48' Cub - Get it running - Update

[phill_mi]

Greetings; I drove this 48' Cub, 6v, Magneto, no TC, with a C22 sickle about a 1/2 mile home from a neighbor's yard last fall (Oct '21) and started working on the list of fluid changes suggested in "What to do with a Cub you just brought home"
http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=91765

Many have helped me on specific topics, but after doing some compression tests and getting dismal results, it looks like I need to split the tractor and rebuild the engine. As I start down that path, I am creating this thread to consolidate the posts. Some of the threads up until this point include:
"new cuby, old beek" My into and what little history I know about the cub.
http://farmallcub.com/phpBB2/viewtopic.php?f=14&t=111788
"48 Cub - new fluids, oil pressure gauge" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=111799
"48 Cub - PTO pulley wobbles" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=111824
"48 Cub - starter grinds" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=111943
"gas tank rust" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113261
"'48 Cub with IH Carb bolt thread questions" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113302
"'48 Cub -metal parts in oil pan" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113327
"IH 3/4 Carb bowl gasket" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113372
"'48 Cub Magneto - oil under coil" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113413
"Governor Oil Seal orientation" http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=113423

Since the problem with the starter is unresolved, (it rarely engages the ring gear), I used the hand crank to do the tests. I read on here the advice to get five compression strokes, so I spun the crank 15 to 20 times, and tested each cylinder three times, dry and then wet. The carb was removed at the time. I had checked the valve lash several weeks ago, which for the most part did not need adjustment.
The dry numbers are (1 to 4):
60, 47, 45, 48
57, 48, 47, 43
60, 38, 47, 43

The wet numbers are (1 to 4):
65, 60, 64, 90
69, 63, 56, 80
69, 56, 68, 75

Folks tell me that compression numbers can be very subjective depending on the test process. Most of the tests were done using 15 spins. The last wet cylinder tested, #4, was done using 20 spins. Maybe I should redo all of the tests at 20+ spins but I need to reserve some energy for my upcoming cardiology stress test. Since I also found dark oil on the back of the oil pan in the clutch housing I think the rear seal needs to be replaced. Grim at the front of the engine implies the front seal needs replacing. The governor was missing parts and had run like that for a very long time. The governor seal had about 1" section missing and the underlying spring was worn flat, indicating to me that the problem had been happening for a while. There were parts in the magneto that were broken and had been run for a long time in that condition. The left final drive had very little fluid in it. So as eager as I was to get this tractor working in its old work cloths, I have concluded that this tractor has had a hard life and I need to rebuild the engine. I am not big on painting (anything) and have limited space/tools to do a repaint correctly, so we will see how far I venture that direction. But as soon as I can put some kind of a splitting stand together and make the wedges to stabilize the front axel, I plan to move forward with pulling the engine to work on it. I look forward to, and am thankful for everyone's suggestions and assistance.

[Glen]

Hi,
The compression numbers are low.
The Cub service manual says a Cub engine has 120 lbs of compression. That is probably for a new engine.
Some less is ok, they have said on here 90 lbs or above is ok.

If the engine runs, before doing all the work of a rebuild to the engine, you could try an oil additive.
They say on here to put Seafoam oil additive in the engine oil.
They sell it at auto parts stores.
Several people on here that used it said that it helped a lot.
They say on here to make the engine work while using the additive.
If the piston rings are stuck, it can help free them.

One of the experts on here said to use the additive for 2 oil change periods.
The 1955 Cub operator's manual says to change the oil every 150 hours of use.
If the rings are wornout, the seafoam won't help much.

Here is info for doing a compression test, if you need it.
Open the throttle fully to do the compression test, so the engine can get air.
Have all 4 spark plugs out of the engine at the same time.
Charge the battery fully before the test, and use the starter.
They have said on here use the starter for the test, not the hand crank.
The hand crank is too slow, and the numbers will be less.
I would say turn the engine as many turns as it takes until the pointer on the gauge stops going up.
You will need to repair whatever is wrong with the starter to do a compression test.

The engine may not need a rebuild if the compression test numbers are higher using the starter.

If the oil pressure is good when it is running, that is good.
The oil pressure can be low if the crankshaft bearings are worn.
If the oil pressure is good, even when the engine is hot, the bearings may be good too.
But old crankshaft bearings can be scratched and rough.

[Eugene]

Hand cranking numbers will be perhaps 30% low. Suggest running/working the engine hard for a length of time, then redoing the compression tests.

[phill_mi]

I ran the engine briefly several weeks ago, before I went down the path of adjusting the valve lash, removing the oil pan and finding pieces of a role pin and oil leaking at the back of the pan, and removing the governor to find missing parts and broken parts in the magneto. On that occasion, the only time I have gotten the engine to run since I drove it a half mile home last fall, I only ran it for a few minutes, not enough to warm it up. It was sputtering a lot and not responding to the throttle (probably because of the governor field mods). It took a lot of hand cranking to get it to fire up that time, but I had to shut it down because of a sediment bowl gas leak. So it did not run long enough to learn much about the engine. As I was working on the valves, I also poured seafoam into each spark plug hole to let it set and loosen things up. I think I am going to have to split the tractor to figure out why the starter is not meshing with the ring gear as I have messed with trying to reposition the starter. The starter shop said the bendix was OK and installed new brushes.

[staninlowerAL]

Have you tried to turn the engine slightly and then attempt to start with the starting motor? If the teeth on the ring gear are bad in places this will allow the starting motor to engage the ring gear at a different location. If this is true with your tractor, splitting the tractor is the only way to replace the ring gear.

[Waif]

Heck , it's just getting broke in! l.o.l..

I know you want to split it. Being prepared to is good. With emphasis on safety so not to ruin the pleasure.

Pulling your starter will give you a peek at the ring gear as mentioned.
And your starter bolts allow movement of the starters housing when loose. Like other fasteners with generous specs / allowing easy use , that play can be used to adjust with. Even by using uneven torque.
But check too for a level surface the stater contacts (and the staters face as well) when bolted snug. In case of debris or a casting line or something changing the angle of the dangle away from original intent.

Weak wires bad contacts or low voltage can make a starter seem wonky too.

IF as mentioned you have good oil pressure ; I agree with holding off on a rebuild briefly. Just to see if rings free up a bit and compression goes up a little.

[phill_mi]

Well I wanted to get it running rather than split it, but each part I have worked on has been in very bad shape. Early on I noticed that the ring gear could be repositioned and the starter might engage, but the more I tried that the less success I had. Several weeks ago when I removed the lower cover to remove the oil pan, I found a lot of old oil on the fly wheel and a lot of metal shavings. The old oil was from before I had changed the oil at that point. I had tried to inspect the ring gear through the starter hole prior to this and most of the teeth have a very jagged edge on the front of them. This last weekend I talked the situation over with a mechanic friend and decided to split the tractor, which I have now done. I made hardwood wedges and splitting stand, blocked the wheels and picked the front half off with a cherry picker. I hope to borrow an engine stand tonight. The ring gear seems to only have wear contact on each tooth about 1/4 to 1/2 the depth of the tooth. The leading edge of each tooth seems to have been ground ragged. There is a lot of metal filings all over the bell housing with old black oil. I am reading up on the topic now and waiting for the engine stand before I try to take it apart further.

[Glen]

Hi,
Good you are making progress with the engine.

Below is a listing at TM Tractor for a new flywheel ring gear, you can look at the pics.

http://www.tmtractor.com/new/en/1922fp.htm

I think the original ring gear teeth came with one corner of each tooth filed off, at about a 45 degree angle, so the starter gear would engage easier.
I've never seen a new original ring gear. so I'm not sure. Maybe Jim B. knows about it.

The pic from TM Tractor isn't close enough to see if the teeth are filed on the corners.

Below is a pic of someone's flywheel and ring gear, you can see the wear on the corners of the teeth from the starter gear engaging the teeth.

[phill_mi]

I composed a post with pictures earlier, but I accidently deleted the post before submitting it and I had to leave to get the engine stand. These are teeth as seen through the starter hole, which seems to be about the same as the gear is rotated.

These are same teeth in above pic, viewed from the right side of fly wheel.

This is taken from below the oil pan/filter area, without rotating the crank, relative to the above pictures.

Notice that the wear indicates the bendix is matting about half of each tooth. There is a bevel on one side of each tooth, in the shiny area, which seems by design. It seems rounded by wear. But there is a gouge worn in the front of each tooth which does not seem to me to be good or original. There are a lot of metal filings on the fly wheel and housing, as well as old black oil. When I get the engine stand setup (a first for me) and remove the picker straps, I thought I would mount the starter and see if I can see what the bendix is doing.

This is a general shot of my splitting setup. My space is limited so I moved the tractor as far back as possible, blocked the wheels, drawbar, and torque tube, and made oak wedges. Then used cherry picker with straps around front and back of engine. I picked up the home made stands used for the torque tub several years ago at a farm auction. I did not realize what they were for until I started researching this issue. I have been using them to prop up 3 pt implements.

[SamsFarm]

You can take the ring gear off of the flywheel, and flip it 180°, then use the other side for the next 70+ years

[Glen]

Hi,
I see in 1 of your pics some of the gear teeth are worn back noticeably, that is probably the reason the starter won't work.
The ring gear needs replacing, or what was said above.

There was a post not long ago about replacing it, you can search for it at the top of the page.
The ring gear has to be heated, so it expands, and becomes loose enough to come off.

The new ring gear has to be heated so it will go on.

[Gary Dotson]

If you simply flip the ring gear, you lose the factory bevel. I guess you could file each tooth to regain it. As far as I know, the available replacement gears do not have the bevel, either, a negative in my book. If I were installing a new one, I would take the time to file the bevel. Some say they work fine without it but I feel it will work better with it. If your ring gear is still good enough to save, I have, on a few occasions, removed the gear, rotate o-deg. and reinstall. Yours may be too far gone, can’t tell from the pics. You don’t need to heat the gear to remove it, just take a hefty punch and tap on it as you move around the flywheel. If you have a freezer, you can use, chill the flywheel for a few hours. If not, you can still get it done. Warm the gear, to be installed, with a torch, 5 or 6 passes around the gear ( hot enough to get it smoking but far from red hot). Pick the gear up with two pliers and drop it in place, making sure it fully seats. It will cool and lock in place.

[Eugene]

viewtopic.php?f=141&p=833455#p833455

Above link. How to replace the ring gear. New ring gear cost me $70-, at that time.

[phill_mi]

Thank you for confirming that my ring gear is worn and for the links. I was not sure how to determine if a new gear (or rotated gear) was needed. When I get the engine on a stand I will be able to start removing stuff and post some more pictures. One of the problems that I first noticed when I got the tractor was the steering shaft was leaking. This subject came up several times as I browsed the forum and learned that the fill plug was vented. Mine was just a plumbing plug painted red, so I drilled holes as indicated in one of the posts that I think Glen posted and changed the oil in the steering box some time ago. I have not used it except to position the tractor prior to splitting. But as I split it I noticed steering oil leaking at the bottom of the bolster. I will check for loose screws, but as other parts have been very worn, I should probably plan to take the steering apart and replace seals. Lots of fun ahead, but I want to stay focused on one or two problems at a time.

[Eugene]

I was not sure how to determine if a new gear (or rotated gear) was needed.

Set the engine on TDC, then rotate the engine via hand crank or fan 90 degrees. Then check the condition.

I ordered the ring gear before I split the tractor. I didn't want to wait 2 weeks for a new ring gear to arrive incase it was completely shot. Turned out that I could have rotated the ring gear 90 degrees as the teeth in that position appeared to be new.

Edit a couple hours later. Sheet metal plate located at the bottom front of bell housing, behind the oil pan. Remove the plate. Engine rotated 90 degrees off of TDC will expose the less used portions of the ring gear.