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Thread: Cracked O-320 Case - Best way to proceed?

  1. #41
    mike mcs repair's Avatar
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    sell yours for airboat use.... buy a 180 hp...
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  2. #42
    Gordon Misch's Avatar
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    I would think Nickel would be superior in our climate Gordon
    Thanks Craig. Could you tell me why please? And thanks again for your advice yesterday - - -
    Gordon

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  3. #43
    Gordon Misch's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    Was talking to Ken Tunnel at LyCon a lititle while ago on another matter. He said he saw more cracking with early and middle production wide deck cases than he ever did on narrow decks. There are a few more.pieces you'd have to change if you convert from wide to narrow.
    Thanks Steve. That's pretty consistent with what DivCo had to say. The two tend to crack in different areas. Though he said the wide decks tend to be repairable, while the narrow decks tend to be less so.

    Could you please clue me in on what other pieces would need to be changed?
    Gordon

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  4. #44
    Steve Pierce's Avatar
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    The only thing I remember are the idler shafts that bolt to the back of the case.

    I was at Gibson's cylinder shop when the first set of Nickel cylinders started coming in for overhaul after TBO. Marshal told me the barrels still measured new limits. The other advantage is they don't rust. I have installed quite a few and they have been good. I did have a C85 peel the nickel and contaminated the engine. That was after ECI got bought by Continental and it took some threats to get the repairs taken care of since the cylinders were still under warranty but they did finally step up. Just put 4 new ECI/Continental O-320 cylinders on my Dad's Clipper but he wouldn't spend the extra money for the nickel cylinders. His 1700 hr Millineum cyllinders had some corrosion pitting. He use to fly 130-150 hours a year but now it is more like 40-50. I wish he would have installed the nickel because Memphis is pretty humid but he build an engine dehumidifier.
    Steve Pierce

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  5. #45
    Flying Bee's Avatar
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    Quote Originally Posted by Gordon Misch View Post
    Thanks Craig. Could you tell me why please? And thanks again for your advice yesterday - - -
    Steve pretty much summed it up. I have been fighting low compression in plain steel cylinders at annuals since i bought the plane and all have been leaking by the rings. I've heard from engine builders (including yours) that the nickel breaks in fast and will not rust. Now I am in the middle of overhauling my 320 narrow deck and upgrading to 160hp which requires different cylinders anyway, the Nickel was an easy choice for me. Your scenario may be a little different having decent lower time cylinders making it harder to justify. If your cylinders didn't need a lot of work maybe ask about plating yours? Just an idea
    Craig

  6. #46
    Gordon Misch's Avatar
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    Thanks Steve and Craig. Makes sense re the nickel. It's probably soft in the as-plated condition, then work hardens during break-in.

    I'm still very interested in suggestions for good trustworthy source(s) for exchange cylinders. Suggestions??

    Thanks - -
    Gordon

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  7. #47
    Bill Rusk's Avatar
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    A common misperception is that the narrow deck case is lighter than a wide deck. I spent time at an engine overhaul facility and weighed about 10 different cases. The lightest case is the mid 1960's wide deck by several pounds. After the late 60's the wide deck cases got progressively heavier. The narrow deck case is heavier than a wide deck up to the early to mid 70's.

    Just thought I'd throw that out there

    Bill
    Very Blessed.
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  8. #48
    skywagon8a's Avatar
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    It is my understanding that there is a modification which can be done to the narrow deck cases which installs a bushing or pin which straddles the joint between the two case halves. This helps to prevent the fretting situation which requires the milling of the case haves to correct. I believe that this is one of the things which were done to increase the TBO from 1200 to 2000 hours. Yes changing the valve diameters was also one of the changes.
    N1PA
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  9. #49
    kase's Avatar
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    Alignment dowel on a narrow deck or early wide deck case without body fit thru studs.
    Click image for larger version. 

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  10. #50
    Flying Bee's Avatar
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    [QUOTE=skywagon8a;713775]It is my understanding that there is a modification which can be done to the narrow deck cases which installs a bushing or pin which straddles the joint between the two case halves. This helps to prevent the fretting situation which requires the milling of the case haves to correct. I believe that this is one of the things which were done to increase the TBO from 1200 to 2000 hours. Yes changing the valve diameters was also one of the changes.[/UO]


    The top picture is my 150 narrow deck. And the bottom picture is a freshly overhauled 160 narrrow deck. Notice the extra bushing around the center main thru stud. Is this what you’re referring to Skywagon?

    Click image for larger version. 

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    Craig
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  11. #51
    skywagon8a's Avatar
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    Craig, Yes that is it. Without that bushing the case halves can work against each other (fretting) causing a wearing away of some material. Then the next time that the through bolts are torqued the main bearings get pinched below minimum tolerances.
    N1PA

  12. #52
    Flying Bee's Avatar
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    The cleaner looking side of the center main is severly fretted along with the case being cracked.
    Craig
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  13. #53
    Gordon Misch's Avatar
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    After the late 60's the wide deck cases got progressively heavier.
    Thanks. That's consistent with Steve P.'s info in #37.
    Gordon

    N4328M KTDO

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    Just so you know, those spot faced cylinders you have are not compatible with the cylinder base plates to go to 160 hp....you'd need new narrow deck cylinders without the spot face, longer studs, and a set of base plates to go up 10 hp.....I feel it's not worth the expense.

  15. #55
    Gordon Misch's Avatar
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    Yes, I learned that last week thanks to Flying Bee and confirmed in the parts manual.

    Thank you.
    Gordon

    N4328M KTDO

  16. #56
    Gordon Misch's Avatar
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    If I went from my narrow deck to wide deck with 160 HP cylinders (and any other misc parts changes), is that just a logbook entry? How do I deal with the data plate, currently A2B which would change to B2B?
    Gordon

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  17. #57

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    Quote Originally Posted by Gordon Misch View Post
    If I went from my narrow deck to wide deck with 160 HP cylinders (and any other misc parts changes), is that just a logbook entry? How do I deal with the data plate, currently A2B which would change to B2B?
    Gord,

    no, a widedeck has an A in the serial number. Go to Wikipedia and look up the O320, they have a nice list of the variants of each engine. My understanding is that if you have one model, and convert to anorther, you need a second data plate (depending on the changes).

    don
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  18. #58
    Steve Pierce's Avatar
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    LyCon has an STC but you can also do it IAW the parts manual and TCDS and there is a service bulletin for stamping a C on the data tag for converting from one model to another. Some old threads on this site about it as well.
    Steve Pierce

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  19. #59
    skywagon8a's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    LyCon has an STC but you can also do it IAW the parts manual and TCDS and there is a service bulletin for stamping a C on the data tag for converting from one model to another. Some old threads on this site about it as well.
    I installed a PA-18 with a 160 hp on floats. The 160 was installed with an STC which was limited to land plane only. The engine was converted from 150 to 160 with no 337 or STC records. I checked with the well known engine overhaul facility and they verified what Steve says about using the parts manual along with the TCDS. I solved the landplane limitation by getting a field approval limiting the engine to 150 hp. This was done by placing a new red line on the tach at the 150 hp rpm. With the prop which was on the plane, it wouldn't turn over the 150 hp rpm anyway. So in the end we still had the 160 hp with no limits other than a different red mark on the tach which was only relevant at full power in level flight.

    Gordon, If needed I can show you a copy of this FA. You may be able to use it to assist in getting your own FA for your -12.
    N1PA
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  20. #60
    skywagon8a's Avatar
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    Gordon, I sent you an Email.
    N1PA
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  21. #61
    Gordon Misch's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    LyCon has an STC but you can also do it IAW the parts manual and TCDS and there is a service bulletin for stamping a C on the data tag for converting from one model to another. Some old threads on this site about it as well.
    Thanks Steve - I talked with Lycon this morning about the STC, and am waiting a call back from Ken re the details of the work. Would you happen to have the service bulletin number handy?
    Gordon

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  22. #62
    Flying Bee's Avatar
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    I think it's Service Instruction 1304J
    Craig
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  23. #63
    Gordon Misch's Avatar
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    Quote Originally Posted by Flying Bee View Post
    I think it's Service Instruction 1304J
    Thanks, yes. That one addresses the letter C being added to the data plate. I wasn't having any luck yet searching.
    Gordon

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  24. #64
    Steve Pierce's Avatar
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    You need plated/nitrided cylinders. Ken told me the soft standard steel cylinders will wear the barrels out in a few hundred hours. Sent him an engine recently for prop strike inspection that had been recently converted to 160 hp by the owner. He argued with Ken that he did everything IAW the STC when he got a phone call about the soft steel cylinders and the gouged hone job. He called me complaining that he did it just like the STC as well. He didn't realize he was talking to the guy who owned the STC so he probably knew what he was talking about.
    Steve Pierce

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  25. #65
    moneyburner's Avatar
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    Quote Originally Posted by Gordon Misch View Post
    Well, DivCo says my case is not repairable due to the location of the crack. So I'm looking at a "new" case for sure. Now the question is whether to stay with 150 HP or upgrade to 160 HP. DivCo has narrow deck low compression and wide deck cases in inventory, and they are the same price. They don't have the high compression narrow deck, and cost to convert would be prohibitive. In the opinion of Lucas, the gentleman I talked with there, neither narrow nor wide is better than the other overall.

    160 HP is tempting, but would require different engine STC (Crosswinds?) and different mogas STC (Peterson) I currently have the spotfaced (low compression) narrow deck cylinders with about 480 hours since major overhaul. So conversion would mean get a wide deck case and compatible cylinders. My current cylinders have around 500 hours on them, compressions in the mid to upper 70's at last annual.

    Two questions:
    What firms would you recommend for exchange cylinders?
    What's best - steel, chrome, nickel, or nitride? Why? I typically fly around 100+ hours per year. Humid climate, but hangared.

    Thanks!
    Can you use mogas with a 160? I have an 0-320-B2B and it needs 100LL. Maybe I didn't look into it far enough?
    Quidquid Latine dictum sit, altum videtur

  26. #66
    moneyburner's Avatar
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    Quote Originally Posted by skywagon8a View Post
    Craig, Yes that is it. Without that bushing the case halves can work against each other (fretting) causing a wearing away of some material. Then the next time that the through bolts are torqued the main bearings get pinched below minimum tolerances.
    That happened to mine. It was real hard to start when warm; mis-diagnosed as a failing starter until hand-propping was tried. The bearings were actually squeezing the crank when it was hot. Dodged a bullet with that one.
    Quidquid Latine dictum sit, altum videtur
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  27. #67
    Gordon Misch's Avatar
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    Can you use mogas with a 160? I have an 0-320-B2B and it needs 100LL. Maybe I didn't look into it far enough?
    Yes, the Peterson STC will cover it. http://www.autofuelstc.com/order_online.phtml
    Gordon

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  28. #68

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    Tell us more about soft steel barrels? A local 160 Cub with 350 SMO just got an "unfavorable" oil analysis.

    I know nothing about the PA-12 except that Gordon's is an honorary 18 - but having experience with 150, 160, and 180 Super Cubs, I can tell you the 160 version is best by a very wide margin. Opinion. If I ever re-engine my Decathlon, I will look into the 160.
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  29. #69
    Gordon Misch's Avatar
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    Well, I've certainly learned that converting from 150 to 160 turns out to be somewhat more than just bolting on new cylinders, especially when starting with a narrow deck 150. Thanks to help from numerous members here I think I have it figured out, with a reasonable path to accomplishing it. I'll be talking details with my IA (who has very graciously agreed to supervise my work on the project) tomorrow to see if he concurs with my conclusions, and then take action. HOURS of research were involved for this amateur!

    Many thanks to all of you who have helped me with this!

    FWIW, here is my research summary for converting A2B narrow deck 150 HP to B2B wide deck 160 HP, given that an A2B wide deck case is available. No guarantees of this being perfectly accurate. I am not an A&P and this is not advice. It's the best I have to date, so thought I'd share as a preliminary report.


    1. Lycon STC to upgrade horsepower requires wide deck for the 160 engine.
    2. Crosswinds STC (160 HP in PA-12) specifies B2B with round airbox and rear-mount oil cooler. Airbox and rear-mount oil cooler can be deviated by IA discretion (I would want to deviate). Charly sez round airbox gives 10 - 20 additional RPM.
    3. Peterson STC for Mogas requires 91 octane (premium) auto fuel.
    4. AD 98-02-08 for 160 HP O-320 requires crankshaft internal inspection IAW Lycoming SB 505B. The overhaul yellow tag for my existing crankshaft specifies SB 505 complied with. However crank flange is not stamped PID to indicate the internal coating that terminates the AD. So appears to need visual internal inspection and termination of the AD by applying Urethabond 104. The SB specifies all O-320 engines, while the AD specifies only 160 HP versions. Seems like a good idea to re-inspect regardless?
    5. Lycoming Service Instruction 1304J specifies to mark data plate with a “C” as a suffix to the serial number, to indicate modification of the engine model designation.
    6. Lycon says there are some accessory case gear differences between narrow deck and wide deck. The differences weren’t specified on the phone. From the parts manual it looks like just the crankshaft idler gear and bushing.
    7. Per Lycoming parts manual (WCF = wide deck, and STD = narrow deck in parts book nomenclature):
      1. Case same for A2B WCF and B2B WCF
      2. Crankshaft same for A2B STD and B2B WCF (AD 98-02-08 applies)
      3. Crankshaft main bearings DIFFERENT for A2B STD and B2B WCF (fig 1-2)
      4. Crankshaft idler gear and bushing DIFFERENT for A2B STD and B2B WCF (fig 1-7)
      5. Camshaft same for A2B STD and B2B WCF
      6. Lifters same for A2B STD and B2B WCF
      7. Pushrods appear to be the same for all O-320. Different P/N’s available, different lengths? Might need some DIFFERENT length pushrods. Need to consult overhaul manual for determination. Shorter rods will result from milled case halves.
      8. Connecting rods and crankpin bearings same for A2B STD and B2B WCF
      9. Sump same for A2B STD, A2B WCF. and B2B WCF
      10. Piston pins appear to be “heavy” for low compression A models and “regular” for other models. Probably DIFFERENT fig 3-1
      11. Piston pin plug - no mention of what to use with nickel plated cylinders. Probably DIFFERENT Fig 3-1
      12. Accessory housing same for A2B STD and B2B WCF
      13. Carburetor same for A2B STD and B2B WCF Charly Center says carb may need re-jetting to be a little richer.
      14. Magnetos same for A2B STD and B2B WCF
      15. Dipstick same for A2B STD and B2B WCF
    Last edited by Gordon Misch; 03-28-2018 at 11:22 PM.
    Gordon

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  30. #70
    flynlow's Avatar
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    ....or you could just slap in some 8.5 pistons and call it good...

  31. #71

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    Quote Originally Posted by Gordon Misch View Post
    Well, I've certainly learned that converting from 150 to 160 turns out to be somewhat more than just bolting on new cylinders, especially when starting with a narrow deck 150. Thanks to help from numerous members here I think I have it figured out, with a reasonable path to accomplishing it. I'll be talking details with my IA (who has very graciously agreed to supervise my work on the project) tomorrow to see if he concurs with my conclusions, and then take action. HOURS of research were involved for this amateur!

    Many thanks to all of you who have helped me with this!

    FWIW, here is my research summary for converting A2B narrow deck 150 HP to B2B wide deck 160 HP, given that an A2B wide deck case is available. No guarantees of this being perfectly accurate. I am not an A&P and this is not advice. It's the best I have to date, so thought I'd share as a preliminary report.


    1. Lycon STC to upgrade horsepower requires wide deck for the 160 engine.
    2. Crosswinds STC (160 HP in PA-12) specifies B2B with round airbox and rear-mount oil cooler. Airbox and rear-mount oil cooler can be deviated by IA discretion (I would want to deviate). Charly sez round airbox gives 10 - 20 additional RPM.
    3. Peterson STC for Mogas requires 91 octane (premium) auto fuel.
    4. AD 98-02-08 for 160 HP O-320 requires crankshaft internal inspection IAW Lycoming SB 505B. The overhaul yellow tag for my existing crankshaft specifies SB 505 complied with. However crank flange is not stamped PID to indicate the internal coating that terminates the AD. So appears to need visual internal inspection and termination of the AD by applying Urethabond 104. The SB specifies all O-320 engines, while the AD specifies only 160 HP versions. Seems like a good idea to re-inspect regardless?
    5. Lycoming Service Instruction 1304J specifies to mark data plate with a “C” as a suffix to the serial number, to indicate modification of the engine model designation.
    6. Lycon says there are some accessory case gear differences between narrow deck and wide deck. The differences weren’t specified on the phone. From the parts manual it looks like just the crankshaft idler gear and bushing.
    7. Per Lycoming parts manual (WCF = wide deck, and STD = narrow deck in parts book nomenclature):
      1. Case same for A2B WCF and B2B WCF
      2. Crankshaft same for A2B STD and B2B WCF (AD 98-02-08 applies)
      3. Crankshaft main bearings DIFFERENT for A2B STD and B2B WCF (fig 1-2)
      4. Crankshaft idler gear and bushing DIFFERENT for A2B STD and B2B WCF (fig 1-7)
      5. Camshaft same for A2B STD and B2B WCF
      6. Lifters same for A2B STD and B2B WCF
      7. Pushrods appear to be the same for all O-320. Different P/N’s available, different lengths? Might need some DIFFERENT length pushrods. Need to consult overhaul manual for determination. Shorter rods will result from milled case halves.
      8. Connecting rods and crankpin bearings same for A2B STD and B2B WCF
      9. Sump same for A2B STD, A2B WCF. and B2B WCF
      10. Piston pins appear to be “heavy” for low compression A models and “regular” for other models. Probably DIFFERENT fig 3-1
      11. Piston pin plug - no mention of what to use with nickel plated cylinders. Probably DIFFERENT Fig 3-1
      12. Accessory housing same for A2B STD and B2B WCF
      13. Carburetor same for A2B STD and B2B WCF Charly Center says carb may need re-jetting to be a little richer.
      14. Magnetos same for A2B STD and B2B WCF
      15. Dipstick same for A2B STD and B2B WCF
    Gordon......thanks for this synopsis! I am getting ready to do the same project, and this save me a lost of research and work! Have a newly reconditioned narrow deck case, and since I am taking additional parts to Aircraft Specialties on Monday, will take the case to them and see if we can make a trade for the wide deck case. Sounds like my reconditioned crank will work (still standard dimensions). Thanks again!

    Fabricman


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  32. #72
    WhiskeyMike's Avatar
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    Going back to the start of this thread, my 2 cents is that prop strikes can lead to serious issues further down the line, sometimes years apart. THere's generally no warning. It cracked for a reason. That's 1 cent. The other penny is that it's hard to beat new cylinders. Otherwise why have we continually had them last till TBO or beyond without a whisper of trouble vs. bad guides, cracks etc etc. Pay now, or pay later - maybe at a higher price.
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  33. #73
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    Gordon......thanks for this synopsis! I am getting ready to do the same project, and this save me a lost of research and work! Have a newly reconditioned narrow deck case, and since I am taking additional parts to Aircraft Specialties on Monday, will take the case to them and see if we can make a trade for the wide deck case. Sounds like my reconditioned crank will work (still standard dimensions). Thanks again!

    Fabricman



    Although the crankshafts may interchange, there is a difference between the wide deck and narrow deck as the wide deck has a solid flange and the narrow has the "lightening holes"; which need to be monitored for cracks between the holes. (not very common but has happened).

    I have seen narrow deck engines with solid flanges; where the crank was replaced but have not seen a wide deck with the older shaft.
    Ed

  34. #74
    skywagon8a's Avatar
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    Quote Originally Posted by cubpilot2 View Post
    ....the narrow has the "lightening holes"; which need to be monitored for cracks between the holes. (not very common but has happened).
    I have seen this with all of the webs cracked except just one. This on a TriPacer where I was taking the prop off for some reason and found the cracks by accident.
    N1PA
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  35. #75
    mike mcs repair's Avatar
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    Quote Originally Posted by Gordon Misch View Post
    ..

    1. Crosswinds STC (160 HP in PA-12) specifies B2B with round airbox and rear-mount oil cooler. Airbox and rear-mount oil cooler can be deviated by IA discretion (I would want to deviate). Charly sez round airbox gives 10 - 20 additional RPM.

    Atlee's has a nice stainless steel airbag now if you decided to http://www.fadodge.com/carb-heat-box/

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  36. #76
    Gordon Misch's Avatar
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    My IA is willing to approve my requested deviations, however that's good to know. Thanks Mike.
    Gordon

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  37. #77
    Gordon Misch's Avatar
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    Update, now that the engine is disassembled.

    The first thing I saw after splitting the case was significant wear at the aft 1/2" of the front main bearing, and on the center main bearing. Copper was showing from under the babbit in each location. So I feared for crankshaft straightness. Turns out the crank is straight - runout at the center main is .0005 TIR. Also, the main journals measure well within "new" tolerance for .010 undersize. There are flecks in all of the bearing shells, so I expect I'll be replacing the rod bearing shells and bolts also, but will wait for inspection by my IA, first part of the week.

    The wear patterns on the bearing shells suggest over-torquing or fretted case. A straightedge on the parting face shows about .002" gap at the center main bearing and the aft end of the front main bearing on one case half, but almost none on the other. So I suspect fretting damage. The case is scrap, and will be replaced anyway.

    Crankshaft axial clearance is way out of tolerance at .034". New limit is .016 and service limit is .026. The thrust face on the case is lightly scored and obviously worn. The thrust face on the crank has some very small scuff-like roughnesses. I think they will polish out, but need to check with my IA. I need to check for possible partly-plugged oil passage that could possibly contribute to this condition. More likely, given that the aft portion of the front main was squeezed too tight, there would have been reduced oil flow from the main journal aft toward the thrust surface. Just now thought of that, and I bet that's the problem.

    Camshaft is straight with some very light wear on lobes. Lifter faces show some light wear and either prior rust or spalling indications. Again, need IA's opinion on that.

    Bottom line, it appears that the case might not have been "right" when this engine was assembled at overhaul. Once I found the bearing issues inside, I'm glad the engine is apart. This time I will do the assembly myself (supervised by IA) and will be thinking exclusively about the reliability of the engine, rather than how long till 5 o'clock!
    Last edited by Gordon Misch; 04-01-2018 at 11:49 AM.
    Gordon

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    Thanks OLDCROWE, Steve Pierce thanked for this post

  38. #78
    C-FIJK's Avatar
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    Bob i did this last year at overhaul went from 150 -160 wide deck in my 1955 super cub best money spent yet and 82-43 borer prop .


    Quote Originally Posted by bob turner View Post
    Tell us more about soft steel barrels? A local 160 Cub with 350 SMO just got an "unfavorable" oil analysis.

    I know nothing about the PA-12 except that Gordon's is an honorary 18 - but having experience with 150, 160, and 180 Super Cubs, I can tell you the 160 version is best by a very wide margin. Opinion. If I ever re-engine my Decathlon, I will look into the 160.

  39. #79
    Gordon Misch's Avatar
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    Quote Originally Posted by C-FIJK View Post
    Bob i did this last year at overhaul went from 150 -160 wide deck in my 1955 super cub best money spent yet and 82-43 borer prop .
    Gerry, would you be able to share any performance numbers, before and after? For example takeoff distance, rate of climb, fuel consumption. Thanks - -
    Gordon

    N4328M KTDO

  40. #80
    C-FIJK's Avatar
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    Gordon i have no real numbers before and after sorry , rpm is up about 175 more on take off and the plane climbs like never before, this was a huge improvement over the 150 hp i fly on floats and have it at gross weight most often. Gets up on step and pulls hard off the water and in climb .
    Thanks Gordon Misch thanked for this post

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