Rotating Ring Gear

Wed Aug 26, 2009 8:26 pm

Recently my MH Pony began to have slippage between the starter and flywheel. I expected worn teeth on the Bendix and they do show a bit of wear. However, the major contributor to the problem is wear on ring gear teeth at selected spots. I plan to remove, rotate and reinstall the ring gear so that the Bendix contacts parts of the ring gear which show little wear. The method of removal as described by my service manual (drill with 3/16 drill bit then cut with cold chisel) should work well if a new gear is to be installed. But that doesn't work for me as I plan to rotate and reuse the gear. It suggests that the gear should be heated 560-570 degrees for installation. I plan to remove the flywheel, then have a friend use a cutting torch to heat the ring gear. Now my questions: A. The flywheel will be absorbing heat as the heat is applied to the ring gear. So both units will be expanding. Does this present a serious problem and, if so, how do I overcome it? B. How should I mark the area of the flywheel where the worn teeth were located to ensure that following reinstallation the area contains teeth with little to no wear? C. What is meant by the following statement? "Maximum flywheel runout is not to exceed .004 in. as read with a dial indicator gauge". D. Since the margin of the flywheel is wider that that of the ring gear, where should the ring gear be positioned? Maybe that is what item C describes? This is my first attempt at this process. I will appreciate all advice which you provide. Thanks, Dan

Re: Rotating Ring Gear

Wed Aug 26, 2009 8:48 pm

Dan - I think I would try tapping the ring gear off cold or trying to quickly heat the ring gear and attempting removal before the flywheel has time to absorb too much heat. Mark a spot on the flywheel and ring gear so you will know where the gear is now, then you can rotate the worn spots by using the mark as a reference. Chalk works well for this. Runout is how far off you are from the center of rotation.

Re: Rotating Ring Gear

Thu Aug 27, 2009 7:26 am

Dan I agree with Bigdog. I have never had to use heat to get the ring gear off just on. I use a hammer and drift to knock it off. You may have to work around the whole ring a few times. It may not move much on the first pass but it will go I never drive it much more that a 1/8 inch in one pass. Make sure the edge of the flywheel is clean that ring gear has to slide over.

Dan can you flip the ring gear :?: Thats what I have always done taking the gear off fliping 180 deg and putting it back on so that all good teeth face the starter.

Billy

Re: Rotating Ring Gear

Thu Aug 27, 2009 9:02 am

Thanks, Billy and BD. I am glad to hear that it is relatively easy to remove the ring gear as I had expected that to be the most difficult part of the operation. Flipping the gear also seems to be a better solution than rotating it. I am still having problems understanding the term "runout". Try explaining that again, please. Thanks, Dan

Re: Rotating Ring Gear

Thu Aug 27, 2009 9:20 am

Dan England wrote:"Maximum flywheel runout is not to exceed .004 in. as read with a dial indicator gauge". D. Since the margin of the flywheel is wider that that of the ring gear, where should the ring gear be positioned? I am still having problems understanding the term "runout". Try explaining that again, please.
Accurately measure the ring gear location from either the front or rear of the flywheel. You want to put the reversed ring gear back into the same exact location. The exact same distance.

Runout = wobble or deflection.

Re: Rotating Ring Gear

Thu Aug 27, 2009 9:59 am

Thanks, Eugene. Your response clears up my questions on the process. In-so-far as flipping the ring gear, my son suggested yesterday afternoon that I do that. But I thought that I remembered hearing that ring gear teeth were set at an angle and would not mesh properly if flipped. However, at seventy-three years of age I sometimes have very clear, very vivid memories of events/conversations which never occurred. And that must be the case here. Thanks to each of you. Rudi, if you would like me to I will take pics and maybe develop an entry to the "How To" forum. I will be working on a Pony, not a Cub, (as is the article on refurbishing a steering wheel) but the process should be the same. Dan
Last edited by Dan England on Thu Aug 27, 2009 2:40 pm, edited 1 time in total.

Re: Rotating Ring Gear

Thu Aug 27, 2009 10:16 am

I'm not familiar with the details of that engine. However, some general cautions/thoughts:

Some flywheels have a slight lip where the ring gear mounts. It takes quite a lot of heat to get the ring gear over the lip. Check if this flywheel has one before you try to knock the gear off cold. Many ring gears have beveled edges only on one side of the teeth, giving a distinct front and back side. If yours is like that, I would rotate it 90 degrees and keep the same side up rather than flip it over.

I'll try different wording on runout. It is how much the ring gear varies from running true. There are 2 measures, radial and axial (or longitudinal). Radial runout is how much something is like a lobe on a camshaft. The radius of the gear is slightly different if checked at different positions around the gear. Axial runout (the wobble) is the same idea, except measured parallel to the shaft the gear is running on. I presume the runout spec you have is for axial runout, which depends on how well the ring gear is installed on the flywheel. Too much runout either directions could be a problem.

Re: Rotating Ring Gear

Thu Aug 27, 2009 10:21 am

Dan,

I think this may be the thread you were referring to http://www.farmallcub.com/phpBB2/viewtopic.php?f=1&t=44073&hilit=Ring+Gear Hope this helps.

Bill

Re: Rotating Ring Gear

Thu Aug 27, 2009 11:28 am

Keep the info coming. I haven't split the tractor yet, maybe next week. Each of the posts has been helpful to me. Dan

Re: Rotating Ring Gear

Thu Aug 27, 2009 11:58 am

I would try Jim Becker's suggestion, rotating the flywheel on the crankshaft - at least look at the possibility of doing so.

On some engines the flywheel is keyed to the crankshaft, either with a stud or off set bolt holes in the crankshaft and can not be repositioned.

The education begins when the tractor is split.

Re: Rotating Ring Gear

Thu Aug 27, 2009 1:33 pm

Eugene: I didn't interpret Jim's statement to suggest rotating the flywheel on the crankshaft but instead to rotate the ring gear 90 degrees on the flywheel. However, rotating the flywheel on the crank would be the easiest fix if it can be done. Dan

Re: Rotating Ring Gear

Thu Aug 27, 2009 6:29 pm

I meant to rotate the ring gear on the flywheel. I think every flywheel I have ever removed was positioned either by a key or a dowel so it could only go one way.

Re: Rotating Ring Gear

Thu Aug 27, 2009 6:53 pm

Dan, place the flywheel on 4X4 blocks , If you have access to a rosebud [ made for heating ] it will only take a few secounds to get the ring gear hot enough to come off. Let the flywheel cool if you like, turn thr flywheel over and place the ring gear where you want it and heat it up. you may have to tap it a bit to get it flush. let it cool and you will be good as new
If you dont have a rosebud, you can use the cutting tip , it will just take a little longer
David

Re: Rotating Ring Gear

Thu Aug 27, 2009 8:11 pm

Dan,

Plenty of good advice here, follow Daves advice as that is the way that I would do this job. Also just rotate the ring gear 90 degrees, do not flip it. Just make sure that the ring gear is seated fully on the flywheel.

The Flywheel runout that the book is talking about is when you replace the existing or original crankshaft or flywheel. You will need to check the radial runout to make sure the new parts run true to the crankshaft centerline. If the runout was off you would have to remove the dowel pins, center the flywheel to the crankshaft then drill and repin the dowels.Too much radial runout will flex and eventually break the center out of the clutch disc or damage the transmission input shaft bearings.

Using the same flywheel and crankshaft means you do not worry about this measurement.

Good Luck

Mark

Re: Rotating Ring Gear

Mon Aug 31, 2009 6:55 am

The following info is taken from the manual "Massey-Harris Pony Tractor Operating and Servicing Instructions" (1949) by Massey-Harris Co.
TO REMOVE THE CLUTCH
1. Drain the cooling system
2. Remove engine sheet metal
3. Remove radiator grille and radiator
4. Disconnect throttle and choke controls, gasoline and oil pressure lines, and ignition cable from engine
5. Remove engine mounting bolts
6. Move engine ahead sufficiently to clear main drive shaft from clutch
7. Remove screws holding clutch assembly to flywheel

To re-assemble follow the above operations in reverse order.

I do not see the need for items 1 and 3. I am splitting the Pony to rotate the ring gear on the flywheel. Can anyone provide reasons why I should include the two items in the process of doing the split? Thanks, Dan