Upgrading the Engine Monitor


JP Instruments EDM-700Adding RPM + MAP + USBJP Instruments EDM-830


The new JPI EDM-830 arrived from Aircraft Spruce. Since this instrument uses the same transducer harness as the existing EDM-700, I only needed to make a new mounting plate and run the new wires for the manifold pressure and RPM transducers.

The first step was to remove the existing EDM-700 unit and mounting plate, and fabricate a new one for the EDM-830. Since the EDM-830 uses an offset 3” instrument hole to mount through, I drew up a template on the computer, and printed this out on some paper, then glued it to the aluminum plate for cutting.

Old EDM-700 and new EDM-830 mounting plates

Instrument Panel Hole Cutter

Cutting the circular instrument hole was achieved with a special cutter. First, the center pilot hole was drilled. This was then stepped up to a 5/8” hole. The cutter was then bolted either side of the aluminum plate, and the bolt tightened….or rather: after several attempts on my own, I then enlisted my hangar neighbors to help – the resulting solution to tighten the cutting bolt was to clamp the metal plate in a shop vice, then use a large 15/16” wrench on one side, and a breaker bar on the other.

Rear view of the EDM-830 mounted on an aluminum plate

Front view of EDM-830 mounted on to aluminum plate

Once the hole was cut, I installed the EDM-830 to see if the sizing was good. The mounting holes for the bracket had to be opened up slightly to allow proper alignment – then I got a nice fit.

Next – prep, prime and paint the plate.
Primed Mounting PlatePainted EDM-830 mounting plate
The new EDM-830 has a larger display than the EDM-700 it is replacing. However, the weight of the unit is the same, and the depth of the unit is significantly shorter – this will make the installation a bit easier.

Back view of the EDM-830 (right)  and EDM-700 (left)

Top view of EDM-700 (left) and EDM-830 (right)

Front view of EDM-830 (left) and EDM-700 (right)

I need to finish the firewall so that I can get back in to the cockpit to install the EDM-830……