Platinum Spark Plug Upgrade for Mercruiser 3.0

[mwnitz]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

Don S,

I tried using two NGK cross reference sites. Both sites show a 'TR5' as the NGK equivalent to 'MR43LTS' (my OEM plug). They show 'BPR6EFS' as the NGK equivalent to 'R43LTS'. What's the 'M' for that's missing in the second AC part number? I'm guessing the 'M' means marine and some sort of corrosion added protection on threads....?????

-MW

(edited due to typo)

 

[bruceb58]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

Platinum spark plugs started showing up in cars where certain models(mid engine mini vans) took literally hours to change the plugs. My Lexus GS is one of those cars where all of the intake manifold has to come off. Having the spark plug change interval increased to 100,000 miles in some cases is what required the technology. It wasn't done for increased performance although that may be a slight benefit.

 

[Bondo]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

What's the 'M' for that's missing in the second NGK part number?

Ayuh,... Donno about the NGKs,..
The "M" in the AC part #s are Marine,... It's an Alloy body...
No "M",... just a carbon steel body...

 

[Don S]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

I really don't like cross reference tables, they always seem a bit off to me.
The Mercruiser dealer site and the OEM service manual (#26 and downloadable in the adults only sticky if you don't have it) show the NGK - BPR6EFS as the plug to use, or the AC MR43LTS. They even show a Chumpion in there, but I won't tell you what it is.

 

[Tail_Gunner]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

You DO NOT gap platinum plugs. You gently check them, but you do not adjust them. They come pregapped and if too close, then they are damaged and should be returned.
If you look at that service bulletin, it recommends an AC spark plug for your engine, not a champion. The NGK equivalent is a BPR6EFS, not a platinum, but works great in those motors.
There isn't a Mercruiser recommended platinum plug for your engine.

Something knew is always coming up here..Don is the plug platium coated?? Why no gapping??

 

[JustJason]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

Why no gapping??

The electrode is plated. If you try to gap platinum, iridium, or unobtainium plugs the plating will peel off or crack. If it peels or cracks then the tip to electrode tab gap no longer is the point of least resistance, and the plug will fire (when it wants to) sideways and it will misfire like crazy.

 

[PiratePast40]

Re: Platinum Spark Plug Upgrade for Mercruiser 3.0

...unobtainium ...

Checked the chart of the nuclides and didn't see that one but can understand becauses we sometimes deal with quite a bit of BS'ium 210 in my line of work.