Resistance Test Tempest & Champion Aviation Spark Plugs REM38S
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- เผยแพร่เมื่อ 28 มิ.ย. 2015
- I built this simple stand to resistance check the center electrode values on some aviation spark plugs. The contact that goes into the plug is a piece of copper tubing with an insulator around it so it can't scrape the i.d. of the well and create a track of metal that could cause the plug to misfire. These plugs have not been "bomb tested" because as many experts have proven (and they don't all agree), a plug with a high resistance can pass a bomb test and still misfire. In my opinion, it stands to reason that if the resistance is high and/or the plug measures open, it will require more energy from the ignition system to fire it and that can eventually damage the ignition system as well as lead to intermittent misfires. While testing the old Champion plugs I found one that would spring up and down when I was pushing it against the copper tube. It turns out a few of the contact screws inside the barrel had backed out, one so far that it created the springing action. A couple of the plugs that were open had a resistance reading after the contact screw was tightened but they were very high. After seeing this "feature" in the Champion plugs, I opted to replace them with Tempest because, #1) they have a consistent, good resistance reading and #2) their design does away with the contact screw, the contact is fused in place in the barrel. I've read that Champion has changed their plug design and they now fuse their contact in place, like Tempest. Additional info here: blog.aopa.org/opinionleaders/2... www.qualityaircraftaccessories... www.tempestplus.com/Products/I... www.championaerospace.com/prod... Champion's spark plug maintenance video that addresses Tempest's statements www.championaerospace.com/supp...
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I had a similar situation with spark plug issues. I had frequent bad run ups and would "burn" off the plugs before they would run smooth. The Champion plugs I was using looked good, but when I found information suggesting an ohm check several were found well outside the ohm range. Replaced with Tempest plugs. 4 years later, no bad run ups and ohm checks are all still well in range. Ohm checks and Tempest plugs from now on!
Any good ohm meter can do the job or Tempest has go/no go ohm check tool.
great video. i am troublshooting a plaguing problem with a helicopter engine. checked mags(had them both repaired), new carb, triple checked timing, valve clearances, compression checks etc. checking the plugs as a final troubleshooting and remembered about plug resistance and looked at your video. great stuff! thanks for sharing.
Glad it helped you. Something I've experienced with fixed wing Lycomings, you can get a random roughness if the exhaust valve guide clearance is getting to the limit. The 388C wobble test is definitely worth doing. Fly safe and thanks for watching.
Thanks for posting this video. I am about to enter A & P school, and was wondering about Aviation plugs vs. Automotive plugs. I have not researched what the FAA may say about it in maintenance logs or, Lycoming / Continental engine maintenance with their engines. I know I wouldn't want the engine to quit on me during a flight so I wouldn't want to compromise the ignition system either. I would like to see how you made your plug tester in another video.
While you performed a test of the plugs "after use" (and it's very helpful info) . . it would be interesting to see a like-test, for example, across 30 plugs of each manufacturer "out of the box". Each manufacturer will state (I'm guessing) they test every plug before shipment (but being in manufacturing for a while) I'm willing to bet they temper that statement with QCing (testing) a more modest sampling (say one manufacturer perhaps tests 1-in-10 plugs and another may test 1-in-30). A test of perhaps 30 plugs of each "out of the box" would be interesting (you'd obviously have to get a retail distributor to agree to work with you on that - - i.e., agree to put them back in the box and shelf after testing or send any "discovered bad ones" back to the manufacturer. But it might make a good name for themselves if they state on their window they do such "consumer retail testing" on behalf of their retail customers. Just a thought. (I'd certainly be more apt to buy from them if I knew they did such quality tests as a retail distributor from time to time)
You may want to review the difference between ohms, kilo ohms, and Mega ohms.
I noticed that also. The one champion read .364 so thought it meant 364 ohms when the ""M was on...... .364 meg ohms or 364,000 ohms. The best way to do this test is to turn off auto-ranging. Tempest calls out anything > 5000 ohms as a fail.
P.S. Nice test setup
flat out scary
Hey thanks for this. What material is your isolator around your soft copper? TIA!
It's a piece of 1/4 copper tubing with a sleeve from a plastic cap around it for an insulator.
What size tubing did you use?
Pat Ricciardo if I remember correctly, 3/8" soft copper tubing. Thanks for watching!
So you are slinging away a $100 plug on the basis of a reading given by a cheap multimeter that probably uses a pair of AA batteries for it's operating voltage? Glad you're not doing my Annual! Suggest you go back to A&P school and turn in your IA.
The data be damned! I've got Fluke, Simpson, this and other meters, they all measure the same. Lucky for me, we have an ISO certified calibration lab at work so I can have all of my tools checked, verify they are correct and have them certified. Ohms are ohms regardless of how the meter is powered. As you saw, several of the Champions had open readings. How long is it going to be until the ones that had continuity develop an open? Several of the contact screws in the Champions were loose and all had rings burned into them from the spring on the end of the lead. There were several signs that pointed to the IGNITION SYSTEM was operating near or at its maximum voltage, putting unnecessary stress on everything. Thats when the research started. Once you see a spec do you ignore it? In the end, the only choice for me was to spend the money and provide my passengers and I the safest plane I could.
champions suck! lol there is a reason they changed the design and didn't tell anyone. Go look at a tempest inners then look at a new champion plug and an old one. its pretty clear. new champions almost identical to the tempest. Can you fly the old champions and have nothing happen sure( in my bonanza now) but they will be out soon even with only 250 HR on them.
@@snaproll94e Shouldn't the ignition system always operate at it's maximum voltage?
David Carter, no, it ideally should have a reserve of voltage so it can fire a plug or cylinder that is operating at less than ideal conditions, i.e. a plug that is fouled, oil soaked, cylinder that is excessively lean or rich. As an aircraft goes up in altitude there is less ambient air pressure. With less air pressure the spark in the distributor cap is more prone to cross firing. If the ignition system is operating efficiently and requiring less voltage, there is less chance of cross firing and a spark leaking out of a worn lead or something similar. It's not often discussed but higher ambient air pressure actually helps to corral (for lack of a better term) the ignition energy. To cure high altitude misfires on piston engine planes they pressurized the inside of the magnetos, this forced the spark to jump from the rotor to the terminal in line with it and not to jump elsewhere in the cap as it seeker the least path of resistance to ground. You can google the subject and learn more. Thanks for watching.
@@snaproll94e Not to mention, you had consistent readings across all the Tempest (plus you had fairly consistent readings across the 1,200 hour Champions) . . so your data was not 'bad' as the poster suggested. Seems to me he's the one that is obviating the obvious.