Pagoda SL Group

W113 Pagoda SL Group => General Discussion => Topic started by: Raymond on July 16, 2022, 13:30:26

Title: Spark plug extender???
Post by: Raymond on July 16, 2022, 13:30:26
Okay boys and girls, what the heck is this?  See photos.  I pulled these out of a cylinder head I was given.  It was removed from an early 280SL decades ago.  The plug with the "extender" on it was in the #3 cylinder.  Was this one of those 1970's gimmicks that was supposed to save fuel?
Title: Re: Spark plug extender???
Post by: wjsvb ✝︎ on July 16, 2022, 15:15:58
They were used to reduce plug fouling in engines that burned oil. Common in old "Stovebolt" Chevies and such.
Title: Re: Spark plug extender???
Post by: Jonny B on July 16, 2022, 15:42:29
Most interesting, always learning stuff.

Here are some background articles

https://www.easterneye.biz/things-to-know-about-spark-plug-non-foulers/

https://www.motorverso.com/spark-plug-non-fouler/


Title: Re: Spark plug extender???
Post by: Raymond on July 16, 2022, 15:59:12
Still seems a bit like snake oil to me.  But, you can surmise that the owner tried this, and whatever problem he had caught up with the engine.  Explains why the dealer replaced the engine.  Now, why did he keep the head?
Title: Re: Spark plug extender???
Post by: Shvegel on July 23, 2022, 09:54:30
The concept was if the rings were bad oil eas swirling up into the combustion chamber past the rings.  By shielding the spark plug you avoided getting coked up oil residue on your spark plugs.  They worked to a degree.  I think one of the best visual ways to determine ring sealing is to look at the piston tops.  If the edges of the piston tops are nice and clean it is likely that oil is washing up around the piston and misting the edges of the piston crown.
Title: Re: Spark plug extender???
Post by: Desertpagoda on July 25, 2022, 02:43:26
Thats an old school anti-fouling tip. It works by pulling the electrode up away from the combustion chamber. It absolutely works. We also used to use Aldor spark plugs in sick engines, they will fire even if soaked in oil.