kimman

Hey guys,

I'd like to do the annual maintenance due to service B alert within next 600km, i perfer to change to spark plug at the same time that can give better performance, do anyone can give me detail of upgrade spark plug for me?? Which brand, material or part number??


Thanks at all!!

Adolph

capt_paul

If you would just perform a search, you will find many, many responses to this same question.

GuidosGottaBenz

Here ya go

https://mbworld.org/forums/c-class-w...uggestion.html

splinter

2.3 or 1.8?

Probably wise to change them at their 100,000 or five year recommended interval.

M111 2.3 = NGK IFR6D10
M271 1.8 = NGK ILFR6A
Both are OEM-specified plugs.

They’re available from the dealer (with the sexy Mercedes logo) or OTC for less.
There is nothing to be gained from splitfire double whammy thunderbolt and lightning plugs.

Be aware the M271 requires a relatively unusual reach of 26.5mm/1.04”…the M111 a more conventional 19mm/.750” type.
Note that some in GuidoGottaBenz’s link installed incorrect reach plugs.

LILBENZ230

Hey Splinter, what do you mean by "relatively unusual reach"? Sorry for my ignorance! I'm getting ready to do the plugs on my C230 with the M271 and don't want my independent to run into any surprises. Are the ILFR6A plugs gapped properly when purchased? Thanks!

splinter

Not at all, Matt.
'Reach’ is defined as the length from where the plug seals against the external portion of the cylinder head casting to the depth of its business end within the combustion chamber.

A shorter plug will screw in just fine, although ignition efficiency is dramatically reduced. Downside is when the correct reach plug is finally installed, the fragile aluminum head’s threads are often damaged from chasing the inevitable carbon and combustion byproduct buildup that have been deposited on what should be virgin territory. Converse is irrevocably damaged pistons and valves. Either predicament is easy enough to avoid.

ILFR6A on the left and below; FR6D10 shown beside:





Gap specification for the M271 is .9mm/.036”; the M111 and M112 call for 1.0 mm/.039”. The ‘10’ suffix after the IFR6D denotes 1.0mm. QC is such that adjustment is seldom required. Don’t believe a thousandth or two spark plug gap means much anyway, unless you’re pumping more than 18psi of boost or chasing that last ounce of performance. Trust, but verify, is a reasonable approach. Should adjustment be deemed necessary, ensure that the center electrode is not disturbed – only the ground (side) electrode can be altered to change their gap.

Wasn’t my intent dissuade the OP from chasing more performance, only to reinforce that MB has already seen fit to furnish excellent plugs as original equipment. Had it not been for that meteorite depositing itself in the Yucatán Peninsula’s Chicxulub crater, none of us would be enjoying the performance and longevity benefits of iridium. Probably best I spare y’all those fascinating details for the geological forums.

Iridium is an exceptionally hard material that permits a very fine center electrode – substantially reducing ampere requirements to bridge the plug’s gap – while ensuring minimal erosion even after millions of arcs. MB’s OE plug compared with the $1.99 AC Delco copper-cored CR43TS’s renewed annually - every 30,000 miles - on my GMC..



Buy the best and cry once.

Norwichdelta06

my recommendation is always go OEM when going with plugs. You will never notice a difference in performance between 2 diffierent types of plugs. The only difference you can actually notice is chaning an old plug with a new one.

splinter

Received some funky PMs insisting I was full of manure for suggesting MB would source Japanese hardware.
A shame they didn’t have the wisdom to forgo their fault-prone Bosch electrics more often.

Sublet products wrapped in German packaging..





images credit komp55

Have utilized NGK’s excellent plugs since the first engine I successfully modified...in a '69 Hodaka Super Rat.

LILBENZ230

Whoever sent you PMs, I hope they read this thread. Nothing worse than someone who just thinks they know something while not researching it at all.