Announcement

Collapse
No announcement yet.

Adding a tach to a continental aircraft engine with slick mag's

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Adding a tach to a continental aircraft engine with slick mag's

    Does anyone have an idea for a adding a tach to this thing on the cheap?
    This engine will not be in a plane so I am not wanting to spend the big bucks for the official air certified items like this https://www.aircraftspruce.ca/catalo...s/tach4cyl.php I am just looking to hook up a standard tach like this https://www.amazon.ca/CT-CARID-Tacho...motive&sr=1-12

    These things have built in coils so I dont think this will work? https://www.autometer.com/magneto-signal-converter.html
    The official sender unit in the above link screws into the vent hole on the magneto where there is a magnet that passes by every revolution. Would adapting a hall effect sensor work for this?
    I have very limited experience in this subject.
    Cheers,
    Jon

    Attached Files

  • #2
    I should add that there is a hub, seen just above the generator in the top pic, that is to drive a cable driven tach but that seems like it may not be the best route as the tach is going to be a ways away and a 180 from the direction of the port on the engine...
    Cheers,
    Jon

    Comment


    • #3
      yes, the tach drive is there. thats the old school mechanical tach, with a cable

      Comment


      • #4
        Dog clip???

        If there's a way to get a hall effect sensor close to the flywheel, then yes, 2 magnets at 180 will trigger any standard EFI tach.

        An older tach that's meant for a coil might need more than the 12v a hall effect sensor will swing,
        altho you might be able to attach it to one of the primary magneto coils and get it to work.

        t
        rusting in Seattle

        Comment


        • #5
          The sensor for the electronic tachometer is a hall effect type sensor. As long as this engine is not going to be used for aircraft you probably could adapt an automotive tachometer that uses a hall effect sensor. I know nothing except what I have read on the internet about this mag so you are on your own in selecting a tach and sensor. I think if you can adapt a sensor to mount in the vent hole you would be good. Look closely at the vent threads. I find reference to pipe thread AND straight thread in Slick Magnetos. Good Luck and let us know what you learn!!
          Robin

          Happily working on my second million Gave up on the first

          Comment


          • #6
            This may not be exactly what you are looking for since you linked to a large analog above, but it is an easy option and why I posted it.

            The digital inductive hour/ tachometers are very simple to hook up and most are very weatherproof. All that is needed to connect one of these to an engine is one wire, and that wire only needs a few wraps around a spark plug wire. That's it!
            The readout is powered by an internal battery and the pickup is inductive The only downside is that being somewhat on the small side they may not be as easy to read as a larger analog style tach.

            Home, down in the valley behind the Red Angus
            Bad Decisions Make Good Stories​

            Location: British Columbia

            Comment


            • #7
              The type I am used to are like so-
              https://www.amazon.com/ELING-Waterpr...755K34YN&psc=1

              These use a sensor-
              https://www.amazon.com/Universal-Sen...00PZI6IJO?th=1

              To read the teeth on a ring gear or tone ring. So if you have something availible on the engine that is turning 1:1 with the crank? It could be something as simple as a sprocket with the tips of the teeth machined off a bit.
              I just need one more tool,just one!

              Comment


              • #8
                Originally posted by Jon Heron View Post
                I should add that there is a hub, seen just above the generator in the top pic, that is to drive a cable driven tach but that seems like it may not be the best route as the tach is going to be a ways away and a 180 from the direction of the port on the engine...
                Cheers,
                Jon
                You do not have to use a cable. You can put a tooth wheel and sensor on that stub and use it for the Hall effect output just as well as putting a cable there. No need to dig in and find a spot elsewhere in the engine to put it.
                CNC machines only go through the motions

                Comment


                • #9
                  Originally posted by Willy View Post
                  This may not be exactly what you are looking for since you linked to a large analog above, but it is an easy option and why I posted it.

                  The digital inductive hour/ tachometers are very simple to hook up and most are very weatherproof. All that is needed to connect one of these to an engine is one wire, and that wire only needs a few wraps around a spark plug wire. That's it!
                  The readout is powered by an internal battery and the pickup is inductive The only downside is that being somewhat on the small side they may not be as easy to read as a larger analog style tach.

                  Yep, I am willing to bet that will do it.

                  Comment


                  • #10
                    How about something like this one. https://www.ebay.com/itm/16481530364...3ABFBMmLP-0btf

                    Just put the flag on the back of the prop hub.

                    Comment


                    • #11
                      Thanks folks. This thing will be exposed to the elements and needs to be somewhat rugged so I am steering away from the cheap inductive type. I also have a shielded ignition so I would have to cut into the shield to install the inductive pickup.
                      That last link from I Make Chips looks like it would do the trick I just need to figure out a mounting...
                      Cheers,
                      Jon

                      Comment


                      • #12
                        Originally posted by Willy View Post
                        . . .All that is needed to connect one of these to an engine is one wire, and that wire only needs a few wraps around a spark plug wire. That's it!. . .
                        Willy, aircraft plug wires are shielded. Do you think that would be problematic with the wrap-around sensing?

                        Southwest Utah

                        Comment


                        • #13
                          Originally posted by chipmaker4130 View Post

                          Willy, aircraft plug wires are shielded. Do you think that would be problematic with the wrap-around sensing?
                          Yes it would indeed be an issue, an issue I had completely forgotten about when suggesting this type of easy hookup.Can't say I've ever tried it but would bet serious money it won't work with shielded wiring. Completely overlooked that....DUH!
                          Can you hear the big dope-slap to my forehead. LOL

                          Lots of good other options laid on the table here though, however make no mistake these are very rugged outdoor oriented units, I have a number of these on outdoor power equipment and they regularly see rain and hose-downs without issue.
                          Home, down in the valley behind the Red Angus
                          Bad Decisions Make Good Stories​

                          Location: British Columbia

                          Comment


                          • #14
                            All different kinds and styles to go you just have to hunt them down - like Willy stated inductive pick-up around a spark plug wire, there are also ones that you just glue and magnet on a hub and install a pick up coil to close proximity and I believe you can do the same thing with another type that you just stick some kinda reflective tape on a hub and install a different type of sensor....

                            Comment


                            • #15
                              Originally posted by Willy View Post
                              Yes it would indeed be an issue, an issue I had completely forgotten about. . .
                              The shielding is for RFI suppression because of the nav and comm equipment on board. I suppose there may be a way to replace the rated wires with a conventional automotive type, although the terminations are, as I recall, quite different. It's been 45yrs since I got out of A&P school and I never worked as an aircraft mechanic so my memories are likely suspect.

                              Southwest Utah

                              Comment

                              Working...
                              X