Do aircraft cylinder heads already have CHT ports?

Discussion in 'Maintenance Bay' started by AggieMike88, May 14, 2018.

  1. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    EdFred's story about the installation of his engine monitor and our club's recent installation of a JPI-830 brought this question to mind.

    Are aircraft cylinder heads manufactured with a port for the CHT probe already there? Or is this something that the shop drills/taps as part of the monitor install?
     
  2. Checkout_my_Six

    Checkout_my_Six Final Approach

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    yes...the threaded port is there.;)
     
  3. mondtster

    mondtster Pattern Altitude

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    Some are, and some aren't.
     
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  4. denverpilot

    denverpilot Taxi to Parking

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    This. And some folks use the ring style sensors that go around spark plugs which have their pluses and minuses.
     
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  5. bnt83

    bnt83 Final Approach

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    Indeed. I think almost all do now except the small bore engines. I know the Continental O-200/300 was one that needed a certain aftermarket cylinder installed to get them.
     
  6. Checkout_my_Six

    Checkout_my_Six Final Approach

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    if they don't....spark plug ring thermocouples can be used.

    [​IMG]
     
  7. bnt83

    bnt83 Final Approach

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    Some have them and have a tanis heater in them so to install and engine monitor you would likely want to replace then tanis thing with something else $$$.
     
  8. bnt83

    bnt83 Final Approach

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    I would do just about anything to aviod using them, they suck that bad.
     
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  9. Checkout_my_Six

    Checkout_my_Six Final Approach

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    Meh....yeah, they work. I have one outta six that is one of those.
     
  10. mondtster

    mondtster Pattern Altitude

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    Tanis now has cylinder head heating elements that also contain a thermocouple to allow CHT measurements. But they’re expensive.

    This is one of the reasons I like the Reiff heaters better.
     
  11. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    What exactly is it about the spark plug ring sensors that sucks?
     
  12. Tom-D

    Tom-D Taxi to Parking

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    short useful life?
     
  13. wsuffa

    wsuffa Touchdown! Greaser!

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    I had shorter life from the EGT sensors. YMMV.
     
  14. Stan Cooper

    Stan Cooper Line Up and Wait

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    The O-200/O-300 ECi Cerminil Titan cylinders have a CHT probe boss.

    [​IMG]
     
  15. denverpilot

    denverpilot Taxi to Parking

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    They break. People break them changing plugs too. They have a tendency toward shorter life. They have a tendency to always show a slightly different temp than the ones mounted in the proper holes for such a thing... (which will drive the more anal retentive owners insane...)...

    On a lot of aircraft, the electronic can’t replace the factory CHT for... paperwork reasons... so the owner has to use a spark plug sensor on that cylinder to keep the factory one in place and happy.
     
  16. Checkout_my_Six

    Checkout_my_Six Final Approach

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    you do know the temp at the plug is hotter....so it should be different than the bayonet location.
     
  17. denverpilot

    denverpilot Taxi to Parking

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    Yup. So if you have one that has to stay on the plug the pretty little graphs on the electronic engine monitor never quite line up and it bothers some people.

    Personally I think many people go from basic instruments to one of the monitors and drive themselves batty with all their new data. The times the engine monitor comes in handy and wonderful are much larger swings than the newfound precision of the instrument tends to show and freaks people waaaaaaay out.
     
  18. Radar Contact

    Radar Contact Cleared for Takeoff

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    I have all the gasket probes on mine. I have Tannis heaters on both engines. After talking with Insight, the only issue is they may show slightly hotter than the bayonets. Since all mine are the same, I'm okay with that. I still use 380 as a goal knowing that if anything I'm slightly cooler. Insight told me if they are handled appropriately during spark plug removal/installation they should have the same life. That's a big if but I do my own plugs with the exception of annual.

    Would I rather have bayonets, sure. Considering it doesn't make sense to remove 2 perfect condition Tannis units I'm happy with them so far.

    I absolutely love my engine monitor. My last 1500 hours has been almost exclusively without one. In the year that I've had it, I found a few spark plug issues (replaced them all) and a fuel injector issue (resolved by cleaning). Now I can run my engines more precisely where I want to be LOP or ROP. Being able to download the data after each flight allows me to potentially catch a exhaust valve issue (combine with regular bore-scoping) and monitor more closely other trends (fuel flows, electrical, etc). I don't spend time staring at it while flying but I could see how someone new to it could drive themselves batty if they don't understand the best way to use it. The other huge improvement for me is having the fuel totalizer with my monitor. After getting the K-factor fine tuned I love knowing exactly how much fuel I've burned and have left. With 4 tanks and 163 gallons, I don't have the ability to just fill it to the tabs. I'll routinely fly several shorter flights and only refilling what's needed for the next flight.
     
  19. hindsight2020

    hindsight2020 En-Route

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    i thought about replacing the inop egt gauge with an engine monitor...but then i remembered im flying a lyco 360, so i moved on with my life.:cool:

    Between that and ERAUs antics crapping on everybody, statistically i should be dead by now. i guess my perception is my reality after all.

    #flyingblind #ignoranceisbliss

    joke aside, if i flew a tio/tsio i def want digital backups. single probes would be fine, but the amount of heat and the poor cooling these engines were installed as, id want to know what the hell is going on in front of me in ways i certainly dont worry about when flying NA.
     
  20. Stan Cooper

    Stan Cooper Line Up and Wait

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  21. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    I'll tell you what, when you have 9 cylinders (18 spark plugs), a JPI is pretty helpful in tracking down which cylinder has the bad plug.
     
  22. Radar Contact

    Radar Contact Cleared for Takeoff

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    I can imagine. I've got 12 cylinders and 24 plugs all be it on 2 separate engines. I'd still like to have one if I had one four banger though. :)