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robertc
05-21-2014, 05:37 PM
I need to put the cowling bumps on my PA11 project to allow for the shielded ignition. Do the bumps attach from underneath or on top of the cowling. I have seen them both ways, but I like the look when applied from under the cowling better. If attached from under, is there enough clearance? Last question; How do you blend the edges? Thanks.

tempdoug
05-21-2014, 11:13 PM
I like the looks on top with a nice bucked rivet job. Then you dont need to blend the edges. Also theres some shorter plugs you can use.http://www.supercub.org/forum/showthread.php?35590-shorter-spark-plug&highlight=shorter+spark+plugs

brown bear
05-21-2014, 11:22 PM
http://www.supercub.org/forum/archive/index.php/t-35590.html
Old thread, may help ?
Doug

nesincg
05-22-2014, 12:55 PM
I used these plugs UREM37BY

I almost didn't even need the cowl bumps but the ignition harness rubbed too much. Mounted from below and these plugs will be plenty of room. They could probably be half the height.

mvivion
05-22-2014, 02:32 PM
Mine are on the outside. Dunno if that was original.

MTV

nesincg
05-22-2014, 06:13 PM
The bumps were not original. They came when shielded plugs came along.

Sent from my SCH-I535 using Tapatalk

skipster
05-22-2014, 09:52 PM
Piper mounted them from underneath.