Going Backward – Mag Gap Readjust

[Rich Eagle]

It’s disappointing and hard to admit when things don’t work out as you hoped. I spent much of four years putting a 1914 Touring car together out of parts I had collected over 30 years. Since the body panels were far from making perfect I opted to assemble a car that looked like a barn find. It was great fun and most of it was reported on the forum from 2014 to 2018. My attempt to resurrect an old engine didn’t work out as well as previous saves so I ended up sending it to the professionals.
Long story short, I got it running and it ran well. It was not running well on magneto. Somewhere my calculations and various assemblies and disassembly’s to get all the right magnet to coil gaps right had failed me. Having other cars to drive I left it alone for another day.

The day came this spring. Reluctantly I undid all the nice assembly work and pulled the engine out. I will say this is much easier in a ’14 or earlier as the dash comes out and gives easier access. Removing the crankcase I began checking the gaps between magnet clamps and field coils. This resulted in gaps between .021 and .057. I realize that there is some sag in the flywheel and gaps at the top with be greater than gaps at the bottom. Logging numbers at 16 locations and then rotating the flywheel 1/16 turn and re-measuring didn’t yield anything logical. I rotated the engine and took more measurements which led to more confusion.

[Rich Eagle]

Although I had gotten by without for years I made a gap gauge. Taking the field coils off I checked each coil and each magnet. All this with the feeler gauges sticking to the magnets and distorting the reading.

With .007 difference at the magnets and .011 at the coils the right thing to do would have been to get a rewound field coil and remove the magnets. Recharge them and install them all at the same height. Sadly, that delay might exhaust my enthusiasm. With .025 to .040 desired gap I decided to shim the best I could and call it good. It took twice to get the majority of the gaps within the range but it final got real close. The Field coil plate may be bent and maybe the flywheel too.
How did I get by all these years with the other car magnetos working? My hats off to the perfectionists.

Reassembly and installation went with the usual problems. Some went well and some were a pain. Lining up the u-joint was a snap this time. Resting the driveshaft housing on the cross shaft and teetering the engine to the right height let me position the square end with a wire and pry the pan arm back. Presto.
The usual holes never seem to line up without a lot of prying.

[Rich Eagle]

The question of perfection crossed my mind several times throughout this process. I have always tried to get things as clean as possible before assembly or painting etc. On a true barn find is that correct? When real people back in the day worked on these how clean did they get things? My solution was to clean inside or things that didn’t show to perfection. The rest was cleaned enough to handle but no more. These bolts seemed perfectly authentic with some rust on them. They ARE original.

The spark plugs surprised me. I had run less than a tank of gas through the engine since rebuild but they were covered with carbon. 1 and 4 had a pretty thick build up. I suppose this was before the rings seated. One of my favorite plug cleaners is a pill bottle cut to fit the pipe thread and kerosene. 10 or 20 minutes really loosens the carbon. Not much leaks out.

I opted to use a hoist for the dashboard. I ended up doing a little dance removing it.
Hooking up the wiring I noticed the magneto wire terminal was loose on the insulator connection to coil box. Had that been the problem in the first place. Well, I don’t suppose so seeing the gaps weren’t right. After all was said and done the magneto works fine. Even with old magnets and rough looking field coil. When the time comes I can go through all this again I suppose. Or maybe the next guy will.
Rich

[Rich Eagle]

So while I'm at it "Where does the gas come from? The car has developed leaks at the sediment bowl and the carburetor while sitting. I drain the gas tank at the sediment bowl. Each time I step on the running board a 3 second dribble comes out. After a couple dozen times it seems dry. I open the carburetor drain and gas comes out the sediment bowl. It's from the gas line. It can work both ways. Now I can unscrew the sediment bowl. Nope, gas still comes running down my arm. Remember that the sediment bowl can stick up above the level in the gas tank and leave some gas trapped there. Shown in the photo is my gas stop pencil to keep the leaky valve from letting gas through. Sadly the wooden pencil is really made of plastic which melts.

Have a better day.
Rich

[Allan]

Richard, on Henrietta, my barn find 25 buckboard, I have left as much of her accumulated crud undisturbed as possible, resisting the urge to wash parts and scrape off rust. When I had to remove the pan inspection plate to adjust the rod bearings, I had to get a hammer and screwdriver to clean out just enough accumulated grease and dirt to be able to get at the back two bolts.
I was most annoyed when a piece of binder twine caught between the rear spring perch and the backing plate finally disappeared somewhere down the road.
Recently when I lost a tie rod end bolt, a piece of fencing wire was substituted for a missing split pin. I am tempted to leave it like that, as part of her continuing story.

Allan from down under.

[Rich Eagle]

That is a delightful option with all sorts of rewarding possibilities. The crud is a very effective preservative. Even the oil and grease leaked out of my Rusty Coupe have fended off the salt etc on Winter roads. It's not for everyone but a delight to many of us.
Thanks
Rich

[jiminbartow]

The transmission is mainly supported by the 4th bearing. Have you considered sending off your 4th main bearing and drive plate to have the drive plate shaft turned and the 4th main rebabbited to fit the newly turned drive plate shaft? I had mine done in 2010 during my last overhaul and it removed all the sag, as well as stopped the oil from leaking past the 4th bearing out the rear of the engine. I sent mine off to George King III at Engine Restoration in Connecticut, but he has since retired. Jim Patrick

[Rich Eagle]

That is a good point James. My 4th bearing plate was a tight fit with the drive plate to the point cranking was more difficult. This time around I reamed it a thousandth or so and it slides on nicely. It didn't align with the pan bolts upside down but aligned perfectly right side up. Therefore there might be some mis-alignment. I will give that some though, perhaps until something breaks.
Thanks for the thought.
Rich

[jiminbartow]

Since the drive plate shaft fits the 4th bearing fine one way, but does not fit when the bearing is turned 180 degrees may be an indication that the babbit is worn down and the shaft is not precisely centered in the babbited bearing, causing the unsupported transmission to sag, resulting in inconsistent mag coil/magnet gaps as the flywheel revolves and could also result in metal fatigue and eventual catastrophic failure. I considered that the drive plate shaft might be bent, but if that was the case, the shaft would waller badly as the shaft revolved, so I do believe the shaft is true. I still believe that it would be worth the effort to have the shaft turned and centered in the re-babbited 4th bearing so that, no matter which way you installed the bearing, the drive plate shaft would be centered, providing the proper support to your sagging transmission. This would also ensure a more consistent mag coil/magnet gap. Looks like a fun project. Good luck. Jim Patrick

[jiminbartow]

PS. What do you think of the idea of turning the 4th bearing over to the side that it will not line up with the 4 bolt holes, then place a jack under the bearing flange and jack it until the bolt holes line up. This may provide the transmission with the necessary support with the drive plate shaft running on the un-worn surface of the babbit, allowing the transmission to run at a more level position than it was. Jim Patrick.

[jab35]

Richard: I would not force that 4th main. Dan Hatch is practically giving rebabbited ones away, bored undersize to your specifications and no core charge. best, jb

[Rich Eagle]

Thanks for the advice. As I said the 4th bearing slipped on very nicely with the engine upright but that doesn't mean it is perfectly aligned. I assumed it had been rebabbited and reamed undersize. Thus the tight fit on a polished shaft. Also I suspect the crankcase is not true. There are a number of things I would suggest doing on a car that is to be driven a lot of miles.
Grateful for the help.
Rich

[Thorlick]

Rich, I recently went through this and posted some thoughts about how I did it.

https://mtfca.com/phpBB3/viewtopic.php ... 0841#p9084

I eventually discovered a cool hint in a recent Vintage Ford magazine. You can leave the field coil mounting bolts loose after leveling the magnets allowing the mag to jump up against the magnets. Then use the feeler gauges at each of the four bolts to determine how many shims are needed... a huge labor saver!

Finally splurge and buy a new tool. A set of brass feeler gauges (around $4 at NAPA) is a huge labor saver. You can use them around freshly charged magnets with no grief like the ferrous feelers give!

TH

[John kuehn]

It’s always interesting about the different ways folks come up with setting the mag/coil gap.
Rich mentioned the desired gap between .025-.040 gap as mentioned in the manual I believe.
I set the gap on my 3 T’s usually around .030 for an average. I didn’t try to set the magnet/spool height identical around the flywheel. To me the Ford manual setting means that if you wind up with a desired ‘average’ gap around the mag your OK.

[Rich Eagle]

I thinks you are right John. Happily the mag works fine now. At the .021 and .057 it ran on mag but not smooth enough to be comfortable. When all was said and done I had added .010 in shims.

[Mark Gregush]

"gas stop pencil " never done that myself!!

[Rich Eagle]

The short pencils are normally used to plug the overflow tube when adding coolant to the radiator. I recall an eccentric gentleman who used a cellular radiator for a pen and pencil rack. There were dozens sticking out of it. Maybe that's where I got it.