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My DA170

Discussion in 'Desert Aircraft' started by jamesrxx951, Oct 5, 2014.

   
  1. jamesrxx951

    jamesrxx951 100cc

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    Well since the wife and I are getting ready to finish our house to put on the market flying season for me is over. Part of my yearly inspection on my engines is removing the jugs to check the cylinders, pistons, bearings, etc. Just to make sure everything is good. My DA170 was purchased new in 09 and I bought it from that guy in 2010. He claimed low run time but who really knows. However there was some scratching in the piston and cylinder between the exhaust port divider. But it did not seem to bad and the engine ran good. 2 years ago when it was at DA they did take it apart for an issue I was having and they never said anything about it either.  I have always run Stihl HP Ultra roughly 40:1 for 300 or so flights at this time. The engine almost looks brand new inside and the cylinder and piston scoring has not changed. That carbon build up on the pistons cleaned up really easy because it was soft. Last night I decided to polish up the engine a little before I get the bearing replaced. Due to age of the engine I plan on sending the engine to DA tomorrow to have all new bearings installed and case seals. It is not needed because they feel good but I want new ones installed plus I will have them check it out to see if anything can be done to smooth it out. Maybe there is something they can do.

     

    BTW this engine has heated up to 350F a few times when I found out the plane needed better baffling. There are no signs from this overheat from a few years ago   [​IMG]

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  2. orthobird

    orthobird 150cc

    This is awesome for you to share these pictures.  SO that engine has about 300 flights, and that is the appearance of the inside using Stihl? Living testament to the power of that oil.  i have two of these motors, on two airplanes.  One of them has over 140 flights, but, it came back from DA several months back.  since then, i have put 60 flights on it.  the other motor has 50 flights and runs great!  never had a problem with that one. the one that has more flights, since coming back from DA, it is running like a TIMEX!! just excellent.  Maybe better would be to compare it to a ROLEX, except my Rolex that i have had for over 15 years, has its own problems.  LOL!!

     

    How many flights would you say you put in a season?

    also, are you using stock muffs, TP, or cans?

     

    best regards and thanks for sharing this.
     
  3. jamesrxx951

    jamesrxx951 100cc

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    I had this engine for 4 years. The majority of the flights were put on in 2011 and 2012. At the end of each season I removed the jugs for inspections only. Nothing cleaned up or changed. Just new gaskets. 2013 it was put in a new airframe but not flown very much. 2014 I pretty much flew it for the past few months only at that was about 70 flights. I do not know how much it was used from the previous owner but the cylinder and piston scoring was from the previous owner. But as you can see in the pics the rings do not even allow any blow by. So they are sealing very well. This engine has seen 350F on several occasions while I was trying to get the right baffling. It now runs just under 300F most of the time with a few instances of just slightly over like 305F. But that is on hard up line with a high load prop.
     
  4. orthobird

    orthobird 150cc

    James, are using an onboard telemetry sensor for the cylinder head temp, and if so, where do you have the sensor located.  if i have asked you this before, please forgive me.
     
  5. jamesrxx951

    jamesrxx951 100cc

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    I started with a venom temp monitor that recorded minimum and peak temps. This year I upgraded to the new JR XG11 with telemetry. I purchased the temp monitor that is rated for 450F I believe. It is the higher temp version. You can see in the pic both my JR monitor (screwed to the head) and the Venom on the cylinder. [​IMG]

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  6. orthobird

    orthobird 150cc

    ok, that looks good, either way, looks like you have the sensors in the back or should i say, in the shadow of the prop-wash and in the highest area, where it would be the "hottest" temp.  

    yep, so temps, when measured how you have it, will appear "higher" temps, as compared to others who have a concept of "normal range" temps based on using an IR gun.  (pointed at front of cylinder immediately after landing), which you and i both know, the temps go down on the final approach, once airplane is still in air, and we cut power down.  major cool off.  the temp upon landing is not a representation of what is happening during flight.

     

    so your temp of 300 probably is not bad.  but if this drove you to improve baffling, then this is main purpose of the telemetry.  there are many who argue against the use of it, but here is case and point, where you could monitor, you were not happy, you set a goal, and went after it, til you improved it.!!!
     
  7. jamesrxx951

    jamesrxx951 100cc

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    With the landing temps I routinely see 80-100F drop in peak temps to landing temps. So you are absolutely correct landing temps are useless unless your engine is showing 300+F on landing then you know you have a problem. Knowing engine temps I think is pretty critical to keeping an engine alive for a long time. It is cheap insurance by far. I had to come up with several different baffling systems to find one that worked well. The last version dropped temps 50F and I am perfectly happy with that. With a peak of 300F or so under heavy up lines I think im good.
     
  8. I am flying an older Futaba 8FG so no telemetry for me and I wish they still made that Venom Temp Monitor as it seemed like a great solution. 
     
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