Hello all,

Getting ready to do a tune-up on my '86 560SEL w/ 178,000 miles on it – Bosch rotor & cap, Bremi/Karlyn/STI 113M wires, NGK BP5ES (7832) plugs with a .042 gap and some nickle anti-seize.

The plugs worry me a bit as of the eight I have on hand four are the newer “silver” ones made in Japan ones and four are NOS “gold” ones assembled in the US so my concern is whether or not the two are compatible enough to be mixed and matched?

I personally can't see a reason why they wouldn't be which is what worries me :^)

Thanks in advance for your input.

Cheers!

i'd be worried my cylinders be mismatched power wise.I run all copper plugs from Denso with 3 ground straps

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

If they have the same part number then they are the same heat range, same resistance (none) and the same shape, thread pitch, insertion depth, etc.
Your engine would never know. For that matter, you could mix them up with Boschs, Berus, Densos, or any other plug with the same heat range, resistance, tip extension, thread depth, etc; and your engine would never know or care.

Kinda like mixing 3 quarts of Pennzoil and 3 quarts of Valvoline in the crankcase - no harm no foul.

DG

Thank you gentlemen for your thoughts – they are greatly appreciated.


I suppose what was of concern to me was any possible impact that the very different finishes (Ni vs. ??) between the newer and the older BP5ES plugs might have on conductivity, temp, etc. and would it really be enough of a difference to matter.


Given that they are not the easiest plugs to come by around here - combined with my frugal streak - I think I'll mix them - alternating by firing order - and see how that works out for me when I do my tune-up this weekend.


I agree that they should be 100% compatible/functionally identical (famous last words) in theory but am now curious to see how it all plays out in practice.


Cheers!

The finish really should not matter. As stated before, as long as they are all the same heat range and resistance, you will have even power in all cylinders. The end of them all turns brown in the cylinder anyway

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Dockside: 1968 Eltro 17
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