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prkaye

Well Known Member
I got my tachometer transducer from Vans. It didn't come with any directions. The first photo shows the transducer which has an AN style fitting with some kind of circular insert. It also came with a rubber washer. The second photo shows a fitting on my engine directly above my oil filter, that I assume this connects to. The fitting on the engine has a similar circular part inside.

1) Is it just a matter of putting the rubber washer in the fitting and tightening it on to the engine, or is there some procedure for engaging the center portions?

2) How does this thing work? I assume this thing gets spun, but I don't see how the spinning parts would get locked together... just through friction against the rubber washer (i.e. the washer is sandwiched between the two circular parts, so that when one spins the washer prevents slipping and so causes the other to spin with it) ?



 
I've never used one of those before Phil, so I am equally puzzled - sure seems like you're missing a piece!
 
There is a "spaded tang" that transfers motion from the engine to the hall effect module. I'll see if I can find a picture of one.
 
That one looks a little different from the one I've used, but I'd guess the principal is the same.

Look carefully through the packaging and see if there is a small key. It is a rectangular bar with a cross section maybe 1/8" square and about 3/4" long.

I can't tell from your picture but I assume there is a small square hole on the center of the spinning element on the sender to accept the key. It will correspond to an identical hole on the engine's tach drive. The key is a slip fit and doesn't attach to either side so it's easy to lose.
 
Phil,

You are missing the KEY. It was in the box. Looks like a broken
arrow or broken cable drive about 4" long.
I had to order the extension on mine because of the oil filter
and SD-20 that I will put on later.

Hope it helps.
 
Found the key! Thanks guys.
I assume there is a small square hole on the center of the spinning element on the sender to accept the key. It will correspond to an identical hole on the engine's tach drive.
Click to expand...

Actually the key is different on each end. (pic below) It looks pretty clear that the bigger end goes into the engine, and the narrow square-cross-section end goes into the engine... correct?



Next question... wires. There are 3 wires coming out of the transducer. White, black and red. Here's my guess... red - power, black - ground, white - a voltage indicating RPM that gets hooked up to the tachometer (or EFIS)?
 
prkaye said:
Found the key! Thanks guys.


Actually the key is different on each end. (pic below) It looks pretty clear that the bigger end goes into the engine, and the narrow square-cross-section end goes into the engine... correct?
Click to expand...

Yep! That's its! Basically, the little shaft is a drive shaft, make sure it works. Just to make sure you have the correct one (there are a couple of different sized ones, ask me how I know :mad: ) Take the "engine" side and put it in. You should not be able to turn it by hand, or said another way it should not slip. Then try the sender side, it should not slip or turn inside the unit without turning the innards of the unit itself. Does that make sense?

I spent weeks trouble shooting an erratic tach on a plane I bought. Long story short, it was this same tabbed connector that was the wrong one for the application. It was just turning inside without turning the hall effect sender.
 
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Key length too long

Be careful when screwing onto the engine tach drive as the key/spline was too long and popped the top off TachGen. I had to cut about 1/2" off the spline length.
 
OK, not quite sure how to hook up Vans' tach transducer to the Dynon. The tach transducer has three wires, black red and white. Vans' wiring diagram for hooking up gauges shows those three wires going into three terminals on the back of their steam RPM gauge, labelled S, G, and I. Now, the D-180 only wants one wire for the tachometer input. The Dynon documentation says for a standard tachometer transducer, to connect its "output" to the RPM Left input on the D180. But which wire is considered the output of Vans' tachometer transducer? Is the output of the transducer the White wire (which goes to the "S" terminal on the steam gauge... "S" for "Signal"?) ? Do I then just run the red wire directly to the battery bus and the black wire directly to the groundblock?
 
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