Dennis Jones

Spark Plugs for a 1933 Chevrolet Master 206 cu

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Does anyone know what a modern equivalent of the AC C86 spark plug would be?  I ordered new plugs for my 33 Chevy Master from the Filling Station and they sent me AC Delco R45 plugs.  They are completely the wrong size plugs.  Here is a picture of one of the plugs from my engine next to the Filling Station plug.

 

Thanks,

Dennis

20190314_185604 (Medium).jpg

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Obviously they don't know S*** from shinola. The * tells you that the threads are 18 MM and the 6 is the heat range.  If it were my engine I would use NGK  AB-6 plugs.  When I used AC or Champion plugs I had to clean and re-gap them at 5,000 miles and replace them at 10,000. When I was driving almost 1,000 miles a month that was a lot of bother.  Since I have changed to NGK, I just replace them about every 20,000 miles and have been doing so for over 300,000 miles.  By the way I found the plugs in stock at the local Porsche Dealer at almost half price compared to NAPA.

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According to the chart I found on the www the C86 crosses to:

 AC_DELCO     AUTOLITE
C86     375
C86     2697
C86     375
C86     377
C86     375
C86     386
C86S*     386
C86     2775
C86     3035
C86     3035
C86     3035
C86     3035
C86S*     3136
C86     376
C86     375
C86     386

 

BOSCH_STK.     BOSCH
7548                    M8AC0

champion STK 514, 515 or 516; Champion D14 or D16;

NGK A6

 

These are 18 mm plugs with 12 mm reach and a 1" hex.

 

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C87 is the current plug number and the filling station has them. Why not call them up and swap them out?

 

Dave

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Contact the vendor, mistakes happen.  I’m sure they will help you out.

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Another option would be to clean the old plugs, gap them, and continue to run them. Two of my cars run much better with period plugs than they do with modern replacements.

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I'm using Champion D16 plugs gapped at .040" with great success .

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