Logan -

The tach signal should continue to function as long as power is going to the brain box. You can do your "mag check" using that function on the box or killing power to the coil pack with the CB. If you are killing the whole system power, I think that's your issue.

So I'm installing my SDS. Found a temporary place for the control box on the lower right sub panel, test fitted the crank sensor bracket, drilled the baffle for the sensor cable, fabbed a shield to deflect a broken alt belt, etc. I've had a 500hr inspection on the right mag which will be retained.

Today I removed the left mag. The spacer is still tightly attached to the case. Before I go to the trouble of removing the spacer and replacing the studs, would there be an issue if I simply left the spacer attached, and bolted the cover plate to the spacer? The would save me the trouble of installing shorter studs.

BTW, what's the torque value for the case bolts? I'm mounting the coil to the top of the engine, and the front bolts loosened to mount the Hall sensor will need re-torquing.

No issue with leaving the spacer except a few ounces, less space and aditional leak potential. BTW, there is no requirement to replace the studs with shorter versions - bolts work just fine for cover plates. Getting the old gasket off is fun, as is removing the studs, but thats a one shot deal.

Methinks this thread deserves "sticky" status, lots of good info that should be easy to find.

1/4" perimeter bolts: 96 to 108 inlbs
3/8" case studs: 25 ftlbs
7/16" case studs: 35 ftlbs
1/2" case studs: 50 ftlbs

If you are pulling the left (impulse) mag and leaving the non impulse mag, you should take measures to prevent that mag from accidentally being turned ON while cranking as it will cause a kickback.
You probably knew this already
Tim Andres

I have individual locking toggles. Right now, the only countermeasures I have are: checklist procedures; panel labeling; and pilot knowledge (which is the weak link.) I know that there is a design out there that interlocks the ignition toggles, I need to find it.

Here you go:
http://www.vansairforce.com/communit...ad.php?t=36272
Post 5 has the links to Bob Nuckolls article and drawings
Tim Andres

The SDS CPI has a weatherpack-type 4 pin connector that joins the coil to a wiring harness to the cockpit controller and power. I want to hard mount the harness side to the rear baffle - is there a mounting accessory for these types of connectors? If I need to fab something, any suggestions?

I didn?t do this with my install but I wish I had. I think these Deutsch DT connectors are really nice. They have a flange Mount version that could be mounted to the baffle. I?m using these for wing root connectors. They aren?t cheap but they are good quality.

https://www.prowireusa.com/c-3-deuts...aspx?pagenum=3