Has anyone installed the over voltage protection (crowbar) device kit  from B&C specialty?  I can't seem to figure out how it is supposed to be wired.  It came with a wiring diagram, and to many people I am sure it makes sense, but I do not completely understand it.  I have a corvair installation with the standard 20 amp dynamo. Can someone offer any help?  Thanks,

Brad Boon

Greenwood, WI

601 HDS

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Can you post the schematic for me or email me the directions?  I should be able to "dumb it up" for you.  Thats not a dig on you.  I dont get stuff alot and as soon as someone explains it for me real simple and real life, AKA "dumb it up" it makes sense. jessehart05@yahoo.com

Hi Brad,

If you drop me an email at dgardea@gmail.com I will send you my wiring schematic that includes the over voltage protection from B&C that I installed for my Corvair.



CH650 / Corvair - 210 total hours

Indianapolis, IN

I have that crowbar installed...I can work with Jesse (below, he hangars right next to me) to draw up a harness diagram if you still need it.



Thanks, I will need all the help I can get.  Right now Dave is getting me his schematic so I will check that out first.  I would like to actually see some other Zodiacs for a change.  I have been working on my project steady now and its getting to the point where I should go and look at some other examples in order to finish it out.  I am getting the fifth bearing put on my crankshaft right now, its a Dan Weseman generation II bearing.  After that, I can start putting my engine back together.  Then, all that's left to finish the plane is wiring, canopy, baffling, cowl, spinner, interior and panel.  Ha ha, I have a long way to go!  Thanks again,


Did you get your question answered relative to the over-voltage protection? If not here's my diagram. Hope it helps.


Hi Rich,

Yes I have a pretty good handle on the wiring for now.  Thank you for sharing your diagram.  Its always nice to see more then one.  I do have a couple questions.  

1. What kind of electric primer are you using, where did you get it?

2.  Does the TP Selector Sw also control which tank the MFD displays the fuel level for?

3.  are you using the WW recommended starter?  I see you are using a separate contractor?



For the primer I used a spare Facet fuel pump I had but found fuel would siphon through the pump while the engine was running so I added a 05-04368 12V Solenoid Valve 751-50010 from Aircraft Spruce to the outlet of the pump. This works well but I only have it feeding the left bank, it would be better to primer both sides.

Yes the TP selector switch selects either wing tank fuel gauge for the EFIS and the associated transfer pump which feeds the header tank.

The starter came from WW and yes I'm using a separate contactor, there are pros and cons to both using and not using a separate contactor. Using one seemed to be the preferred method at the time.

So..... The crowbar dead shorts? And causes the field breaker to trip? And why dose the "batt/alt. master" title have a line thru it? I'm to curious I know


"So..... The crowbar dead shorts? And causes the field breaker to trip?" Effectively yes, works pretty well to. I had a bad voltage regulator which caused the breaker to open as the voltage rose to 16 volts.

"why dose the "batt/alt. master" title have a line thru it?" It's not supposed to, that occurred with the conversion to PDF.


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