Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 19 of 19

  1. #1

    Join Date
    Dec 2002
    Location
    Lake Cowichan, BC, CANADA
    Posts
    1,341
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    OS gemeni 120 connecting rods

    Hello; I (vaugely) remember Brian Winch talking (writing really) about early FT 120's coming out with connecting rods that would break after a few uses. I think it was in RC Report magazine a few months ago. I have come into an old FT 120 that has aluminum die cast rods with OS cast into them, and I'm pretty sure that those are the rods he was mentioning.

    This particular engine suffered a crank failure, the web between the two crank throws fractured, but has been welded up and balanced, so now all I have to do is polish the mains (to get a bit of welding spatter off) and re-assemble it, to try it out.

    I don't want to finish the job if there's a chance that the rods aren't up to the job. I will post pictures if it'll help.

    Any body remember that? Brian are you on?
    t

  2. #2
    MX240's Avatar
    Join Date
    Nov 2003
    Location
    PoDunk City, NE
    Posts
    978
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    T,
    I remember OS had listed the serial numbers of these older engines. Might check their website.
    I have it copied down somewhere in my file.
    I have one of these old 120 twins on a cub...which dosen't do any full power dives.

  3. #3
    Moderator w8ye's Avatar
    Join Date
    Dec 2001
    Location
    Shelby, OH
    Posts
    37,112
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    The welded crank needs to be normalized to relieve the stresses caused by the welding or they may crack again at the edge of the weld
    Attended the CutFinger Institute of DirtNap University for years but never did graduate....
    Recipient, Mangledhand award August 2008
    Club Saito Member #7
    Original AMA #31261

  4. #4

    Join Date
    Sep 2003
    Location
    Jefferson, MO
    Posts
    654
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    I would use the rods you have. I am sure they will out last that welded crank by a long way. Not many people around that have the skills to weld a crank and if they have the skill they would definitly cover the journals.

  5. #5
    L48's Avatar
    Join Date
    Jan 2002
    Location
    Indianapolis, IN
    Posts
    175
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Does the Gemeni 160 have the same problem?
    What, me worry

  6. #6
    MX240's Avatar
    Join Date
    Nov 2003
    Location
    PoDunk City, NE
    Posts
    978
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    As far as I know the OS 160 is OK.
    I haven't heard of any problems of this kind with the 160.
    I have one and it is a very good twin.
    Jim

  7. #7

    Join Date
    Apr 2003
    Location
    Great Mills, MD
    Posts
    2,223
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    The 120 II and 160 are almost the same engine. The early 120 twin is a different animal and is only similar in its looks.

  8. #8
    PlaneKrazee's Avatar
    Join Date
    May 2002
    Location
    Gales Ferry, CT
    Posts
    4,876
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    The 160 twin is a great engine, no problems with rods.
    a never-ending battle for truth, justice and the American way

  9. #9

    Join Date
    Oct 2007
    Location
    Vancouver, WA
    Posts
    168
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Jim,
    I've got one of the original FT 120 Gemini Twins and I have checked the OS website but was not able to find any serial numbers. If you come across your list would you mind posting them?

    Thanks,

    Tip

  10. #10

    Join Date
    Apr 2003
    Location
    Great Mills, MD
    Posts
    2,223
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    This is from the OS help forum: http://www.rcuniverse.com/forum/m_69...tm.htm#6983785

    I had read it there before because I own a FT 120II and was there digging up info on my engine.

    Mike

  11. #11
    MX240's Avatar
    Join Date
    Nov 2003
    Location
    PoDunk City, NE
    Posts
    978
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    OK Tip,
    After some looking through my messy file I did find the paper work on our OS engines.
    Remember, I have't looked at this stuff for years and I didn't have this quite right.
    I got this information off a old torn out yellow page of High Flight Quarterly newspaper.
    It reads:
    Some information for owerners of OS FS102 (old style), FT160 twin engines. The early OS 120 engines that are marked with the letters RP under the engine mount lug are somethimes prone to a case separation at the rear crankshaft bearing. If you have one of these engines, carefully inspect the outside of the crankcase around the rear bearing boss for cracks. Some of the O.S. FT160 twins have a possible defectiver connecting rod set. Check the serial number stamped on a small machines flat at the bottom of the crankcase, just behind the carburetor. If it matches one in the series listed below, again, contact you're dealer.
    The serial numbers are: 000105-128.....130-189......191-236.....350-473....493-672....001050-1052
    001064.....1074.....1077.....1079.....1088.....108 9.....1091
    The engines beginning with serial number 001096 and above are all O.K.

  12. #12

    Join Date
    Jan 2002
    Location
    Hesperia Michigan, MI
    Posts
    12,550
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods


    ORIGINAL: donkey doctor

    Hello; I (vaugely) remember Brian Winch talking (writing really) about early FT 120's coming out with connecting rods that would break after a few uses. I think it was in RC Report magazine a few months ago. I have come into an old FT 120 that has aluminum die cast rods with OS cast into them, and I'm pretty sure that those are the rods he was mentioning.

    This particular engine suffered a crank failure, the web between the two crank throws fractured, but has been welded up and balanced, so now all I have to do is polish the mains (to get a bit of welding spatter off) and re-assemble it, to try it out.

    I don't want to finish the job if there's a chance that the rods aren't up to the job. I will post pictures if it'll help.

    Any body remember that? Brian are you on?
    t
    It always helps to post photos...give it a go. Thanks Capt,n
    Imagination is far more important than knowledge. Albert Einstein.

    http://www.lambertsrc.com/

  13. #13
    Marcol's Avatar
    Join Date
    Mar 2006
    Location
    King\'s Lynn, UNITED KINGDOM
    Posts
    275
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Mmmmmm a welded twin throw crank.


    Good luck

  14. #14
    L48's Avatar
    Join Date
    Jan 2002
    Location
    Indianapolis, IN
    Posts
    175
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Ok I give up, I have looked on the bottom of my 160 and yes there is a flat surface behind the carb. but no numbers. Is this engine good bad or what-ever?
    What, me worry

  15. #15

    Join Date
    Dec 2002
    Location
    Lake Cowichan, BC, CANADA
    Posts
    1,341
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Hello; Well, I have been assembling the FT 120, and encountered a bit of a road block. I crocus clothed the crank throws until I'm satisfied that they'll be okay. It's hard to measure but I tried for 3 thou clearance. I have the bottom end done but I can't find the line nut that holds the intake to the head on one side, also 3 of the 8 O-rings on the push rod tubes are missing. Thje engine was diss-assembled when I got it. Also there are two sleeves that look like dowells, about 1/4 long and `1/4 high that I can't find a place for.

    I admire the mechanics in Cuba, those guys can fix anything, no matter how bad. Who says that only the newest technology is best? When I was last there, I met a fellow with a 57 Ford that he was doing a brake reline on. It was just another job to him. The pieces were junk, comp[ared to what we see all the time, but he gives a one year warrantee on his jobs and only charges the american equivalent of $1.25/hour. He is willing to barter too.

    Any idea on the sleeves/dowells?

  16. #16
    Moderator w8ye's Avatar
    Join Date
    Dec 2001
    Location
    Shelby, OH
    Posts
    37,112
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Attended the CutFinger Institute of DirtNap University for years but never did graduate....
    Recipient, Mangledhand award August 2008
    Club Saito Member #7
    Original AMA #31261

  17. #17

    Join Date
    Sep 2003
    Location
    Jefferson, MO
    Posts
    654
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Here is the part number for the nut and washer.

    http://www3.towerhobbies.com/cgi-bin...?&I=LXCM05&P=V

  18. #18

    Join Date
    Dec 2002
    Location
    Lake Cowichan, BC, CANADA
    Posts
    1,341
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    Hello; Thanks for the help. Here's a picture of the engine. To this stage it spins pretty freely, no binding or tight spots. It's the end that goes into the head, that I need the line nut for, I have the carb to pipe stuff. I'm thinking that the dowell is a spacer for the rocker shaft, which wasn't installed.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Sq46465.jpg 
Views:	12 
Size:	77.4 KB 
ID:	1062263   Click image for larger version. 

Name:	Sn41824.jpg 
Views:	8 
Size:	94.4 KB 
ID:	1062264  

  19. #19

    Join Date
    Sep 2003
    Location
    Jefferson, MO
    Posts
    654
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: OS gemeni 120 connecting rods

    The dowels go on the plate that bolts to the back of the engine. The nuts for the pipe are the same size for the exhaust and the intake (pretty sure). Try one and see.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 12:38 AM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.