Removing carbon from piston tops

[swalve]

The autolite plugs have a 'pp' in their part number if they are double platinum. Single 'p' is single platinum.

 

[Winston]

The only noticable benefit from using platinum plugs on a stock engine would be longer life. On many engines with hard to change plugs, that is a significant benefit. Otherwise it is not.

 

[The Critic]

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Out of curiosity, why do you say that the carbon on the pistons is ok? As far as doing the cleaning before removing the plugs, it was not feasible since Monday was really the only day I had scheduled to work on the car, and the engine had to be cold to do the spark plugs.

I dumped all sorts of cleaning stuff into the Expedition, via the brake booster vacuum line a couple years ago. Shortly thereafter, I changed the plugs. I could find no signs of fouling or anything else out of the ordinary, so it didn't concern me to do the cleaning on the VW with new plugs. FWIW, I think I'm done with trying to clean the VW via a vacuum line; it just scares me too much.

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Having the "APP" preceding the Autolite Part # tells you that the plug is a double platinum.

I just suggested doing the cleaning before putting in the new plugs as any carbon you may remove might needlessly contaminate and degrade the performance of the new plugs.

The Carbon is OK in my opinion as the engine was not designed to run without shiny piston tops…engineers who designed your VeeDub know that the piston tops aren’t going to stay sparkling clean and have figured that the carbon is probably harmless to a degree…or else they’d ask that you clean it up (in some way) on a periodic basis if it would significantly harm the performance.

No signs of fouling…??? Well, I guess you don’t have emission inspections in AL. Here in CA, I do ANYTHING I can to optimize my vehicle’s combustion efficiency given our ultra strict emission rules. Every little bit helps…and I’d rather not take chances with fouling the plugs even slightly if it could cost me a failed smog inspection.

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In your opinion, what effect does the MMO in your fuel have on the fuel's octane rating?

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No clue, but considering how expensive Catalytic Converters ($700+) and Oxygen Sensors ($200+) are, I wouldn't risk it.