flyrotary@lancaironline.net Mailing List Archive

Bob, I didn't even know there was a difference in length. They obviously work OK in the Renesis and since I used them in my 20B (with 13B turbo rotor housings) there does not seem to be a problem there either. The iridium plugs I used do not have the notched shell. They were pulled from early 2004 Renesis engines so I guess NGK made that change later.

I have never tried changing plug heat ranges since the standard plug recommended by Mazda has always worked OK for me. Flying at 7000 rpm (or less) is a lot different than racing at 9500 rpm of course.

Tracy (endless wiring of RV-8 panel)

----- Original Message -----

From: Rogers, Bob J.

To: Rotary motors in aircraft

Sent: Monday, December 11, 2006 3:59 PM

Subject: [FlyRotary] Re: MSD coils - Plug Fouling... again.

Tracy,

I noticed that the sparkplugs for the RX-8 (Renesis) engine have a longer reach for the leading plugs (21 mm) than for the trailing plugs (3/4 inch =19.05 mm). The earlier 13B engines all use a 3/4 inch reach plug. See the attached web pages:

http://www.ngkcom/results_app.asp?AAIA=1192340

http://www.ngkcom/results_app.asp?AAIA=1431319

Does the longer reach of 21 mm create any problem for use in the older 13B engines? If one wanted to run a hotter plug in the trailing position, will the longer reach (and hotter) leading plug work in the trailing plug hole?

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook
Sent: Thursday, December 07, 2006 8:35 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: MSD coils - Plug Fouling... again.

.

I changed my plugs to iridium type (stock Renesis parts) about 210 hours ago and they have been wonderful. Never a hint of 'SAG' but I have run only a few tanks of 100LL during that time.

.