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Path: utzoo!watmath!clyde!cbosgd!ihnp4!pesnta!hplabsb!bl
From: bl@hplabsb.UUCP
Newsgroups: net.auto.tech
Subject: Re: Spark plug technology
Message-ID: <3163@hplabsb.UUCP>
Date: Tue, 12-Nov-85 16:27:16 EST
Article-I.D.: hplabsb.3163
Posted: Tue Nov 12 16:27:16 1985
Date-Received: Thu, 14-Nov-85 00:49:33 EST
References: <1856@watdcsu.UUCP>
Organization: Hewlett Packard Labs, Palo Alto CA
Lines: 35

> 
> As well all know (since we read net.auto.tech, right?), a spark plug
> has an end shaped something like the diagram below:
> 
> 
>                      |---------------\
>                      |-------------\  \
>            gap -->    _____         \  \
>                      |     |         \  \
>                      |     |          |  |
>                      |     |          |  |
> 
> Well, how about this design?  I found one of these just last night.
> Anybody seen it before?
> 
> 			     gap
> 			      |
> 			      |
> 			      v
> 
>                        |----|  |---------------\
>                        |    |  |-------------\  \
>                        |    |                 \  \
>                        |    |                  \  \
>                        |    |                   |  |
>                        |    |                   |  |
> 
> Where I found this was on my new (!) 1956 Porsche 356A 1600 engine.  I
> was disassembling it, and pulled the spark plugs to examine them.  I
> took me about three looks before I actually figured out why the plugs
> didn't look right.  Is this what all plugs used to look like 30 years
> ago or is this specifically a Porsche plug (they're made by Bosch).

Plugs like these have been used in nearly every piston powered airplane
ever built.