New governor assembly for Farmall B

I have a new governor assembly to replace one with some stripped gears. There is no timing mark on the gear of the new assembly, and the alignment of the weight assembly is about a quarter turn different than that of the original. Other than that, the part is pretty much a duplicate and fits fine. But I'm in a quandary as to get it properly aligned, timing-wise, when I put the new one in.

On the front of the governor gear you should see one notch in the gear with two punch marks next to it. This should mesh with a tooth on the cam gear that will also have two punchmarks on the front of the gear. You might have to turn the engine to get the marks on the cam around to where you can see them. Once they're meshed and in place, your valves will be timed correctly.

From there on out it's just mattr of setting up your distributor or mag to get the spark timed right.

When #1 cylinder is @ TDC, the mag drive slot must be HORIZONTAL.

That's all there's to it. ASSUMING the crankshaft-camshaft timing is correct, simply set the engine to #1 TDC, and install the governor so the drive slots winds up horizontal. Simple, eh?

You said you didn't have any timing marks on the new gear. I'd urge you taking a second look for the two punch marks only becaue I had one that ws vry clearly marked. Another one I worked with it didn't seem they put a whole lot of gumption into hittin' the punch and it wasn't easy to see. It might also be worth a look at the back (distributor) side of the gear. If you find a single punch mark there, you likely got a gear for a Cub, and I have no idea whether you could make it work or not.

If they just aren't there, but the gear seems to mesh okay with the cam gear, I'd go at it like this. With the governor gear OUT -- Mark the position of the #1 plug wire on the body of your mag or distributor, pull the cap off, and turn the rotor so that the button points to that mark. On a distributor you can probably do this by turning the button. On a mag you may have to do it from the drive end, turning clockwise.

Bring the motor around to TDC on #1 compression stroke. You should be able to make out the punch marks on the cam gear at this point. Make sure your rotor button is pointing to the mark you made for the #1 firing position, and use the drive lug at the front end as a guide to insert the governor gear so that the notch on back of it meshes with the drive lug. This should get your valve and ignition timing in synch close enough that you can then proceed with the usual drill for timing the mag or distributor.

Just double check before putting thinigs back together that the motor is still at TDC and the rotor button pointing to #1.

HTH

Scotty,

As you know, with a distributor, position of the drive slot @ TDC really doesn't matter, as the distributor can be timed to compensate.

HOWEVER, with a mag, the drive slot needs to be darned close to horizontal @#1 TDC, or there won't be enough adjustment in the mag mounting slots to compensate. Probably better not be more than a tooth off either way of horizontal.

If you have a spare mag, you can see this for yourself. Clamp the bottom of the mag flange in a vise. Then, grab the drive tab with a ViseGrip, and slowly wind up the impulse spring, and note that the impulse trips when the drive tab is horizontal.

This is an almost universal situation, 'most ALL old engines have their mag drive slots horizontal @ #1 TDC.

On the distributor, I agree. Trick is we don't know, and unless Bill set everything up to #1 TDC when he disassembled it, he may not know where the distributor is set to fire next, and I figured it might save him a whole lot of headache to have the rotor pointed at #1 from the gitgo, rather than have to wind the distributor all the way in the event, for example, that it was left ready to fire on #4.

On the mag, I also agree that it trips with the lug just about level across. When I go to remount and time a mag, though, I set it up to hold just before it trips on #1. I might have been clearer on that point in my response to Bill. As a result, the slot on the drive is pointed about 10 o'clock and 4 when viewed from the rear, and the lug on the mag at about 8 o'clock and 2. That way when I roll the mag away to trip the impulse, I only have to bring her around once to #4 to check before tightening her down.

My only aim was to leave Bill set up so that he would be as close as one could expect to having the ignition timed. On the distributor especially, I didn't want to leave him 180 out and scratchin' his head.

He may as well set it up horizontal, then much with the distributor as needed. This will sure save confusion with timing down the road, especially if someone would ever run a mag on it.

You still have the old part? Can you find the mark on it? If so, you can skip all the other rituals and use the old one for a pattern to find where the mark should be on the new one. Ignore the orientation of the weights, they don't matter. Set the old and new next to each other with the magneto drive slots oriented the same. The new one should have the mark in the same position as it is on the old (or 180 degrees away!).

Since everyone is throwing in their comments on which way the mag drive slot should be oriented at TDC, I'll add mine. It should be at about the 2-8 o'clock position, 35 degrees above horizontal, viewed from the rear into the engine.

I'm not sure what there is left to say, Bob. I was thinking ahead.

We don't know where Bill's engine was when he stopped it, or whether he has a mag or battery ignition. More likely a mag, in which case he's gonna have to set it up for #1 anyway. Whichever, we don't know if the distributor or mag is on or off the engine. It's easy enough to set both the motor and ignition up for #1 so as to have the timing close when he puts things back together. It will certainly take less time than trying to troubleshoot an ignition that might be as much 180 out and then having him either taking things back apart (in the case of a mag) or winding a distributor around that far to correct it.

One of the better sets of instructions I've seen a lot around here starts out describing the #1 tower on the cap being at about 2 o'clock. If Bill was to set up with the drive slot horizontal and the ignition (of either type) set to fire on anything other than #1, we'd be three days days and a thirty-post thread that had fallen down to page three getting him straightened out. If we're to be concerned about the next guy workin' on this tractor, my thought is that it's easy and the best thing to do to keep #1 out there around where it usually is.

If the gear is timed up to the cam properly, it makes no difference which kind of ignition he has. They only made one gear to spin the governor and ignition. If the drive slot is in position for one to run right, it's in position for the other.

To my mind, it's easier in both the short and the long run to get to that point by taking the small trouble to get it as close as you can before re-assembly.

I'll be quiet now.

Troubleshooting over the 'net is FUN isn't it, taking hundreds of words to describe what you or I could do in person in a minute or less!

I just LOVE working with this old stuff, trouble is there's not enough around here anymore, an I have to deal with modern ELECTRONIC stuff!

Have a good 'un!

Good idea on matching up to the old gear, and excellent point about the weights! I'd meant to mention the latter . . . To be honest about that, I find it a little surprising that they might have varied in that regard, which is what led me to wonder if Bill might have a gear meant for a Cub. In any event, if it works, it works.

Oh, yeah, here is where the 35 degrees comes from:
http://www.cleancomputes.com/Cub/Cub%20Optional%20Equipment%20Manuals/Battery%20Ignition%20Packages%20for%20Tractors/Page%2003.jpg
http://www.cleancomputes.com/Cub/Cub%20Optional%20Equipment%20Manuals/Battery%20Ignition%20Packages%20for%20Tractors/Page%2004.jpg

Thanks to everybody for the pointers. My tractor uses a mag. I"ve got the timing cover off so I can line up the timing marks. I"ve re-checked the new governor assembly for any suggestion of timing marks. There are none, and none on the backside either.

I put the old gov. gear back in place with all timing marks aligned and marked where the mag. drive slot was oriented (at about 2-8 o"clock looking from the rear). I then removed the old gov. and put the new one in and find that I can get the mag. drive slot to within about a degree of the marks I made. I"m thinking that I can now put the timing marks onto the governor gear and have it in the same position as the original.

I need to mark it since I also have to pull and replace the camshaft gear. Some of the cogs are broken, apparently from the half dozen or so cogs that were wiped out on the governor gear. I also hope to pull and replace the drive shaft timing gear too while I"m at it, though it wasn"t damaged, but is worn (if I can get it off!).

An additional question I have is, since I don"t have the shafts out (and don"t have a gear press), is it permissible to drive the timing gears back onto the shafts, say using a block of wood and light sledge? (Any likely damage to rear seals or something else?)

Thanks again for all the suggestions and pointers. I"ve had old "Short Stack" for almost 40 years, and this has been its first major breakdown.

The thread's gettin' kind of far down. You might want to post the question as a new thread up at the top to generate some more response.

In the meantime, I hope somebody will jump in and say so if this is a bad idea, but I'd think heating the new gears in an oven set at about 200-250 will reduce any pounding you might have to do and might even allow you to drop the gear right on over the shaft and key, and have it shrink back to a good fit as it cools. That's the trick with flywheel ring gears. My only reservation is that the ring gears get used hard but only intermittently. The timing gears are better lubed but work longer at higher temps, and I don't know whether heating them to that kind of temperature would have an adverse effect on their tempering or not. I tend to doubt it, as they're regularly bathed in oil that approaches the lower end of tht temp range. Still, if that might be a problem, I shouldn't think a machine shop wouldn't charge much for pressing gears off and new ones on. If they knew you were coming, it's a quick job that they could do while you wait. I'd think that would be preferable to anything more than the mildest hammering, as anything like walloping it might damage or distort your thrust bearing/limiting surfaces.

I'm afraid you may not be able to get the old gears off without using a press. The heating approach may make new ones a lot easier to get on. If you do any driving to get the camshaft gear on, you will probably pop the freeze plug at the end of the camshaft out of the back of the block.

You may find you are better off in the long run to just pull the camshaft out and get it over with. Depending on the shape of the other gear, the same may be true of the crank gear.

Another thought, following up on Jim's. To replace the crank gear, you're going to have to remove the pulley from the crank to get it and the timing case cover out of the way. If you happen to have a big puller and the head for it to fit around the groove in the pulley it can be done, but it can be a bear and is much easier on a press and less apt to break or ship the pulley. A regular two or three jaw puller will often just bust chips out the edges of the pulley without moving a thing, leaving you to have to replace that, too. That argues for taking it in to have it pressed off, at which point you might as well have the new gears in hand and have them pressed back on while you're there. And I can say for sure that, press or no, heat is a big help in getting the pulley off and back on.

The cam itself comes out pretty easily with bolts you reach through holes in the gear. Removing it does mean lifting your rocker arm assembly to get your push rods out beforehand so that the cam comes out smoothly. Not that much added in work in the context of what you're into already.