Ignition timing

Picked up 10 spark plugs today. They are a Champion D16.

I also started working on the magneto’s. In the past it just all looked complicated, with timing, and so many cog wheels etc. But now I understand it all, it looks pretty straight forward.

The engine needs to be timed to fire at 30 deg ahead of centre. So to do that, the engine is turned in the direction of rotation until the #1 piston is coming up on compression and is 30 deg ahead of top dead centre. So that is where I want ignition.

Now I need to set the magneto right. This magneto has a rotor with the magnet and a small gear. The distributor has a large gear that is driven by the small rotor gear.

On the same rotor, is a cog that drives the contacter. So first I position the rotor so the contacter is about to open. Then I mount the distributor with its large gear in the position where the #1 ignition lead is “in contact” with the high voltage coil. There are two marks on this distributor that show me exactly where that is, so that’s easy. And yes when the distributor blocks are in place I can now see that the distributor is exactly in the right place.

That’s the magneto timing set really. Now turning in the direction of rotation, the contacter opens when the distributor is exactly over the #1 contact.

So that’s done, all I need to do now is mount the magneto’s on the engine. There I can “disconnect” the magneto from the engine with 3 nuts, so I can move the magneto so it’s firing exactly at 30deg ahead of centre , but I will do that in the next few day’s.

Spark plugs

Got an email from Chad:


These low compression engines will tolerate any number of different plugs.

If you must have noise canceling then you should go shielded but since the mags are not set up for shielding you’ll have to ground the woven exterior of the standard modern aviation mag wire. Of course there may be some automotive wire that will do the same thing but I don’t know. You must however stay away from carbon core automotive wire – they must be wire core.

This is not to say that non shielded installations will in fact cause radio interference. You might experiment first before investing. My experience is that some do – some don’t!

So yes that’s what I wanted to hear so that’s good. This means I am going to find some local available spark plugs, and wire them to the magneto’s

Control panel

Made a temporarily control panel with all instruments for the engine. Voltmeter to make sure battery is OK, as other instruments will be low if the battery is running out. Others are oil pressure, oil temperature and tacho. I have wired up everything except for the tacho as I need to do a bit more work for that.

The two switches are for controlling the two magneto’s, the ignition system 🙂


As you can see above and below, yesterday I did all 10 push rods for controlling the 5 exhaust and 5 intake valves. The tappet clearance is set to 0.035″, just under 1mm.

Also as you can see below, the oil tank is there now. I am using the original one for now, but will be using another one on the Bleriot.


And the heat exchanger to de-ice the carburetor. Hot exhaust gas goes through it to preheat the carburetor and the air fuel mixture, stopping it from freezing up.



And last thing today, the carburetor 🙂
Not much left now (oil connections to tank, magneto’s, spark plugs, ignition leads and a control line to the fuel control needle on the carburetor). Later I am going to make a ring exhaust, properly connecting the exhaust of all 5 cylinders. But for now not worried about that.


Champion C26

Started spending some time looking at this spark plug. By using the good all “Google” I found that this was a Champion C26. Some history:

1920s – 1930s :

  • Champion began development of spark plugs specifically for aviation industry.
  • Champion Aero-1 plugs sparked world’s speed record (318 mph) and world’s altitude record (38,793).
  • Champion spark plugs helped power Aeronca Dowager, first successful U.S. light plane.
  • Created Aero RA, a low-profile spark plug with radio dome shield.
  • Expanded facilities for ceramic research.
  • Pioneered the C-26 spark plug.
  • Developed industry’s first aluminum oxide insulator.


So I am looking for a replacement of this spark plug. Trying to understand what parameters are important for finding the right replacement. And then there are the ignition leads. Do I use just plain old copper, compression leads or shielded leads……


Primer valve

The carburetor:

There is a primer valve that supplies fuel into the engine. First thing you do when starting, is close the throttle and spin the prop around a few times with the priming valve open. This will suck fuel into the carburetor.

Chad my propeller manufacturer told me he had lots of problems with his Velie (like my engine) as this primer valve was leaking when the engine was running.
So what I did here is, I left that valve closed and sprayed fuel into the hole you see below, just above the throttle flap, and waited.

Nothing happened, the fuel didn’t leak down through the valve, so it must sealing alright 🙂


3 Of the 5 hoses

Here are 3 of the 5 hoses. The 3 here are oil hoses. 2 That you don’t see here are a hose for the oil pressure sensor as it shouldn’t be mounted on the engine, and the last one, the 5th one, the fuel hose. What you are looking at is the bottom of the engine.


At the bottom of the image you see the fuel pump, with two sections.

  • The bottom section is the high pressure pump, with the brass inlet from the oil tank on the right. To the left is the pressure relief valve that can be adjusted. Left from that is the high pressure oil hose going into the engine. That oil under pressure (80 – 100 pounds/square inch) gets pumped into the crank shaft. While flying that pressure is not allowed to drop below 60 lbs.
  • The hose you see in the middle is a drain, that drains oil from the gear case into the oil sump, the small green unit at the top of the image, with fins on the outside for cooling the oil.
  • The bottom of the oil-sump goes through the brass fitting that has a “sif” in it, back through the third hose (the right one) to the second (top) section of the oil pump, the scavenger pump. Before it gets into the pump, a temperature sensor measures the oil temperature. The brass fitting on the left side of the scavenger pump returns the oil back to the oil tank.

The “sif” is not original. I want to make sure I can inspect what goes through the oil system after a flight, by simply opening this “sif”. This also protects the oil pump in case something goes wrong in the engine. The “sif” can also be removed completely if that’s required for some reason………

Cogwheel onto the oil pump

Put the cogwheel back onto the oil pump. Used a 4mm roll pin to lock the cogwheel on the axle driving the pump. As the original pin was thinner, I had to use a drill bit to make the hole a bit bigger. Ended up using a Titanium Carbide drill bit. The steel of the cogwheel was so hard. Good I suppose !

After the pin was in, I widened up the two ends so it can’t go anywhere.

Also started to attach the steel braided hoses with a black outside. There are 3 short ones, some very short, which makes it just a bit harder but not impossible. And then there is one long one for the fuel and a thinner one for the oil pressure sensor. Looking good !!!