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  #1  
Old 02-11-2007, 09:31 AM
Geoff
 
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Default Increase the gap REM37BY

My engine came from Mattituck with REM37BY plugs set at the standard gap, and it ran fine in the test cell. I'm using dual P-mags, and their documentation says to increase the gap to 0.030-0.035. Should I do this, or should I just leave them alone?

Assuming I increase the gap, I'm looking for some advice on how to do that without damaging the plug.

Spruce sells an "electrode spreading tool" -- part number 12-51520. Do I need it?

All of the tools and documentation I've found relate to decreasing the gap. That tool at Spruce is the only thing I've found to increase the gap, and I'm not sure of the mechanics of actually using it.

Can someone point me in the right direction?

I don't mean to start another aircraft vs. auto plug debate. Aircraft plugs are what I have -- I just want to deploy them properly.

Thanks.
-Geoff
RV-8
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  #2  
Old 02-11-2007, 09:49 AM
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Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,762
Default

I have several spark plug gapping tools that have an ear with a slot used to grab the ground electrode and bend it away from the center electrode. Unfortunately none of them have a brand name on them. The ACS tool looks like it is placed between the center and ground electrodes prying the gnd electrode away. I don't recommend this. You should NEVER apply pressure of any kind to the center electrode.
Another question that comes to mind is gapping the plugs to .030 with these ignition systems. The manufacturers should know what they are talking about, but don't these systems revert to "magneto" if EI fails? A normal magneto won't jump a .030" gap. I guess I don't fully understand the E-Mag/P-Mag system.
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Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
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  #3  
Old 02-11-2007, 10:06 AM
Martin Sutter Martin Sutter is offline
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Join Date: Jan 2005
Posts: 266
Default

The P-Mag is a totally electronic ignition system. It's back-up mode is a built in alternator affixed to the units drive shaft. This alternator provides power to run the ignition if the power from the aircraft bus fails. E-Mags, Light Speed and others do not have this self powered back up, Lasar uses a conventional mag to back up the electronics.

Martin Sutter
building and flying RV's since 1988
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  #4  
Old 02-11-2007, 10:08 AM
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Mel Mel is offline
 
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Location: Dallas area
Posts: 10,762
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Thanks Martin. Guess I didn't understand that correctly. I thought they went to "mag" for backup.
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Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
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