For some reason, Lycoming shipped the engine with an extra fitting in the fuel spider. The Vans plans warn about checking for this fitting and removing it. Unfortunately, the fitting can’t be rotated, as there is interference with the engine case. So I had to remove the spider, remove the fitting, install a plug, and reinstall the spider. This ended up being quite easy.
Over the weekend I took some time to seal up all of the visible air gaps around the baffling system. To help find and plug the gaps, I put a lead light on top of the engine, then installed the top cowl. I had to reposition the light a few times, but it did a nice job of finding many little gaps that needed to be filled with RTV.
This had to be done at night to ensure the garage was dark enough, but that works well since I’m typically working at night.
Tonight I switched out two engine case bolts for longer versions. These are specific bolts, ordered from Lycoming, and are 1/8 longer than the originals. The Vans plans have you place a washer and a cushion clamp on these bolts (one on each side), and there aren’t enough threads showing if you use the original bolts. The clamps hold the starter lead on the left, and the alternator power wire on the right.
Replacing the bolts was fairly easy. The cushion clamps always a pain, but I was able to get enough fingers in there to make it work. The nuts are torqued to 96 inch pounds per Lycoming.
It’s hard to reach the prop bolts with a regular crowfoot, so I bought a special prop-torque crow foot. I looked at a few options and decided on the Anti-splat Aero tool. It’s well thought out and did an excellent job. There’s a good video here that shows the tool in action.
The first step is to torque all bolts to 40 inch pounds, then to 60-70 foot pounds as the final torque. With the extension tool, I calculated 35 and 57 foot pounds. I measured the length of the arm of the torque wrench and the length of the extension and used the formula T1 = T2 * L1/L2 where T1 is the torque on the wrench, T2 is the target torque value, L1 is the arm of the torque wrench and L2 is the arm of the torque wrench plus extension.
Then final torque to 60-70 foot pounds (calculated as 57 on the tool). by holding the prop in one hand and torquing with the other I was able to torque all 6 bolts up myself.
The next step is to safety wire these bolts in pairs. That will be challenging due to the orientation of some of the bolt heads. Undoubtedly I’ll need to back some of these off to thread wire through and then re-torque.
Tonight I finally torqued the various nuts, and installed the cotter pins, on both the throttle and mixture cables. I ended up with slightly more cushion gap than ideal, but I think that’s ok. The mid-point of the cable travel is nicely aligned with the midpoint of the arm travel on the fuel servo.
Today I tested the clearance of the prop against the spinner, by rotating the prop between full fine pitch and full coarse pitch. The clearance was good, and never closer than about 1/8th of and inch. I
followed the plans and clamped two boards to either side of the prop and rotated using the boards as leverage. Since it’s hard to twist the prop and simultaneously observe the gaps around the prop, my son Julian helped me verify everything was good by taking pictures.
With that task done, I final drilled holes for the spinner cutouts and then riveted them into place.
Tonight I used RTV to secure the two emag blast tubes. These tubes direct air from the engine compartment onto the magnetos, helping cooling the magnetos during engine operation. I’m contemplating adding a blast tube to the alternator, but I’m concerned about moisture being blasted into the voltage regulator on the back of the alternator. This would be a problem when flying through clouds for example. The alternator is up front, but the emags are at the back of the engine. The emag blast tubes are less susceptible to moisture because of their location, so I’m not worried about them.
Tonight I worked on securing the throttle and mixture cables. Previously I had routed the cables and loosely coupled them. I had the lever travel worked out so I had a sufficient gap at the full forward position, and at half way through the travel the levers were halfway between fully open and fully closed.
The task was to torque the various fittings which I did.
Tonight I torqued up and safety wired the alternator belt. To help apply tension I found a steel rod, slipped a silicon cap over it, and used it to level the alternator away from the engine. This worked fine, and I was super careful not to damage anything.
It took a few goes to get enough tension to pass the slip test. This is where the nut on the alternator pulls is rotated to see how much torque is needed to slip the belt on the pulley. For a new belt it is around 11 feet pounds (the number is in the lycoming manual), and I found I was almost at the end of the tension slot to get that much tension on the belt.
Once the tension was set correctly I torqued back up the bolts and safety wired where needed.
Over the weekend I finished all of the wiring in the engine compartment, and added clamps to hold everything in position. I also modified the wiring behind the instrument panel, allowing a more direct path for the control cables, particular the prop control.
The last task remaining for engine compartment wiring is replacing the main battery wire which brings power from the battery solenoid to the V-PX. I’m upgrading from the Vans supplied #8 AWG wire to a large #6 AWG wire. I had to order new ring terminals from aircraft spruce, so I will finish that job once the terminals arrive.
