----- Original Message -----
From: <13brv3@mchsi.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, March 28, 2003 6:13 PM
Subject: [FlyRotary] Re: Muffler packing


>
> On the plugs subject have you heard of  NGK SD10 A and 11 A.? Ian
> -------------------
>
> I'm curious about these as well.  As I mentioned earlier, these were in my
> engine as received from Bruce.
>
> Cheers,
> Rusty
>
>

I have heard of them in older rotary engines and may have been a racing
plug.  I could find nothing on the NGK SD10A, however, I did find a chart
that cross referenced them to ND-Denso plugs type S29.  The S in the SD
indicates a Surface Gap Plug made for the MAZDA R.E. (Race Engine??).  The D
indicates a four ground electrode very similar apparently to the Stock Mazda
Plug.  The "A" indicates a Dual ground electrode plug made fro the MAZDA
R.E.  The 9 or 10 indicated the heat range.   The SD9, SD10, SD10 A are now
cross referenced to the Denso Iridium plug number IRE01-27.  A part number
for the IRE01-27 is given as #5719, however, interestingly no its the only
plug shown with no specification data such as thread dia, reach, gap, etc.
Makes you wonder if it really exists.

 Don't know if this helps any.


Ed Anderson