Mark, I have flow over 400 hours using primarily 100LL.
For our use of the O2 sensor– that is for use as an Air/Fuel ratio indictor - the lead in the gasoline has no noticeable effect. My understanding is that continued use of leaded fuel can render the O2 useless for the purpose for which it is used in an automobile to keep the mixture at stoichiometric. There is a hysteresis response curve of the sensor that is important in performing this function and apparently the lead greatly impairs this function. However, for our use all we are interested in is the 0 – 1 volt output. Whether it occurs in 1 msec or 10 msec or 100 msec response time is undetectable to our human senses. In any case, I am on my second O2 sensor – not because the old one quit working but it did seem to be getting a bit less sensitive and the range did not seem to extend as far. So based on my experience, I doubt you have done any serious damage to your O2 sensor.
YMMV
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Tuesday, July 07, 2009 4:58 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: SAG - NKG
I had to resort to using 100LL on my recent trip from Austin to Denver and back. I burned a total of 56 gallons of 100LL. This was mixed with what was left in the tanks at the time (approx 40 gallons), so it was a blend of mogas and 100LL. I looked at the plugs after arriving back in Austin and observed a distinct whitish residue around the thread base, but none on the center or ground electrodes. It was still running fine when I arrived, and I refueled the following day with 40 gallons of Valero mogas. Most of my flying allows me to refuel at my home base, so it will probably be quite a while before I burn enough 100LL to make any reasonable assessment.
Quite frankly, I was more concerned with the effect the 100LL had on the O2 sensor. I didn't notice any change in my mixture readings though.
On Tue, Jul 7, 2009 at 11:26 AM, Kelly Troyer <keltro@att.net> wrote:
Be sure to update the group on how many hours you get on the Renesis (Iridium) plugs
before "SAG".............I know you primarily use auto fuel which will retard the onset of
"SAG" a lot but if you have to use aviation low lead periodically on X-country flights
you might figure what the percentage was of auto (versus) low lead used during the hours
before "SAG" reared its ugly head................
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from Mark Steitle <msteitle@gmail.com>: --------------
I've been running Renesis (irridium) plugs in my 20B with good results. Of course, they're about 5 times the price of the standard plugs. But if they last 5 times longer, I feel that they are worth the price.