great plains crank and aerovee primary ignition

[bz6200]

I've read a couple of posts regarding the great plains crank and aerovee ignition. I built my engine with the great plains crank & prop hub and we are having a heck of a time with the aerovee primary ignition. I read that it could possibly be the master dowel position causing the timing to be off in regards to the aerovee flywheel. I also read that Jay Gibbs built and engine with the same configuration. I would like to talk to him if possible does anyone have his contact info. Thanks , Jonathan Neal Sonex #0418

[vigilant104]

Jonathan,
Jay may chime in here soon, he sometimes monitors this board.
I am lucky enough to own Jay's plane now, maybe I can help? I've got one cylinder head off now, but if there's something I can report on just by looking, let me know.
I've sent you a PM.

Best wishes,

Mark

[frkatck@yahoo.com]

I've had to do an overhaul due to a broken crankshaft on my 2180 aerovee. I now have great planes force one crank shaft with the aerovee ignition per Hummel engines. When I first ran it a year ago it ran and flew great but I had a oil leak at the main seal. Tore down and replaced seal and now still a year later I can't get more than 1500-1700 RPMs on the primary ignition but can get 3000 RPMs on the secondary (static) I'm frustrated to say the least! Anyone lead me in the right direction appreciated.
Frank

[kmacht]

Have you checked with a timing light to see to see if the timing is the same between the primary and secondary? Its also possible you are only getting two of the four plugs to fire. The aerovee will run on two cylinders.

Tell us more about the broken crank. This is the first time I have heard of that type of issue on an aerovee and am curious as to the circumstances surrounding it.

Keith
#554

[SonexN76ET]

To get a Great Planes crankshaft to work on an Aerovee, you will need to make sure that the flywheel with the trigger magnets clock exactly the same way as an Aerovee crankshaft is clocked. This means when at top dead center on the number on cylinder, the trigger magnets/flywheel are in the same position that they would be if using the Aerovee crankshaft. How you do that likely takes some machine work.

Also, follow Keith's advice to make sure you are firing on both magnetrons if you have properly clocked your trigger magnets/flywheel.

Thanks,

Jake