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Thread: O-290 piston/ring sets

  1. #1

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    O-290 piston/ring sets

    Hey all,
    I'm thinking about have a short run of pistons for O-290 made. 8.25:1 and 10:1. Standard and .020 over. New pins, buttons and rings for your cylinders. Chrome, moly faced or cast iron. $1295/engine set. Just throwing it out there to see if there is interest.

    Dana LaBounty
    Sumter South Carolina
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  2. #2
    Clayton Harper's Avatar
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    Is it OK to copy this post on the ShortWingPipers.org? There is a bunch of O-290 guys there.
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  3. #3

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    You can copy and spread it wherever but these are NOT going to be PMA parts so they may be useless to some. I also have them listed on Barstormers.

  4. #4
    Steve Pierce's Avatar
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    Owner produced parts?
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  5. #5
    tcraft128's Avatar
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    Count me in for a set of 10:1's if that price includes the pistons and rings. My RV3 could use a little more punch.
    Turning money into noise since 1996

    Our Build here

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  6. #6

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    Quote Originally Posted by Steve Pierce View Post
    Owner produced parts?
    Doesn't count as owner produced, it doesn't meet type design.


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  7. #7
    Steve Pierce's Avatar
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    Quote Originally Posted by dgapilot View Post
    Doesn't count as owner produced, it doesn't meet type design.


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    True, standard is 7.5 to 1. Was thinking it was 8.5 to 1.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  8. #8

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    What would an 0-290 be putting out for power with 10:1 compression?

  9. #9

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    Add 4% for every 1 point increase in compression. Sets include new pins fitted to pistons, pin buttons in brass or aluminum AND rings in moly, chrome or cast iron. All 4 cylinders serviced. I highly recommend straight bored cylinders with these pistons and rings.

  10. #10

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    I need $300 deposit and 3 orders for each combo of either 8.25 or 10 and standard or .020 over. Most of the airboat guys are going 10:1.

  11. #11
    Clayton Harper's Avatar
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    Quote Originally Posted by Steve Pierce View Post
    True, standard is 7.5 to 1. Was thinking it was 8.5 to 1.
    That's what I thought, Owner Produced Part. I would order mine as 7.5 to 1 and if it wasn't exactly that, Oh Well. Bet it would put out 150HP.

  12. #12

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    O-290 come in 6.5, 7.0 and 7.5. These pistons won't have any markings so, stamp them and run them. Unlike NASCAR they aint got a whistle check on any runway I know of.

  13. #13
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    Bought an STC one time to add 0235-L2C pistons to an 0235C-1, raising the compression from 6.5 to 8.5:1 as I recall. One of the requirements was to change the cylinder corner hold down studs from 3/8" to 7/16"? Something to ponder if going to 10:1. Also the recommendation for straight bored cylinders caught my attention. Danal, is this recommendation specifically for this application or are you a fan of straight bored cylinders in general? Comments? Thanks, Jim

  14. #14
    Steve Pierce's Avatar
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    and then there is the already low TBO and the AD to retard the timing on the O-290-D2. I have heard the stories that this was all a ploy by Lycoming to sell more O-320s.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  15. #15

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    All of this has more to do with type of piston construction and ring design. Keystone rings and choke bores are there to keep the rings from micro welding/sticking in the lands of a cast piston. Anodize the top land of a cast piston, install straight rings and run in a straight bore. Best yet, forged piston, straight rings and straight bore. The only reason for a choke bore is to keep the rings from sticking in a cast piston. It has NOTHING to do with expansion of the top of the cylinder or any of the other old wives tales. Period, the end.
    Thanks 180Marty, cruiser thanked for this post

  16. #16

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    An O-290 running high compression pistons would be a hoot to fly in a lightweight cub, but there's still the issue of expensive/hard to find cylinders. What about line-boring your cade to accept 0-320 cylinders? I know this has been done before, seems like this may be a good option also. Thoughts?

  17. #17

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    Boring the case for O-320 cylinders is fine. Don't forget the O-320 sump, runners and carb. I have a lifetime supply of O-290 cylinders being plated back to standard straight bore. I also have 7/16" stem exhaust valves being made. Just another iron in the fire.
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  18. #18
    Steve Pierce's Avatar
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    I was thinking cylinder shops were installing the 1/2" valves in the 290. Why use the 7/16"?
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  19. #19

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    They are, because I can. Less mass for the spring to deal with and less obstruction in the port. Oh, and less cost.

  20. #20
    Steve Pierce's Avatar
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    But haven't there been issues with breaking 7/16" valves? You can haven7/16" made cheaper than you can buy 1/2" valves?
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  21. #21

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    I'm having mine made in Titanium and there will also be a flow improvement. Corrosion and resulting breakage will be eliminated. The material used with the 7/16" was inferior to the 1/2" so, not that the 1/2" is any better choice except for the material. I'm falling back on my experience working on Cosworth Indy car engines back in the '80's.

    Dana LaBounty
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  22. #22

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    Sounds like an interesting powerplant you're building. What else are you doing to it? Port and polish? I'd like to know more about it!

  23. #23

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    Dana, On the valves you are having made, would it be worth it to go down to 11/32 stems which are so damn common and have guides or guide inserts made?

  24. #24

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    I just got a request for 1500 valves with 13/32" stems so that's where I'll go. What I'm doing with my cylinders is pretty mild. Any port work will be limited to the 1" nearest the valve seat. Remove or blend any casting imperfections, polish exhaust port and stipple intake port to induce boundry turbulence.
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  25. #25

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    Stipple? As in dimples like a golf ball? How is it done?


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  26. #26

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    I have a couple sizes of air driven tools almost like oversized etching tools. I did know a guy years ago that did dimple combustion chambers. I never really got into it but have thought about it again recently. The dimples are the reason a golf ball is so much more efficient in flight. Boundary layer turbulence acts like ball bearings for the air.
    I started this thread thinking someone may be interested in some pistons for experimental O-290's. Any takers?

    Dana LaBounty
    The "Possum Works"

  27. #27

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    With those 11/32 Ex valve stems you can clean up the guide interference of the flow on the roof of the port a fair amount. Still can not do much for the way to tight short side radius of the ports.
    I may take the time to put a cylinder on the flow bench and see what a pitot tube shows. Not sure I want to though since these are such old technology and to risky to try and improve properly.

  28. #28

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    CharlieN,

    Ditto not flow benching. I don't spend more than 30 minutes per head and only look to keep velocity up. Not enough RPM to waste time where there is no benefit. As an aside, took delivery of a new Miller Syncrowave 210 a couple weeks ago. This thing is the cats ass for just working for myself. Anyone thinking about getting a TIG setup, I can't say enough good about it. Got mine from Cyberweld for under $2500 with the Miller rebate and it came with a Spoolmate 150 for shooting aluminum wire.

  29. #29

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    Nice buy on the Syncrowave, My Syncro 250 is 26 YO now and of my 3 Tig machines is by far the favorite. The $1300 circuit board a decade ago from a lightning strike was bothersome but I will not give that machine up.

  30. #30

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    Yeh, rebuilt the Onan twin on my old Trailblazer 250G and a guy just had to have it with a wire feed and HF box. He gave me $4k so I feel reel good about "down sizing".
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  31. #31

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    Now but 0-435 or G0-435 cylinders on that 0-290 and you will have something.

    Jim

  32. #32

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    Jim,
    Not to forget all the valvetrain bits needed for the conversion. I'm all about simple. Straight bore plated cylinders in standard size. 8.25 comp pistons with cast iron rings make for an good running 155 takeoff hp. and 145 cruise hp. If you really want to start swapping parts, find a O-340 crank and install with GPU 6.5 comp. forged pistons running just the top 3 rings. 315 cu. inch and 10:1 comp. I got a million combinations but not a million dollars. I'm just about quick and cheap, run what you already have kicking around.

    Dana LaBounty
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    "The Awesome Possum"
    Bistro and Bait

  33. #33

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    What's the advantage of the O-435 cylinders?

  34. #34

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    Not all O-435, some angle valve. Heavier too. For all the effort no real advantage as the ports are still not anything better.

  35. #35

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    Dana, will you need to retard the timing with the higher compression? I know with 7.5:1, retarding 18 degrees btc is required, just wondering if you'll need to go even more than that?

  36. #36

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    Retard for 7.5 comp was specified for 80/87 fuel. 100LL, non issue. Run timing like a 160hp O-320. Next question.
    Thanks 1934A thanked for this post

  37. #37

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    I would be interested in a set of 7.5 or lower compression pistons w/pins & rings.

  38. #38

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    Why lower the compression and suffer reduced combustion efficiency? I'm curious. I just had pins made from H13 tool steel and the first batch of 8.5:1 pistons are in line for production. I'll have them ready to ship in 5 weeks. Rings are on hand as well as the pin buttons. Best option is to have oversize cylinders plated to standard and STRAIGHT BORED. Let you O-290 perform like a modern engine.

  39. #39

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    Starting a Tcraft EAB build and have a bunch of cheap 0-290 options local so I'm keeping you in mind. Not fully set on engine though.

  40. #40

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    Hey all,

    Just bumping this as I have piston sets on hand. These things are beautiful and weight came in at 970 grams. Stock 6.5 piston is a tick over 1100 grams.

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