resistor BP5es my measurement varies between just a couple of Ohms to a few hundred Ohms . Quite a spread . Is this normal ?
My idea is it should be somewhere close to 0 Ohms.
Hope somebody will shed a light on this.

BobH

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Re: sparkplug internal resistance
« Reply #1 on: June 24, 2024, 11:43:51 »
Hello, from what i understand, non resistor plugs have an internal resistance of between 1K and 2K ohms, depending on the make and type.  Resistor plugs can be 4K or well over, a massive difference.  Add to that the resistance of the plug wires and you can see why fitting the correct plugs and wires is important for correct running
February 1965 230SL Automatic
UK delivered RHD
Papyrus white, blue hard top & hub caps
Blue soft top
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mauro12

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Re: sparkplug internal resistance
« Reply #2 on: June 24, 2024, 15:00:37 »
Is it true that Bp5es ngk are starting to be difficult to find ?
Mauro Pisani
250sl 1967 5speed zf manual

rosch

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Re: sparkplug internal resistance
« Reply #3 on: June 24, 2024, 19:09:28 »
@mauro 12,

Still no problem to obtain NGK BP5ES non-resistor. You might find them by searching  for NGK article number 6511 or
EAN: 0087295165119