TOPIC:

I too will be following along with your experiment here. I love the spark plug testing box to test under pressure. If it will spark @ 10 bar without fuel, it will spark at 10 bar with fuel since ionization will be more readily achieved with the fuel present. Your test box reminds me of the old Champion spark plug cleaner/tester of the 1960-1970 era..
Keep up the great work.
KB

Hi Kawboy, pressure box is needed because air resistance is growing as pressure increases and yes with no hydrocarbons from fuel is even more difficult to make spark jump but that's the perfect condition for testing. It was proper interesting project and the outcome is great in my opinion, nice learning curve plus working ignition and something to share with the forum members. The pressure testing was as follows: at 1 Bar nothing happens but from 6 Bar upwards it starts to be more difficult to achieve proper ionization and beyond eight it started to be a challenge to create the spark if plug was not clean or something. At around ten Bar things got tricky i could see the corona from high voltage on the ceramic part of the plug just above the metal hex part when firing both spark plugs under pressure but there is a danger of shooting the ignition coil while doing this. I did . Thanks for joining in.
Edit: also at higher Rpm's things are more difficult due to residual energy in the coil, as you know its a inductive load in the system so i had to find and much some new coils.



Here spark plug electrode visible, in few days in ionized air under pressure they just rot completely.



Thats how resistance of the air affects the discharge process. Look at the gap on spark plug and the one between where the cable is attached to and metal part of the other plug.



And here for the fun part the HV corona over the ceramic. I could not take the picture with mobile phone from close to it due to interference, but with coolpix camera it was ok.
Greetings.

Just to add to the conversation, here's a pic of the gauge on the Champion tester. The outer ring rotates to the spark plug gap then the air supply was adjustable. You set the ring, then applied the spark, then added the air to the point where the spark no longer exists, then read the gauge to see if the spark plugs were acceptable or needed to be changed out.
Also, the chamber had a mirror in it so you could look straight down the end of the plug and see if the spark was shorting out down around the base of the ceramic insulator which typically happened with oil soaked plugs. You can just see the mirror in the port to the right of the gauge in the pic.

You can see that the "set sparkplug gap" arrow is almost 180 degrees apart from the beginning of the "good" portion on the gauge, so plugs that fired with the ignition system of the tester at 110 psi were considered good.

it would be awesome to have an ignition system that fired plugs at 10 bar (147psi) without fuel but then all kinds of insulation issues could come up. Food for thought.

Daro: AMAZING !

Here spark plug electrode visible, in few days in ionized air under pressure they just rot completely.

Never thought about this before, and it makes sense! Perhaps because here I ride almost year round with no need to winterize my bikes?
When winterizing a good practice is to remove the spark plugs and squirt a little oil in the cylinders. Automatically this depressurizes the chambers, and this is confirms to be a good thing!

0n another note - fantastic investigative and fabrication work Daro! Thank you.

Hi there,
I did this kind of project couple of years ago with great results.