Plug tester - worth the cost?

[smcnutt]

Not sure why but my brother suddenly seems hell bent on buying a full blown spark plug cleaner/tester. Don't know if this is the exact unit he's looking at but at least something like this.

Thoughts on the need to test plugs (we're using tempest plugs) using this pressure tester rather than the simple resistance test. He seems to think testing them under pressure would provide better feedback and be worth the cost of the tester

[Zac Weidner]

My opinion is you don't need the pressure testing that badly. I've yet to see an issue that showed up in the tester.

[Glen Geller]

Tempest spark plus ~$25 each = $200 and they last about ten years @ 100~200 hrs/year.
Spark plug tester ~$400.

Buy new spark plugs every ten years.

[Vagabondblues]

I have seen small cracks that are not visible by visual inspection looking into the ceramic insulator with a magnifying glass. Most of the cracks are started during assembly when the shell is fitted over the threaded end and crimp sealed during assembly. After many heat cycles the cracks made during assembly will grow and propagate. The only way to test the insulating qualities of the ceramic is to "BOMB" test is on a machine. https://www.championaerospace.com/as...ical/72-10.pdf

[JPerkins]

It does take more voltage to jump the gap under the pressure and turbulence that goes on in the combustion chamber than in open air. Therefore a plug that will spark in open air may not necessarily spark while underr load.
Really the tester is only handy when your having a misfire and need to chase it down.

Sent from my SM-G930V using ShortWingPipers.Org mobile app

[Zac Weidner]

Perhaps spend your money on an engine monitor. That will tell you when you have a bad plug and which one. If you have a weak or bad one, throw it away.

[Steve Pierce]

I bought a similar tester used some 20 plus years ago and can't imagine life without it. From time to time I find bad plugs that were not identified any other way. There is no justification for tools, you just want them, buy them and use them.

[andya]

sometimes when I'm too busy or lazy, I send a set of plugs to the shop in Van Nuys CA that cleans, gaps and bomb tests plugs.
Only once did they find a plug that would not pass their tester. Doing that once or twice a year is a lot less $$$ than buying
a tester. I believe Zac is correct that the engine analyzer will show the bad plug and you don't have to even remove it first.

[Gilbert Pierce]

Perhaps spend your money on an engine monitor. That will tell you when you have a bad plug and which one. If you have a weak or bad one, throw it away.

I agree with Zack. Unless you running a shop.
If you only maintain your own airplane the bomb is a waste of money. Steve “appropriated” mine because I never used it.

[blueshortwing]

I found mine at a military surplus store brand new for $35 maybe 20-25 years ago. I asked the guy why it was so cheap and he said "nobody cleans car plugs anymore, they are too cheap to buy new." He didn't know it was for airplanes......(came with both 14MM and 18MM grommets.-Ross