Champion W-20 plug
 

Would a Champion W-20 plug be a good runner in a Model A engine that probably has seen better days,probably needs at least rings and valve job,never bored. I have 4 W-20 that came with it.Thank You. Also have the 3X plugs.

Re: Champion W-20 plug
 

37 Coupe ,they are a industrial plug with a high heat range

http://www.federalmogul.com/digitala...RangeChart.pdf

Re: Champion W-20 plug
 

I have Champion W-18 plugs in my CCPU and they run fine. The chart that Jim B linked to shows they have a heat range of 7 which is the same as it shows for the W-20 plug, although the W-18 has a reach of 3/4" while the W-20 has a reach of 5/8".

Re: Champion W-20 plug
 

I noticed the shorter reach compared to the 3X plugs I have but also different plug gap design.

Re: Champion W-20 plug
 

The modern 3X plugs are a reproduction of the old ones and have the "bent wire" ground electrode which is designed to drain any oil accumulation away from the gap. The oil accumulation occurs in old, tired engines, aka oil burners.

Re: Champion W-20 plug
 

I use W-20's and have never had a problem with them. The engine in my Tudor was getting on a bit, and would get a bit fumy when hauling up a long climb, but the plugs never fouled.

Re: Champion W-20 plug
 

The shorter reach likely helps keep them from fouling for a oil burner.