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Your welcome Ed,
At Kawasaki we learned this problem the hard way. Late 1970's consumer OTC platinum plugs were just becoming affordable. The Kawasaki 900 Z-1 and later variants were starting to run poorly about 500 miles after tune ups. They had the floating secondary coils. We found a lot of the dealerships were putting in the platinum plugs. They made more money on them than the standard plugs. Lots of hair pulling was caused. The plugs DID WORK BETTER AT FIRST. They just went away very soon. If you know somebody with a soobie powered plane using the original coil packs they were the same way. I mentioned it to a guy at the Golden West Flyin, running a older soob in a Glasstar and watched the light bulb come on. He always wondered why 2 of his 4 plugs failed first even though the cylinders always had good compression and ran great to that point. I really like the small coil on plug set up, better spark and no firing backward!
Bill Jepson
-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, Jul 7, 2009 12:43 pm
Subject: [FlyRotary] Re: SAG - NKG
Boy, thanks, Bill
Never would have even occurred to me to watch out for mushrooming fine wire electrodes – the knowledge and experience on this list is fabulous!!
=0
A
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
Mark,
One thing to watch out for on the fine-wire plugs, is NOT to run dual lead coils. Some of the systems for the 20B fire both plugs at the same time. This isn't a problem, but some of the engine management systems use 3 coils with dual high-tension leads to make things simpler. Since most of the dual-lead coils use a floating secondary one plug fires normally and the other fires BACKWARD sidewire to center electrode. The plug that fires backward will wear the center electrode out faster. That isn't a problem with standard plugs, but on the high end platinum or iridium plugs the center electrode will erode or mushroom on the end. We saw this all the time on 4 cylinder motorcycle engines where they always used 2 dual lead coils to make the system cost less. The newer high performance bikes have gone to coil on plug designs, and switch the low tension side to eleiminate the problem.
Bill Jepson
-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, Jul 7, 2009 7:25 am
Subject: [FlyRotary] Re: SAG - NKG
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.
Ed, it appears to me that the NKG report is suggesting that we use hotter spark plugs, has anyone tried this. JohnD
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