Thursday, June 23, 2016

Exhaust Temperature Probes Installed & Prop Bolt Woes

While the Loctite 241 used to glue the S-1207 bushing into the spinner cured, decided to continue chipping away at small tasks along with preparing items that will be used for the oil line purging process which will remove air from the Rotax’s oil lines and internal oil galleries and replace it with oil. Photos of the setup will be posted when the purging takes place. Another small task that needed finishing was instillation of the two exhaust temperature probes.

The two Dynon supplied exhaust temperature probes for the Rotax 912ULS engine are to be inserted into predrilled holes in the #3 and #4 exhaust pipes. The temperature probes come with a machined flange that only allows the probes to be inserted into the exhaust pipe to a pre-determined depth. A band clamp is part of the probe and wraps around the exhaust pipe ... when tightened around the exhaust pipe, the band clamp pulls down on the probe’s flange to keep the probe firmly seated to the exhaust pipe. Instillation is quite easy, in that the probes are inserted into the exhaust pipe, the band clamps are wrapped around the exhaust pipe and tightened down … presto done. Well not quite, the wires from the probes need to be wire tied in place.  I found this to be the most time consuming part of the task, especially for the #3 cylinder because after being attached to an adjacent water line with wire ties and routed aft, the probe wire is wire tied onto the fuel supply line and follows it upward … unfortunately, there is only room for one hand to get to this area. I found a hemostat was quite helpful here to act as a second hand  to hold the wire tie at a few locations.
Tightening the band clamp to keep the exhaust temperature probe for the #3 cylinder firmly seated in the exhaust pipe.
Routing of the #3 cylinder’s exhaust temperature probe's wire aft along the water line.
Not having room for a second hand, using a hemostat to hold one end of a wire tie worked quite well to get the wire tie started ... then the hemostat was moved to help pull the wire tie snug to secure the #3 exhaust temperature probe wire onto the fuel supply line.

Installing the #4 cylinder’s exhaust temperature probe was much easier, in that, the probe’s wire follows the fuel line for the left carburetor … which is totally in the open with great access for the wire ties. At the midway point on the engine, the probe wire is routed aft along the fuel supply line to the spade connectors that will connect the exhaust temperature probes to the Dynon EMS (Engine Monitoring System) in the instrument panel.
Wire for the installed exhaust temperature sensor for the #4 cylinder runs adjacent to the fuel line for the left carburetor and over to the red spade connectors in the background that run to the Dynon EMS.

Prior to beginning the purge test or completing the spinner instillation, the propeller needs to be installed …  so the Sensenich propeller box was opened and parts pulled out to complete the instillation. Another bump in the road was discovered, in that, a bolt of the wrong size was shipped with the propeller. Unfortunately, this was not caught at inventory time because the propeller hardware was left in the bag and only the bolt heads were counted ... so I’m partially to blame for not catching this much earlier. In this case, the propeller and mounting hardware is supplied by Sensenich … NOT Van’s. The problem is Sensenich shipped an incorrect AN4 bolt instead of an AN5 … plus it is way too short. Even though Van’s did not make the screw-up, they are going to send out a replacement AN5-15A bolt ASAP. Below is a photo of the parts that came with the propeller from Sensenich.
Propeller mounting hardware as received from Senenich. Note the bolt in the far right is NOT correct … it should be the same size as the five to the left of it.

While waiting for the bolt to arrive from Van’s decided to look ahead and discovered the engine controls utilize two Adel clamps … one attaches onto the engine mount and the other clamps around the control cables. Discovered the way the oil return line was routed it was somewhat in the way … so it was moved to the right side of the supply fuel line to free up the space for the Adel clamps on the left side of the supply line. Installing dual Adel clamps can often times be a challenge, but fortunately there was just room enough for my Adel clamp tool which really came in handy to hold the Adel clamps together so a screw and nut could be started. The screw will be left lose until all the control cables are installed.
Installing the dual Adel clamps that will support the throttle and choke cables for the Rotax engine. Fortunately there is enough room at this location to use an Adel clamp instillation tool which keeps the bottom Adel clamp compressed together so a screw and nut can be installed through the upper clamp without a fight.