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Dare I? Lightspeed III question

cbennet1

Well Known Member
I have a single LS III with the mini sensor for crank timing. Works fine.

I need to remove the engine for engine mount work which means I either disconnect the sensor at the box in the cockpit and deal with enlarging the firewall hole to squeeze the DB9 connector through (I disobeyed Klaus and disconnected the wires from the connector and reattached during initial installation) OR REALLY risk it and snip the 6 wire conductor and then use a low resistance connector to reconnect the sensor cable when done.

The basic question for this august body of builder/pilots is have you cut/reconnected the signal cable and what was the result? Did it work, did you end up buying a replacement, etc?

I promise to keep your identity secret. :D

Craig
 
You don’t need to do either. I have single LSE II and a few years ago removed my motor without doing any of that. I simply disconnected the sensor board from the fly wheel, placed it in a plastic bag and set it up on fuselage in front of wind screen, still attached to the wires. I don’t know if you can visualize this, I can attach a photo if necessary.
 
Dual P-II on my plane. Cut the cables where they penetrate the firewall and installed a 38999 round mil-spec connector with crimped terminals. Makes it very easy to remove the engine with sensor installed.
 
Thanks guys, very helpful.

Tandem46 - I know exactly what you’re suggesting and that would certainly work but in my case, I’m not removing any baffling or the prop so reinstalling the sensor with the proper gap to the timing ring looks tricky.

Craig
 
Can you de pin the DB connector, or is it a soldered version? If its crimped contacts, the demate is easy. After that just pull the wires through the hole in the firewall. Also might consider pulling the connector out of the backshell and see if it will fit through the firewall sideways.
 
Connector

It’s soldered. I did use that technique when I originally installed the ignition in order to avoid enlarging the firewall hole.

I have a bad back and another parameter in play is attempting to reduce or eliminate twisting in to a pretzel in the cabin at the back of the firewall.

Lazy, right!?! :rolleyes:

Craig
 
Don't be afraid...

I cut the ends off and re-terminated all the connectors using MIL-C/DTL machined crimp terminations and D-sub back shells.

Just don't tell anyone :)
 
dsub pins in heatshrink

I have the older style (bigger) flywheel sensor on my Lightspeed. When I built the plane, I cut the sensor wire in a convenient spot FWF and then installed crimped Dsub pins "inline", individually covered with heat shrink tubing. If I ever need to remove the engine, I just have to slice the heat shrink and disconnect the pins. Plane has been flying for 8 years and almost 900 hours this way with no issues.
 
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