Lycoming High Volume Oil Pump Part Numbers???

Discussion in 'Firewall Forward / Props / Fuel system' started by HomeBuilt101, Apr 14, 2019.

  1. Apr 14, 2019 #1

    HomeBuilt101

    HomeBuilt101

    HomeBuilt101

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    I thought I would start a new thread for this inspection.

    As you know I have lower than normal oil pressure on a TIO-540 and I after painstakingly eliminating all of the items on the troubleshooting list I finally removed the accessory cover and opened up the oil pump. I discovered a damaged impeller drive shaft and the 61297 impeller (see attached photo).

    First Question: What could have caused this shaft and impeller to get so worn out in only 170 hours since these parts were new when the engine was overhauled???

    Second Question: Could this this worn-out shaft have been the culprit for low oil pressure or is it just an impending failure that has not been revealed and I still have some other problem?

    Third Question: Since I have the accessory case removed what other "usual suspects" should I be inspecting?

    Forth Question: I know that since the airplane has an oil operated turbocharger that I should get a high-volume oil pump. Does anybody know what part numbers I should get and an economical source (I am OK with "experimental" parts)?

    As always Thanks for your help!
     

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  2. Apr 15, 2019 at 12:28 AM #2

    HomeBuilt101

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    Also...the oil pump assembly that I removed from the engine has cast in the cover "75277" and then someone etched in a new part number "75287-ASSY" (see picture)

    The logbook during the rebuild states a number of parts that were installed during the overhaul and the only oil pump related parts are "61297" and "61298" and those are indeed the parts that came off of this engine.
     

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  3. Apr 15, 2019 at 12:39 AM #3

    proppastie

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    Call customer service Lycoming
     
  4. Apr 15, 2019 at 1:01 AM #4

    TFF

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    It can’t hurt to call. The etched stuff is pretty common. Lycoming uses a separate pub that has the latest and greatest part numbers. They did allow the newer manuals to be accessed on the internet, but I think they still do the updated parts separate. The parts book may or may not have the up to date number.

    To be clear, overhaul means parts are within tolerance when checked. Lycoming has a wish list that they want changed during an overhaul; the legal definition per the FAA is different and less stringent. One is company recommendation; one is regulatory definition. Field overhauled to FAA and to what Lycoming wants can be different. My bet is the pump was run before.
     
  5. Apr 15, 2019 at 2:34 AM #5

    blane.c

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    Yes rebuilt, overhauled, and inspected have different meanings. Sometimes engines are inspected and if the parts are within serviceable limits put back together. Of course you wouldn't necessarily expect a part near service limits to go another 2,000hrs.
     
  6. Apr 15, 2019 at 2:46 AM #6

    blane.c

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    If you kept the oil you drained out, did you wash the oil with clean thinner and pour it through a filter? And check the inside of the oil filter to see what kind of contamination is in it too? Babbitt metal can be bad sign.
     
  7. Apr 15, 2019 at 3:59 PM #7

    HomeBuilt101

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    >If you kept the oil you drained out, did you wash the oil with clean thinner and pour it through a filter? And check the inside of the oil filter to see what kind of contamination is in it too?


    That would have been a good idea. I did not do the clean thinner and solvent trick however I did drain the oil through a fine mesh screen and it was completely clean.
     
  8. Apr 15, 2019 at 4:16 PM #8

    kent Ashton

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    IMO, the picture you posted shows a worn-out impeller. The wear pattern on the teeth is uneven seeming to indicate the left impeller did not mesh with the other impeller correctly. There is scoring (swirl marks) in the housing and ragged aluminum in the housing leftover from the scoring. Scoring is visible on the surface of both impellers, and on the shaft. That is not present on new parts. I doubt this was a "new" impeller. Apparently you've had low oil pressure in this engine from the start so I would guess the oil pump was defective from the start. If I owned this engine, I would take it apart and examine bearings for embedded metal and crank journals for scoring.
     
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  9. Apr 15, 2019 at 4:50 PM #9

    Dan Thomas

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    That sort of scoring is rather normal. The oil pump is upstream of the oil filter, so anything laying in the case goes through it. If the engine has a spin-on filter, it will trap anything coming off the pump.

    An AD on Lycoming pumps. Scroll about halfway down the page to the AD itself: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/5DE5ACBD6CBC8B2A8625684D00643AC1?OpenDocument&Highlight=io-540 oil pump

    That pump and maybe the shaft look like they might be sintered. And that shaft didn't wear like that in 170 hours.

    The referenced Lycoming SB: https://www.lycoming.com/sites/default/files/Replacement of Sintered Iron Oil Pump Impellers.pdf
     
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  10. Apr 15, 2019 at 4:54 PM #10

    Dan Thomas

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    Check the pump clearances in accordance with the Lycoming Direct-Drive Overhaul Manual, especially the pump gear end clearances to the cover plate, which is the biggest leak. And see that the cover fits the housing perfectly.

    How did the accessory cover gasket look?
     
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  11. Apr 15, 2019 at 10:58 PM #11

    HomeBuilt101

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    THANKS everyone for your help!!!

    The accessory case gasket appeared to be intact and it had the gasket material around the oil pressure sensor port...good thinking!!!

    I am certainly going to replace the impellers and pump body.

    Does anyone have an economical source for the components?

    While doing research I discovered a Service Letter about a procedure to drill the accessory case with an 1/8 inch hole down at a 35 degree angle to provide the driven impeller some extra oil flow and the letter said that if your engine has a driven impeller shaft that is held on with a cotter pin...or a high volume pump...then this procedure should not be performed. I inspected the cover and it does not have the drilled hole.

    My take away is that there is a high volume oil pump available for the IO-540.

    Does anyone know if it will fit on the 76096V accessory case?
     

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