flyrotary@lancaironline.net Mailing List Archive

Charlie,

I meant to reply to your message a long time ago. I don't know what effect thermal paste on the spark plug threads would have. As long as it doesn't cause galling of the aluminum rotor housing, I don't see how it would hurt.

Having replaced the BR10EIX spark plugs after 180 hours of use with no indication of problems during that time, it appears that the lifetime of those plugs is at least an order of magnitude greater than what I was getting from the stock spark plugs. 91 octane non alcohol automotive fuel was used exclusively during that time.

Steve Boese

RV6A, 1986 13B NA, RD1A, EC2

From:	Charlie England <flyrotary@lancaironline.net>
Subject:	Chilled spark plugs: Thermal paste?
Date:	Sat, 20 Aug 2016 08:30:03 -0500
To:	Rotary motors in aircraft <flyrotary@lancaironline.net>

An article in Sport Aviation several months ago (which I just got around to reading; unusual to find useful info there) talked about Rotax's recommendations for spark plugs in their engines. One thing they require, in addition to using the correct heat range, was the use of thermal conducting paste (similar to what you'd put on a power transistor or computer CPU heat sink) to provide better/faster heat transfer from the plug threads to the head. Now, I've been messing with IC engines for around 50 years, and while I use anti seize religiously on my Lyc plugs, and occasionally on other stuff, I've never thought about using thermal paste. Must have missed a memo at some point in my past.

Recent and recurring discussions about needing colder plugs in high duty cycle rotaries, including Steve Boese's research several years ago, got me thinking about connecting the two dots.

Since I'm not flying yet, is there anyone out there who's flying a lot who thinks it might be worth a shot to see if it will extend the life of their already cold plugs?

Charlie