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More little things.

4.5 hours.

I brought the newly painted cowl back to the airport and yes, it looks way more badass in olive drab than pink.  I also took care of some things that have been bothering me for a while but never got around to doing.   I re-did the cotter pin on the prop pitch control on the quadrant because I’d forgotten to put a washer between the pin and the lever.   This is now fixed.   The left control stick now has a cotter pin as well.

After that it was the endless tedium of safety-wiring a bunch of hose clamps and other fittings.   I hate safety wire, but I can’t argue the fact that it can keep you from having a really interesting day.      I think I got most everything on the right side.   I’ll do the left side next time.

I also need to make an appointment with Randy to get my avionics calibrated, but I’ll have to wait until Monday.

Idle fixed.

5.5 hours.


I don’t have time for a lot of jibber-jabber, so I’ll make this short and sweet:

I installed the new idle linkage bearing and spent a bit of time dialing in the idle.   I got it to idle smoothly at 750 RPM with a solid transition to power on throttle advance.   CHT’s sitting there uncowled don’t get past 245, which is good.   We had a really strong wind today, so it was a good day for engine testing, but a crap day for flying.  Nobody was out there, so I was left to my own devices.  The idle fix took about two hours, so then I went for a drive.   I taxied down to the west end of the runway, then came back.   20+ knot winds variable from 070 to 085 make for some fast footwork on the pedals.

After that was done, I set about making the fire extinguisher mount.   I ended up putting it on the fuel pump cover, in easy reach of both pilot and copilot.  Of course, if the fuel pump’s on fire, getting the the extinguisher is going to be interesting.   I had to reinforce the fuel pump cover with some .032 so the bracket could be safely bolted on, but it seems to work.


Red Goo.

5 hours.

A shortish day, after Thanksgiving weekend.  But decent.   I got the pax side restraint system involved in addition to the pilot side crotch strap or “anti-submarine” restraint, as it’s called.  That took longer than I thought because of the number of times I had to hop in and out of the plane to find washers and other hardware and tools.

But now they’re both in.  This unflattering photo is just to show that both seat belts are hooked up.


So I went on to the red goo.   I’ve been putting this off, because of my usual aversion to non-solids, but it was finally time to RTV the baffles.   Squeezing a tube of red RTV into all the places it has to go is really hard on the hand muscles, especially when you have to get the nozzle into nooks and crannies now blocked by FWF equipment.

IMG_1685So I’m not the best RTV’er in the world, but I think the bases are more or less covered – a bead running along the baffle meterial, and anywhere light gets between the baffle and the engine.   OK, maybe not everywhere, but everywhere I could get the stuff in there.

IMG_1686Oops.  Didn’t get around the right magneto blast tube.  I’ll have to get that later.

But I was sure to get RTV into all the gaps between baffle and oil cooler, because that’s kind of important, and as for other leaks, we’ll have to see what happens to CHT’s in flight.

Odds, ends, and annoyances.

6 hours.

Last weekend I had to work to deliver a product launch, so no airplane.   This weekend, I had a list, and I knocked out a bunch of stuff on it.  To sum up:

  • Tensioned and safety-wired alternator bracket
  • Removed protective plastic from aft canopy and removed tape residue
  • Relabeled mag switches and made “OFF” labels for everything else
  • Reconfigured quadrant for extra travel on governor
  • Added a wider heat shield to protect the throttle cable
  • changed out a too-short bolt on the purge valve cable bracket.

Apparently the way you do alternator belt tension is by increasing belt tension until it takes 12 ft/lbs of torque on the alternator nut to slip the belt.   That’s it.   That also gives you the 1/4″ deflection (on a new belt) called out by the usual procedure.   This is important, because a slipping belt can cause over/under voltage problems.  I did that, and safety-wired the bracket tension bolts together, like so:

Alt bracket saftey wire

Alternator bracket Safety wiring


When I put the aft canopy in all those many moons ago, I left the protective plastic on it, because why not?  Why subject the vulnerable plexiglas to my fumbling ministrations while I’m climbing in and out of the tailcone to adjust one thing or another, swinging tools and wires about?   Because once the canopy is attached, it’s difficult if not impossible to get all the plastic out from between the roll bar support and the canopy.   I had to put a space heater in the cockpit and run it for a while, until it was a balmy 75 degrees and the plexi and surrounding aluminum were warm to the touch.  I took out all the fasteners and removed the aft canopy section, which I put on the bench, then removed the rest of the protective plastic and cleaned off all the tape residue I couldn’t get to before.  100% better.

Protective plastic and tape residue gone

Protective plastic and tape residue gone


The magneto switches on the panel were cryptically labeled “MAG 1” and “MAG 2.”   I don’t know why I thought this was a good idea, and it broke with common practices in aircraft UI/UX design.   I relabeled them “L MAG” and “R MAG” because that made the most sense, and that’s how everyone else does it.   While I was in a labeling mood, I made about a dozen or so “OFF” labels to describe the down position of most of my toggle switches.   The double-throw switches like flaps up/down already had good labels in both directions, but there wasn’t anything labeled “OFF” anywhere.  The switch pointing toward the function described seems obvious to me, but apparently it isn’t to whoever wrote that reg at the FAA, so now everything is labeled according to the AC’s.


Like I said, there were odds, ends and annoyances.   Firewall forward, there was the matter of a heat shield, a too-short bolt, and the prop governor travel.

Heat shield on throttle cable

Heat shield on throttle cable

I did have a shield in place at this spot, but I remembered I had an extra double-wide one, so I put that one on in its place.  On the topside of the engine, I changed out the bolt holding the purge valve cable.   It was a temporary thing when I did it, and it didn’t have the required number of threads showing to meet spec, and since it’s pretty important that the purge valve remain closed in flight, it’s also important that everything connected to it is not half-assed.  This is what the proper bolt length looks like:

Purge valve cable bracket

Purge valve cable bracket

As to the prop governor, if you’ll recall from last time, the prop didn’t cycle at the low end of the throw.  The quadrant was only moving the lever arm about halfway through its arc of travel.   The simple fix to that was to drill a #12 hole about 5/8″ up the quadrant lever from the original one and voila, I get me 75-80% travel instead of 50%.   That story ended with a quick runup to 1800rpm and getting the prop to cycle, so that’s good enough for now.   Whether or not I have the rpm set right due to the arm position relative to the governor shaft is another story, and it will be resolved on either a full power run or first flight.  Even so, the engine is more responsive, now that it’s firing on all the plugs, which are now more or less synchronized in their ignition, so that’s a plus as well.

What was really awesome about this weekend was that for the most part, it was forward motion, not playing catch-up.  New things got done and good fixes were made, rather than unsuccessful stabs at a persistent and difficult problem.   There’s still a bunch of stuff to do to get ready for first flight, but I think if I can keep up the pace, I’ll be on track to fly it in early 2014.


Magneto repaired, on to restraint system

6.5 hours.

Within minutes of arriving at the airport this morning, I replaced the distributor block assembly and the distributor gear in my right magneto, the one that’s been sitting on the bench for a couple of weeks.  It was a complete non-event.  I got the new distributor block out of the box, put the timing pin in it, installed the new distributor gear, lined it up, and screwed it down.   Done.

I put it back on the engine, did the buzzbox test again, and got them both lined up dead nuts at 20 degrees BTDC.  Of course, the proof is in the pudding.   I wheeled it outside and fired it up.   It ran just fine, of course.  Equal rpm drop on both mags, and nice smooth running.

The other little issue I need to work on is the prop governor.   I set the arm to what it was when I got it, based on a previous photo.   In that position, it doesn’t cycle the prop all the way to coarse pitch.   Makes sense, the arm can only move about half way, given the cable end’s position on the quadrant.   I’m going to have to drill a hole  another 3/4″ up on the lever arm to get that extra throw.

After the quick runup, I shut everything down and pulled it back into the hangar to put back all the stuff I’d discombobulated during my clownish magneto debugging.   Wires got wrapped, nuts and screws got torqued, and everything went back to being a proper firewall-forward configuration.   This took a bit of time, but it really wasn’t too bad.

One of my goals for today was to work on the seat belts.   Seat belts are pretty important.  They keep you from becoming one with the instrument panel in the event of an impact incident.   Mine are some nice gray Crow 5-point harnesses with a cam-lock release.   Like so:

Obviously, some adjustments need to be made, but I think they’ll work pretty well with the seats.    The bolt holes in the attach ends are pretty big, so to get them to work with AN4 bolts, you have to fill them with something.   AN960-416 washers work pretty well, but they need some adjustment.   For them to fit into the attach holes, it’s necessary to shave off some of the outer edge material.   This is best done by putting a bunch of them on a bolt, chucking the bolt into a drill press, and running a file along them as they spin.   Then you can press-fit them into the seat belt attach holes (if they don’t just fit), and everything’s cool.   The only thing missing here is the crotch strap,, which I have to take the floor pan out to install.

Magneto Mystery Solved.

7 hours.

So remember when I was trying to debug a nasty popping, backfiring, horrible magneto?  Yeah, like it was yesterday.   Matter of fact, it was yesterday.  And today.  Every engine test since first start has been a mess and the reasons are plentiful, going back to when David and I first tried to get it running a while ago. This has been going on for 3 weekends now.

First, I modified Bob Nuckolls’s electrical system diagram to include a pushbutton starter switch in addition to the spring-loaded (ON/OFF/(MOMENTARY ON) switch.  Turns out you can’t have both.  What wound up happening here is that when the spring-loaded switch was set back to center ON, it was grounding out the one magneto capable of running the engine.  I’ll get to that in a second.  In addition to that, we were never sure which wire went to which magneto, because those two bits of shielded cable never got labeled.   Lesson #1.  We did eventually test that and got the wires running to the correct mags.  We think.

If I wanted to keep my stick pushbutton start, the  On/OFF/On switches would have to go and be replaced with dual-pole ON/ON switches, which would allow me to disengage the start circuit as well as ground the mags, making them cold and safe.   I replaced those switches, and maybe here, maybe the step before, the wires got switched again and left went to right and right went to left.  The good news is that with these switches installed, the engine fired up.  Ran a little rough, but it was a damn sight better than last week.   OK, shut down right mag for RPM drop.  No drop.  Shut down left mag for RPM drop.  Bang, boom, sput, cough.

As you might expect, shutting down the “left” mag caused the engine to pop and misfire, so it was assumed that something was wrong with the right magneto.  First thing we did was switch it out for a good one, the one my hangar mate had in a plastic bag for eventual installation on his RV9.  Timed it to the engine, buzzboxed it, fired the engine up.  Same thing.   At this point it was a head-scratcher, because here we’ve just put a brand new Slick 4300 series magneto on the right side of the engine and we’re still getting popping, misfiring, the same thing.

Oh, one important detail I’ve left out of this story so far:  I don’t know how many times we pulled the magnetos and checked and rechecked the engine timing.  During this process somwhere, I the timing pin (an allen wrench or a pop rivet)  in the distributor block when we pulled the engine through to set up the engine timing.  Maybe I even did it at home before moving to the airport.  At one point, I pulled a very bent allen wrench out of the left mag and a bent pop rivet out of the right one.

I assumed that because the “left” magneto was working fine, it was the right one that was messed up, but that couldn’t be because I’ve just replaced it with a brand stinking new one.   Matter of fact, when I opened up the mag I’d pulled out of the airplane, everything looked fine.  The distributor gears were OK, the rotor was fine, and the distributor block wasn’t cracked or anything.   I left Ron’s spare mag on there  because I had more debugging to do and I didn’t want to change back to the original mag, which may have been compromised in some way, even though none was evident.

Yesterday, I thought, hm, maybe the wire going to the magneto is shorted somewhere.   So I disconnected the terminals from the mag (and took the harness cap off to be safe) and tested them for continuity.   With the switch set to “ON” there should have been no beep from my multimeter.   I got a beep.   AHA!   There’s a short in the shielded P-Lead wire!  So what do i do then? Cut the ends off the wire to the “right” mag at the switch, thinking maybe the connection shorts intermittently because I cut the insulation of the wire and the shield’s touching it.   Still beeped.   OK, that wasn’t it.. Maybe it’s at the mag end.   Cut that off.   Strip back some cable so I can test the ends.   Still beeped.   At that point the day was pretty much over.

Last night I was falling asleep reading Book 7 of Stephen King’s Dark Tower cycle and it hit me.  What if the wires were on the wrong switches?  Left is right, right is left.  That would mean three things:  One, the “short” in the P-lead cable isn’t a short at all.   The other switch was cold, so the multimeter would have beeped no matter what, because disconnecting from the switch and still connected to the other mag, there’s enough continuity for a beep.   At the mag end, testing the wires would produce a beep because they’re going to a switch in the cold/safe position.   Two, this would also mean that I’ve been debugging the wrong magneto for the last two weekends in a row.  All my attention was focused on the wrong part of the system and it didn’t occur to me to check something as simple as wiring because I’d already gone down that rabbit hole and figured I’d verified it multiple times.   Three, I’m an idiot.  Once for leaving the timing pin in the left magneto, twice for not checking the wiring, and three times for assuming things were correct in places where they weren’t.

I hadn’t planned to go to the airport today, but I did.  I figured it would only take me a couple of hours to sort this out, so I loaded up the bike and headed to OXR.   First thing I did was pull the right magneto and check the internal parts for damage.   This was onerous.  I routed my hoses and cables so they trap the magneto in a cage with no hole big enough to let it exit.   I had to take the oil pressure sensor hose off to extract the magneto.  It always makes me nervous doing that.   All I need is for a lock washer to fall down inside the engine accessory case and I’m totally screwed.   I did manage to extract it, and got it up on the bench, where I was able to remove the back cover and the distributor block.   Guess what I found:


That right there is the rotor gear.  This spins on the shaft that opens and closes the points, making the spark.  Notice that there are two teeth missing, and several of the others are damaged.   The bottom line here is that no matter how carefully the engine timing is done, there is no way in hell this gear will drive the distributor gear in any way that will provide a spark at the right time.  To prove this out, I reassembled and installed the old right mag on the left side of the engine.   I have two impulse-coupled mags, I can do this.   I remembered to take the timing pin out, say thankya and may it do ya fine (Dark Tower, remember?).   Then, miracle of miracles happened.   The buzzbox timing process, which I am now intimately familiar with, went just like all the documentation, descriptions, and YouTube videos said it would.  Snap the impulse couplers, back off enough to get rid of gear lash, then move the prop forward to 20 degrees BTDC.  twist one mag until the light just goes on or off, depending on what it’s doing when you turn the box on.   Back the prop off again, then move it back to 20.  The light should go on right there.   Twist the other mag until the same thing happens.   The trick is to get both lights to come on at the same exact time.

With two teeth missing off the rotor gear that wasn’t ever going to happen either, so wiggling the mag back and forth on the dead spot betwene those teeth isn’t going to do squat.

But joy of joys, sing hosannah to the heavens, with two properly timed and synchronized magnetos, that engine runs smooth and strong, like a big cat purring.   Ron helped me push the ship out into the sun and I fired it up.  Rock solid, dead on.  RPM drop on both mags, just like that beat-up Cherokee I learned on.

Now I get to go back in and clean up the mess I made testing everything.  Re-wrap my wires, safety-wire the governor, everything back int its place.

More Magneto woes.

6 hours.

At this point, I’m out of ideas. I unshipped the right mag and took the rear cover off to inspect the rotor housing and gears. Even though I left a pop rivet in the timing hole and turned the prop, the distributor gear seems fine. I followed the procedure in the repair manual, and timed the distributor gear using the marks on the rotor and the gear itself, then reassembled everything and put it back on the engine. Same result, no joy on right mag. So, bad magneto, right?

Wrong. This is where it gets truly odd. Ron loaned me the new impulse coupled mag he has for his project. I timed it with the pin, put the engine at 25 BTDC and put it on. Timed it with the buzz box, and tried firing it up. Exact same result.

I now have no idea what is going on.

It’ll have to wait two weeks until I get back from training with Mike Seager in Oregon, which is in two days.


5 hours.

Today was about putting things back together and getting a handle on some of the chaos.   The first bit of good news is that the oil temperature probe works fine.  I pulled it out of the engine and hit it with a heat gun and sure enough, it gave me a reading.  So I’m not going to worry about that anymore.   I secured the wires back in their bundle and i’m calling that squawk done.

I also wasn’t real happy about the weird way I had the fuel pressure sensor set up.  The Adel clamp holding it was maybe a size bigger than it should have been, and this way seems more secure:


As I mentioned last time, I flipped the governor arm over and it seems to work just fine:


My biggest problem with doing it this way was where the injector line was going to go.   A piece of angle solved that.   Now it’s out of the way, and less likely to be heat-soaked down near the cylinder.  I still haven’t safety-wired the screws yet, or put the cotter pin in the cable attach nut, But I think this is how it’ll stay.

Last week, Owen recommended tightening up the tailwheel chains.   Van’s recommends a half an inch of slack, but if you ask ten different people how they like their tailwheel chains, and you’ll get at least five different answers. But my chains had an inch of slack, and if I took a link out, I’d have none.  But I did take a link out of each side, and while there isn’t really any dangling slack, I can move the chains up and down by about a half an inch, and I’ll tell you, based on today’s test, it taxis just fine:


That little gap in the rudder fairing is kind of annoying.   Not exactly sure what to do there, except put nutplates in there and hope for the best.

Today’s test was all about seeing how things went with the cowl on.  First, I wanted to make sure I could actually get the cowl on with the flipped-over governor bracket making the cable rise a bit more than it did before.   Turns out, I’ve got about 1/8″ of clearance between the cable and the top cowl, which is good enough.   And from what I remember, the cowl inflates a little in flight, so that 1/8″ becomes a little more.   And that’s fine.   I just don’t want to have to put a clearance wart in the cowl to accommodate the cable.


But before taking it out for another test, this adjustment had to be made to the baffle material on the lower cowl.  I had to cut it back a bit, because it was covering up about 6 square inches of air intake.   Bad.   So with this mod in place, I put the top cowl on, and pinned it down.   Then I put a few of the floor panels in, and you’d be surprised how much the plane stiffens up with the reinforcing action of the panels.   I ran it up, then shut down the left mag.  Engine died.   Started it again, repeated.   OK, right mag dead.   Grr.   Still runs fine on one though.

So I said screw it, let’s taxi it around.  The new tailwheel chain tension was much better.  Now it’s more like Mickey’s Citabria, and the ground handling is nice!  I took it to the end of the hangar row, turned right, went down the next row, turned right again, then went back to the barn.  CHT’s never got above 210.   As soon as I get this mag situation sorted out, it’s time for ground runs.

\Last time, shutting off the left Mag made a lot of popping and missing, which I attributed to timing.   This time, I’m pretty sure the timing’s right, but now shutting off the right mag shuts off the engine.  Now, it might have something to do with the fact that I left the pop-rivet I was using for a timing pin in the hole when I pulled the prop through, but I can’t say for sure.   What I do know is that before, on the right mag, I had backfiring.   Now I’ve got squat.


Magnetos timed (again) and RPM sensor fixed.

6 hours.

One of the day’s tasks was to replace the magneto gasket we tore with a new one.   This necessitated removing the right magneto, the one that was cranky about timing.   This is also the mag that has the hinky contact spring on one of the harness wires.  I figured what the hell, I’ll make sure both are timed, so I’ll pull both, put new gaskets on both, and set the timing again.   Big mistake.   Timing mags with two people sucks, as you might have gathered from an earlier post.   Doing it on your own sucks too, and then some.   Yesterday it was hot and windy at OXR, so the hangar was warm and the doors were rattling and making freakish noises every couple of minutes.

There are various sources of knowledge as to how to time mags, but the general idea is that you turn the engine over until the crankshaft is at 25 degrees before top dead center.   Then you zero the mag position by sticking a pin in the timing hole in the back of the magneto where it will sink into another timing hole on the gear inside, thus locking the thing into the position where the points are open.  Then you stick the mags back on your timed engine.

A number of factors are at work here.   There’s the impulse couplers, there’s the slop in the mags even with the timing pin inserted, there’s gear lash in the engine itself, and there’s the ambiguity of where 25 degrees BTDC actually is.   Near as I could figure out, there’s a little lump in the rotation of the mag gearshaft where the points open.   This is no great mystery.   A cam inside opens and closes the points to make a spark.  That fires the spark plugs.  This is no different from your common Briggs and Stratton-powered suburban lawnmower.

But the magnetos are buried amongst wiring, hoses, and engine mount tubes, and getting them back on can be extremely frustrating.  The mag gasket is a little wider than the magneto housing, so it’s really easy to dislodge it.   The engine gears of the mags are also wet with engine oil, so they’re slippery.   It’s also of primary, critical importance that nothing falls down the open mag hole into the accessory case.   If that happens, game over.  If that happens, you better hope whatever fell, like a nut or a washer, falls all the way through into the oil sump where it gets stuck to a magnetic plug — if you have one.  The obstacles in the way make it easier, but not by much, to insert the timing pin into the housing with the mags more or less in place, but supporting them, spinning the gear, and inserting the pin is one of the more frustrating solo tasks there are.  The trick is to get both mags installed so they’re within just a few degrees of each other, because there’s only about 70 degrees of twist available to bring them into line.    If they’re too far off, they’ll never sync up.

The next part is relatively easy, assuming the first part goes OK.   This is where the buzz box comes in. This thing has two lights on it, and you connect the leads to the P-lead connections on the mags.  When the points are closed, the lights are on.  When the points are open, the lights are off.   Or vice versa.   Can’t remember.   The point is, the status of those lights is supposed to change when the engine turns through the specified timing mark on the flywheel.   Both mags are supposed to change at the same time.    There’s actually enough wiggle room with the timing pins in the magnetos to put the timing off by a whole gear tooth.  If it’s off in opposite directions on each mag, there might not be enough range to bring them both back into line at the right point.     But eventually, I got it.   The trick is pulling the prop backwards a bit, then advancing to see the lights go.   The prop has to be pulled backwards enough so that going forwards takes out the gear lash well before the points open, otherwise the adjustments are crap.   But you don’t want to go so far back that you catch the impulse couplers again.    Maybe this isn’t the proper way to do it, but this worked for me.  Also of important note: pull the timing pin out of the magneto before cranking the engine around.   If you don’t, best case is you’ll bend your timing pin like a wet noodle.  Worst case is you damage the innards of the mag.

So I got them as close as I possibly could.    Then I put the shielded ground wires back on.   For safety, the shielded wires go back on the P-lead and ground before the distributor caps go on, because until they’re on and grounded, the mag is hot, and if a spark is triggered, it could swing the prop and really ruin your day, especially if you or your stuff is in the prop arc.   Imagine that.  The prop kicks and sends a blade into the tank of your air compressor or a nearby tool cart.   Prop strike!   Have fun tearing down that engine, sunshine.

By the time this process was over, I was already well past my scheduled time to head back to Los Angeles.   But if you’ll remember, this exercise was only part of the day’s activities.   The other things I needed to attend to were the RPM sensor and the oil temperature probe.   Earlier in the week, Matt at MGL responded to my email and said I needed to remove the ballast jumper on the RDAC and that I could delete the resistor between 12v power and sensor signal.   I pulled the ballast jumper, then proceeded to push the ship out into the wind for a quick test.    Ron and Melody helped me push out and get pointed into the Santa Ana wind.   With the wheels chocked, I fired it up, once again.


It lit right up, after Owen reminded me that I needed to run my boost pump for a second to get some fuel pressure on startup.   It ran strong and smooth, and I had an RPM reading this time, but like a monkey, I forgot to test each mag individually.  But here’s another ground run video:

This time, however, was another milestone.   We pulled the chocks and I actually taxied down to the end of the hangar row, then back.   At that point, my EGT’s were starting to get a little high, so I thought I’d quit while I was ahead.  We pushed it back into the barn and I went home.

Equal parts forward and back.

6 hours.

One of these days, I’ll move forward without moving backwards.  Today I had to dismount the EFIS in preparation for taking it to MGL Avionics.   Apparently the OAT module is fried.  I tried it with a new probe last week, no dice.   Maybe, if I’m lucky, I’ll be able to drop it off tomorrow on my lunch hour.   Other than that annoyance, I got the tailwheel hardware primed, something I should have done long ago, and I got my spark plugs torqued in.   But now, for some mysterious reason, the tailwheel steering chains don’t reach their mounting points on the rudder anymore.   It’s possible I had the steering link on upside down/backwards, which would have accounted for the missing 3/4″ of chain necessary to bridge the gap between what I need and what I’ve got.   Looks like I’ll be ordering another set of tailwheel chains.  Grumble.

Anyway, once I get my EFIS back from the shop, it’ll be time to prepare the engine for first start.

On another note, I’m progressing nicely in my tailwheel training.   We flew from Torrance to Hawthorne, where I did 8 landings, unassisted.   Apparently I CAN land a Citabria in 3-point attitude.   At least when the wind is coming at me and I set up the approach right.