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Subject: bad ringgear

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THAD    Posted 01-29-2019 at 15:44:48 [URL] [DELETE]        [Reply] [Email]  
  • bad ringgear
  • hi guys it appears i have a bad tooth on the ring gear how hard is it to split a 1948 ford8n to replace the gear

    Rustyal    Posted 02-01-2019 at 09:31:59 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • It is easy to replace. But you need a torch to heat the ring. It is a shrink fit.

    Tim Daley(MI)    Posted 01-31-2019 at 08:17:37 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • HiYa Thad-
    If you are talking about the flywheel ringgear, then yes, you have to split the tractor to remove the whole assembly. The I&T FO-4 Manual, Page 44 in my 2000 version, has the how-to procedure. Now, it is your tractor and you can do what you want, but I have to ask, is there a problem now? If the tractor starts and runs fine now, I wouldn't worry about a chipped tooth or two. If starter not engaging, you might want to pull the starter and observe if the Bendix is boogered up. If so, it's a lot easier and cheaper to pull and rebuild the starter than splitting the tractor. Just sayin' -it's kind of a big job to split.

    Tim Daley(MI)

    K.LaRue-VA    Posted 01-31-2019 at 10:25:02 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Great suggestion! I fixed a dozen or so bad teeth on one flywheel rather than deal with splitting and replacing the ring gear. The bad spot was occasionally keeping the starter from engaging. I removed the sharp edges with a triangular shaped file, working thru the starter hole. Put starter back in with a new drive on it and haven't had any more trouble with that one.

    Dean    Posted 02-02-2019 at 11:12:35 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Bingo, K.

    Done the same myself.

    Such repairs will usually last years (decades?) for our infrequently started Ns.

    Another ho-made "fix" is to pull the engine over a bit with the fan upon each shut down. Engines usually stop in nearly the same position upon shut down so ring gear teeth wear accordingly. Why not use some other teeth?


    Bruce(OR)    Posted 01-29-2019 at 20:27:15 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • I'm slow. Took about 4 hours. Level gravel driveway, two sheets of plywood, one bottle jack, one floor jack, wedges to keep the front from tilting and 3/8 X 16 4" studs to line up the housings going back together. Don't slide in? Engage the PTO and turn the outside shaft.
    Ring gear was in her oven, set on high 30 minutes, flywheel in freezer if possible.
    Pull from oven with pliers, drop onto plywood on kitchen floor, two hammers and tap into position.
    Let cool before handling it.

    Dean    Posted 02-02-2019 at 11:06:30 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Good "make do with what you've got" procedure.

    My compliments to the chef.


    K.LaRue-VA    Posted 01-30-2019 at 10:38:30 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Our kitchen over didn't even come close, even with the flywheel sitting in 6" of snow on the deck. The FO-4 says 350 degrees. We tried that, then cranked the oven as high as it would go. The ring gear still just went "clang" and failed to slip on. Several weeks later a good bed of hardwood coals in the wood stove did the trick. Laid the ring gear in coals for about 10 minutes. Coals were hotter in the back so turned the gear 180 degrees and closed the door for another 10 minutes. The trick is to get it just hot enough to expand and slip on the flywheel, but not so hot it ruins the temper. At the time I figured the magic temperature to expand my ring gear to fit my flywheel was between 600 and 700 degrees. Your experience may vary depending on how close to factory tolerance your replacement ring gear was manufactured.

    Tim Daley(MI)    Posted 01-31-2019 at 07:56:43 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • I was supervisor of NC turning department and processed/machined Ford service 6375 flywheels for 20 years and we did the complete manufacturing operations like drilling, tapping, refacing, ringgear assembling, balancing, and packing. The flywheel ringgear diameter is +/- .002" and the ringgear ID is .060" under the nominal OD size of flywheel. Ringgears were heated in gas oven and assembled by a human. The time in the oven was regulated because if it got too hot the gear would warp and not seat properly. The OEM drawing defined an ID chamfer on one side of the ringgear and that side was designated to be assembled face down on ring gear seat of flywheel. The reason why is the flywheel had a .015" max radius and if ringgear was upside down would not seat properly. After they cooled, a human worker went over each one with a 5# steel hammer and a steel punch and if the ringgear was not seated had to pound it down flush. Todays aftermarket gears are made with the chamfer on both sides so it doesn't matter, but I'd look to be sure. After ringgear was installed, the assembled flywheels came back to my turning department for the refacing operation for the clutch plate surface. That face had to be perpendicular to the crank bore within .005", runout of clutch face within .005" TIR, clutch face maximum concaveness at .005" and a convex face not allowed. I can't speak of todays' aftermarket ringgear quality, but probably not but a few suppliers of them.

    Tim Daley(MI)

    TheOldHokie    Posted 01-31-2019 at 08:35:06 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Sounds about right. Using 12" as the ID of the ring gear. 060 as the increase in diameter needed, and .0000075 as the expansion coefficient for steel you get a temperature delta dead on Kevin's 600-700 number:

    .060 / 12 / .0000075 = Δ 667 F


    Bruce(OR)    Posted 01-30-2019 at 12:07:20 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • I believe the highest setting on the oven is "Broil" which engages the top burner.
    if the top burner is not working, you might not get hot enough.
    IF the wife will let you use the oven. . . And the corner of the bedroom to store the crankshaft and camshaft in until you get ready to put the engine together. . . and the other room to store the sheet metal in to help the paint cure. . .
    Just remember after she does this for you, she gets to play on the tractor also.
    However, if she doesn't. . . .NO TRACTOR!

    K.LaRue-VA    Posted 01-30-2019 at 16:10:02 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Convincing the wife to "cook" a ring gear in the oven wasn't as hard as I thought. She got curious about the process when I showed her the interference fit and explained that heating the ring gear would make it expand enough to just slip on. For the final attempt she broiled the thing until it was as hot as that oven was going to get it. The flywheel was just outside the door sitting on the deck. All I had to do was grab it with vice grips take two steps and drop it on the flywheel as she opened the door. It's a miracle neither of us got burned doing that little dance. She was more disappointed than I was when it didn't work. Later I carefully measured the ring gear and flywheel, did some math, and figured it would take a differential temp. of 600 to 700 degrees. I suspect the actual as-found dimensions of flywheels and replacement ring gears varies enough that it's a coin flip whether a household oven will do the job. Some of the ring gears have also come loose and people have had to tack weld them to the flywheel.

    Bruce(OR)    Posted 01-31-2019 at 18:33:09 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • Yeah, the convincing wasn't too hard and once it got out the oven, it barely went on.
    The hammers came in handy with a few taps. Nothing hard, but still I figure it should have been warmer than it was coming out.
    Tat was about 80 hours of run time ago and still working.

    JMOR    Posted 01-29-2019 at 19:31:35 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • no split. just remove right trumpet.. now, pinion is another matter.

    THAD    Posted 01-29-2019 at 20:02:50 [URL] [DELETE]        [Reply] [Email]  
  • starter ring gear
  • i mean the starter ring gear on the flywheel

    duey    Posted 01-29-2019 at 19:51:53 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • The "right or proper" trumpet would be the LEFT trumpet.... or is my memory in the ditch again... My apologies if I'm wrong..

    JMOR    Posted 01-30-2019 at 00:03:24 [URL] [DELETE]        [Reply] [No Email]  
  • Re: bad ringgear
  • U are correct, the right one to remove is the left one. :)

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