Author Topic: Spark Plugs 4.5 mm Thread  (Read 5793 times)

Offline Graham Meek

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Re: Spark Plugs 4.5 mm Thread
« Reply #15 on: August 09, 2014, 03:08:23 PM »
Digressing back to the spark plugs - what are you making the insulators out of? Am I right is assuming it's a plastic and you're retaining it by rolling or crimping the steel outer body onto the machined shoulder of the insulator?

AS

Hi AS,

The portion of the insulator on view is PTFE, retained as you have surmised. In the combustion space the insulator is a Ceramic Bead or "Fish Spine". The PTFE is used to form the gas seal between the ceramic insulator and the plug body. I am not overly keen on PTFE exposed to high temperatures in the combustion space. Experience gained whilst working on a tool to spray PTFE onto Fuser Rollers for a copying machine has put me on my guard where this material is concerned.

My best regards
Gray,


Offline Roger B

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Re: Spark Plugs 4.5 mm Thread
« Reply #16 on: August 09, 2014, 06:26:44 PM »
Foundry man's flu is not nice  :(
Best regards

Roger