Mailing List flyrotary@lancaironline.net Message #59061
From: Andrew Martin <andrew@martinag.com.au>
Subject: Re: [FlyRotary] Re: Heat ranges
Date: Tue, 9 Oct 2012 15:50:43 +0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Neil

SAG = sparkplug attention getter, generally causes one to ingest the seat cushion with your nether region!
plenty in the archives about it, invented I believe by Ed Anderson.

Apart from the missus car and a bike, everything on my farm is diesel also. so you should have seen the look of surprise I had when first starting this engine with built in electric fence energizer powering it. I swear I only had my finger on the starter for about a second before it roared to life.
SAG is basically the same as something shorting out the fence, basically electric doesn't get to where its needed.

We may have to have a friend in US to source the racing plugs, about $150.00 a set of 4 NGK R6725's in Aus.

Andrew

On Tue, Oct 9, 2012 at 1:39 PM, Neil Unger <neil.unger@bigpond.com> wrote:
Could someone inform this ignorant peasant as to just what SAG is actually. I can only gather it is something nasty. I am more at home with diesels.  Neil.
 
Sent: Tuesday, October 09, 2012 3:39 PM
Subject: [FlyRotary] Heat ranges
 
 
I hate to keep beating this drum, but if you can walk into an Autozone and buy it, you shouldn't.
The heat range is too high. Street plugs have nose temps high enough to keep crap burned off at idle speed and 2,000 RPM light throttle. Once you are at WOT for more than a few minutes that street plug is too hot. You get cement boil around the center post. You manufacture a glow plug and loose control of ignition advance.
 
The NGK dash 10s are closer to ideal. the dash 11.5 is what racers use. Crosses to the dash 10s are also used in racing. Cheaper racers use Autolite AR2592. Special order from your friendly parts house. The last ones I bought were $7.00 for 4 plugs. Next day delivery. If you live near a circle track they may stock a few boxes. Air cooled dirt bikes use similar heat ranges.
 
Use inductive plug wires to kill off radio noise. Keep plug wires as short as is possible. Plug wires must touch nothing that is grounded.
 
Lynn E. Hanover
Incinerating rotary
engines since 1980.
 
In a message dated 10/8/2012 10:26:43 A.M. Eastern Daylight Time, echristley@att.net writes:

David,

Thank you for the compliment.

I have installed a set of the -10 spark plugs and at this point they are long past the time where the stock plugs normally needed to be replaced. How long they will continue to work is unknown, but at least that one data point is consistent with the study and encouraging.





--
Regards

Andrew Martin

+61 0427477144
+61 8 6365 5648
+61 8 9924 1145
andrew@martinag.com.au




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