Bc 12d tach

[Jaymahan]

Hello, new to the site. I apologize if this has been talked about but have searched and found a lot of similar topics online but most relate to the cable. My tach seized up and the glass shattered. Mechanics have been unable to get it operational. The engine is the c85. Not sure if it matters but the gauge is clockwise needle rotation. So I'm looking for a new tach but standard tachs have the opposite fitting. Where would I find a tach that would just replace the one that broke. Found the post that someone mentioned a 90 deg elbow that is reversible. https://m.aircraftspruce.com/catalog...p?recfer=26590
Would this allow me to connect to existing cable and use a standard tach say from a cub that I have access to? Just trying to figure out the cheapest way I can monitor my rpm's again! Thanks in advance and sorry if this has been answered already.

[PA1195]

Re: Bc 12d tach

Hello from Fairbanks. Not a mechanic here but this is what mine's like. I have a C-85-12F with an accessory case starter that uses a clockwise tach driven by a right angle drive, but only because of limited space between the fuel tank stuff and the rear of the tach. I think early A-model Continentals and those later with a -8 suffix (no starter drive - hand prop) turned the tach cable CCW looking at the end of the cable from the cockpit, the C-85-12's turn them CW to match a CW tach (hope that's right as it makes sense to me). Start your engine or prop it dead and see which way the cable center rotates.

The angle adapter you linked can be used to match the CW tach to cable rotation if the input fitting is installed on one side (turn the input ferrule and see if the output rotation on the tach hookup side is the same). If the input fitting is removed and installed on the other side of the adapter (switches with the blind hole plug) it'll reverse the input and output directions CCW cable to CW tach, or CW cable to CCW tach.

Nice plane but the mountain's upside down.

Gary

[PA1195]

Re: Bc 12d tach

Pooooof! Jaymahan's inverted and gone like a cool breeze. Hope he respects what it takes to try to help someone. Whatever the Golden Rule means.

Gary