Lycoming Service Bulletin No.632

While we were in Oshkosh, WI for the annual EAA convention, Lycoming announced a manditory service bulletin for about 1300 engines that had been manufactured in 2016, plus all engines that had been overhauled with new piston rods around that time.  Our engine serial number was one of those listed.  The inspection involved purchasing and using a special tool to find those connecting rods that may have looser than specified bearings in their upper ends.

An FAA Airworthiness Inspector friend who once owned an aircraft engine overhaul shop helped me get the job done.

Lycoming S/B 632 Inspection

The photo shows the tool (a big coil spring attached to the #4 cylinder’s rod.  If the bearing starts to slide out when the spring is compressed by six turns of its inner bolt, it fails.  We were lucky all four rods passed.  Note the red cylinder base o-rings that are used to keep the connecting rods from flopping around during the disassembly. The S/B was just a PITA that slowed progress by three days.

August 10 to August 29, 2017

The Garmin G3X Touch Configuration Menu starts here

Soon after the wings were mounted the FAA approved a Registration Certificate for Vans RV7 N50KB, known to us as “The Dream Weaver”.   That didn’t reduce the number of tasks yet to be accomplished.  I next

  • installed gussets connecting the fuselage side skins to the wing main spar. Two of the 1/4″ bolts were too short and were replaced by Vans.
  • Installed the 22 #8 screws that attach the lower wing skins to the fuselage bottom skin
  • Bolted the wing rear spars to the center rear spars.  This required removing and reinstalling the flaps.  Flap push-rod lengths were adjusted to synchronize the two flaps.
  • Connected aileron push-rods to the center section controls
  • Installed the outside air temperature probe onto a right wing inspection plate
  • Confirmed the angle between the wing top skin and the flap top skins are 45 degrees when in the down position
  • Identified, tested, labeled and prepared the 28 wing light wires for connection to a terminal strip under the PAX seat.  The LED landing lights draw 13.3 amps and were assigned a 15 amp breaker in the VPX Pro electronic breaker box.
  • Worked through the Garmin menu structure to find the VPX control page on the MFD screen. 
  • Then connected the VPX box’s serial port to my laptop computer and configured the breaker ratings for each circuit.

    A VPX Pro Configuration Screen on a Laptop Computer
  • Set the graphical image colors and limits for the Garmin screen’s graphical flap, fuel, and trim position indicators.
  • Threaded the pitot and AOA tubes up from the left wing root through the armrest support and on to the instrument sub panel where they were connected to the #1 and #2 ADAHRS units.
  • Filmed the ease of flight control movement.
  • Installed fuel lines between the wing tanks and the fuselage manifold.

Then it became time to do the inspection required by the newly announced Lycoming Service Bulletin #632.

The Flightless Bird Grows Wings

Waiting for Wings

For over a year, the wings have sat in their cradle waiting for this day.  Working on the fuselage was easier without the wings attached.  The day came when the next step in wiring was to connect the wing mounted taxi, landing, navigation and recognition lights.

I asked several RV friends to help Dolly and I with the job.

Getting Ready

Word spread around the airport and a gaggle of help arrived.  Knowing I would be in the cockpit driving close fitting bolts connecting the wings to the center section, I told everyone that Dolly was the floor manager for the operation.  She had helped when we did the test fit of the wings a year earlier.

Before mounting the wings, we sorted out the coils of lighting wires and fed them into the fuselage.  We started with the left wing.  Both wings had been laid out on padded sawhorses next to the plane.  This was for safety in case we had to halt the process mid-way to completion.

In 2016 the wings were test fit and retained with lubricated drift pins that I had made from hardware store bolts in a mini-lathe.  Now for each wing, two drift pins were driven in bolt holes before driving the first close tolerance bolt.  The pins provide initial alignment and are then replaced by bolts. 

There are a total of eight 7/16″ and eight 1/4″ close tolerance bolts holding the wings to the fuselage center section main spar.  They give one confidence in this aerobatic airplane.


When the wings were on we all enjoyed a great lunch of Subway sandwiches and cool drinks that Dolly had laid out. 

All in all, it was a great day!



Back to Building

May 2017 to August 8, 2017

November 2016

When we left toward Florida in the fall of ’16 the engine had just been mounted.  The weather was getting cold.  I was OK with the heated hangar but I would be batching it if I didn’t follow Dolly South.  Besides, all I had to do was hookup a few hoses and wires.

Hah!! Little did I know.

May 2017

May was all firewall forward work.  It included:

  • Installing the oil filler neck
  • Installing NGK BR8ES 3961 spark plugs gapped to 0.31”
  • Installing the exhaust pipes lubed with Mouse Milk
  • Installing the cabin heat muff on the #1 cylinder exhaust pipe
  • Installing vibration dampers on the exhaust stacks
  • Mounting the throttle servo body to the engine
  • Fabricating mounts and installing the throttle, mixture and other controls required drilling the firewall and making up cable fittings and linkages to the engine
  • Installing fuel lines from the engine pump to the fuel servo, and on to the fuel divider
  • Installing an overflow line from the engine fuel pump
  • Installing a multi-pressure manifold on the firewall
  • Drilling exhaust stacks and installing four Exhaust Gas Temperature sensors
  • Installing fire sleeve in several places
  • Installing four Cylinder Head Temperature sensors
  • Installing a Red Cube fuel flow sensor in the fuel servo to fuel divider line
  • Installing SCAT tubing from the heat muff to the firewall heater box

    Heater Muff, SCAT tubing, and fuel servo with Red Cube fuel flow sensor under fire sleeve
Pressure Manifold on upper left firewall







  • Installing fuel, oil and manifold pressure lines and sensors
  • Installing a voltage regulator for the backup alternator
  • Forming and installing the crankcase breather tube with “whistle slot”
  • Threading and lacing the wire bundle going to the Garmin GE24 engine sensor box
  • Routing the lower spark plug leads from PMags to cylinders.

    Lower ignition wires installed

May was a busy month of 5-8 hour days in the hangar.

June 2017

I took June 1st off to do EAA Chapter 77 treasury work.  After that the month included:

  • Mounting the primary alternator and wiring the field and ground lines back through the firewall

    ANL Fuses and shunts
  • Fabricating buss bars, mounting ANL fuse blocks on the lower right firewall and connecting shunts to the Garmin GE24 amperage sensor inputs.
  • Installing an alternator fail light for the main alternator.
  • Cutting and fitting nine high amperage cables for the alternators, battery and starter.
  • Installing IN5407 diode spark suppression jumpers for the Master and Starter solenoid coils.
  • Installing a starter “kill switch” hidden below the instrument panel
  • Drilling a 1″ dia. hole in the rear wing spar IAW Van’s instructions to pass the magnetometer plug
  • Lacing spark plug wires with wire ties to keep the wires separated
  • Testing electrical system components including a starter switch green light and annunciator panel
    Green Starter Switch Light turns off when engine runs.

    Shelf for Terminal Block
  • Fabricating a small shelf for Mounting a terminal strip under the PAX seat.  The lighting control switches were the first connections to these terminals.

    Terminal Block under PAX seat




  • Running various wires from the instrument panel to junction strips below the  Pilot and PAX seats.  The pitch and roll servo cables traverse the right side vertical channel.  The Magnetometer cable is in the left side channel.  All wires were eventually bundled in corrugated flex tubes; some covered with “snake skin”.
    Left Wiring Channel

    Right Wiring Channel







Pilot Headset Socket


  • Fabricating Pilot and PAX headset socket brackets and mounting them on the sides below the instrument sub-panel.
  • Installing the Emergency Locator Transmitter  on the tunnel cover in front of the seats.  The ELT antenna was mounted on a shelf behind the PAX seat.  Lithium batteries having a 10 year life were installed in the ELT and the panel mounted alarm.  They should be replaced before July 2027.

July 2017

The daily work continued and I

  • Removed the front crankshaft expansion plug and pierced the rear plug.  Then, I installed a new front plug per Lycoming Service Bulletin No. 1435, converting the engine to fixed pitch operation.
  • Fabricated a firewall shelf for mounting the Garmin GPS antenna under the fiberglass cowl.

    GPS Antenna shelf
  • Installed the Comm Radio antenna under the plane and on the fuselage center line
  • Installed a blade antenna under the pilot seat for the Garmin GDL-39R ADSB receiver
  • Installed another blade antenna under the PAX seat for GTX23ES transponder.  RG400 coax cable was used for all antennae.

    Flywheel and crankshaft extension
  • Mounted the flywheel and a 2-1/4″ Saber Engineering crankshaft extension to the engine, torquing the combination to 50 ft-lbs with Locktite 248
  • Installed the Comm Radio, GPS Nav, PFD & MFD EFIS, and TPX in the aircraft and began testing

    Initial fitting of engine baffles
  • Fit the front, side and back baffles to the engine.
  • Dolly and I attended the week long Oshkosh EAA Airventure 2017.  There we learned of Lycoming Service Bulletin No. 632.  Our engine serial number was included in the list of ~1300 that left the factory with potentially insecure connecting rod upper bearings.

August 1 through 8, 2017

Arriving back in Michigan I ordered the tool required to do the S/B #632 inspection. It was back-ordered.  Continuing with the build, I

  • Calibrated ADHRS #1 and #2 pitch & roll servo offsets and ran many Garmin G3X post-install tests.  The left screen in the photo shows when I stumbled onto the Garmin G3X Touch Engineering Test Screen that is not normally available to the customer.

    Garmin instrument panel – testing
  • Installed pitot/AOA tubes and wires.

Then came the day we had long awaited – the plane was ready to receive its wings!