How do you balance a transmission ??
Buy the transmission booklet put out by the MTFCA and follow the instructions.
1. The three triple gears balanced each by them selves so they weigh the same.
2. The brake drum bolted to the driving plate, marked, and balanced as a unit.
3. The main shaft, or gear shaft with the clutch disk drum pressed in place and balanced as a unit.
4. The reverse drum, and low drum balanced by them selves.
5. Flywheel balanced by it's self.
6. Crank by it's self.
And if you want real good results, they should be balanced on a "real" balancing machine... NOT on "a mandrel on knife edges", or on a mandrel on an old grinding wheel balancer.
You can get very good results from the following method; The flywheel should first be balanced bare. The individual magnets should all be checked to make sure they are pretty close to the same weights and then assembled to the flywheel with all their attaching hardware, but not permanently. Then the flywheel should be spun up on the balancer again. This time you swap the position of magnets around until the balance is perfect. This method eliminates any drilling and grinding with the magnets on the flywheel, which eliminates a big potential contamination issue.
Here's one kind of balancing tool. Mike Bender is balancing a crankshaft and flywheel, but the principle is the same. The two straight edges must be absolutely level. If one side of the wheel, or gear, or drum settles to the bottom, that's the heavier side. Some of the weight is drilled out of the heavy side, or weight is added to the light side, until the object is balanced. When it's balanced you can turn it to any position and it will stay there.
Here's a case of adding weight. This transmission drum was so lopsided that we made a weight for it from a piece of brass.
This shows the tool used for balancing the transmission drums. The added weight of the brass was reduced by drilling out material at various places until the drum balanced.
As Ken says, get the book and follow the instructions.
I don't. I don't feel its necessary. Its not a 6000 rpm racing engine. Its a Model T. I have rebuilt 3 engine transmission assemblies and I don't find the level of vibration on any of them to be unpleasant.
Not necessary and a big waste of time!
Here's my balancer.
It is also a really good idea to have all the drums, flywheel, & crankshaft magnafluxed for cracks... Unless you can see the cracks with your eyes, then you can skip magnafluxing and just throw that particular drum away...
Ted, if you could run a full balanced engine, you would change your mind!
Ted,
It May not be "unpleasant" for you....but, what is it doing to your engine and car?
I have a static balancing fixture as shown above and have balanced 5 transmissions as described by Kohnke. From what I have experienced, balancing your transmission can make a much greater difference on how smooth your engine runs compared to having a counter balanced crankshaft.
Out of balanced transmissions cause additional unwanted stress to the crankshaft.
Balancing the transmission is very important....but possibly even more important is making sure the transmission shaft and crankshaft flange also run true.
After carefully balancing the transmission in our 13....the engine still shook. I pulled the engine apart and found the crankshaft flange to have a .0025" run out. Re-faced the flange which corrected that error. Next, found the transmission to be out .007". Replaced the shaft with a straight one and re-assembled the engine. Engine now runs very smooth. I previously balanced the rods and crankshaft.
The engine in our 13 with a stock crank runs just as smooth as an engine that I re-built and balanced having a new Scatt crankshaft.
Get a Message some other way.
The "shaft" that I replaced was the transmission shaft....sorry for any confusion this may have caused.
You would not bubble balance the tire of your car would you? With the technology we have today why would any one static balance it when you can spin them the way they are run in a car????
Agree!
These two pictures are of the final balance of a crank for a customer.I have it balanced to five hundredths of a gram. Not that it has to be anywhere remotely close as this. Doesn't take me any longer to make it two grams or two tenths of a gram. It's because the machine is that precise.
The engine runs that much better/longer because it's balanced and all power goes to wheels.
Has anyone made a "poor Man's " home made dynamic balance set up? If so, any pictures? Joe
How do you go about balancing the flywheel by itself on knife edges? Joe
Joseph asked: "Has anyone made a "poor Man's " home made dynamic balance set up?"
I have.
http://www.antiqueautoranch.com/montana500/septnewsletter/page4.html
Joe: we have a mandrel that we mount the flywheel to and then spin . I'll post pictures tomorrow.
I have used the "poor Man's " home made dynamic balance set up".
It is not very accurate, I just checked the crank shaft with the fly wheel then with the magnet on. I had to correct for 50 grammes.
The magnets themselves can have a difference up to 20 grammes
If you spend a lot of time and effort, the "poor man's balancer" can be very accurate. I balanced the motor I used in my Montana 500 car with it and it runs extremely smooth. Smooth enough that this motor has won four times.
Flywheel is balanced on an arbor and is aligned with tapered cones.
See the amount of depth of metal removed equates to how much out of balance the flywheel was.
J and M Machine,
For a once only, or maybe 2 or 3 times, would mounting the flywheel to the crankshaft to be used, take the place of the special mandrel you have for the flywheel? I have a performance machine shop locally that does beautiful work, but I cannot justify making a mandrel like yours just for my own jobs.
Allan from down under.
Allen, That is the way I have them done, use the triple gears also and mark the weights and gears for location, that way you can move the gears for less drilling.
And if you REALLY want to split hairs, equalize AND spin balance the triple gears before mounting to the flywheel... If one or more triple gears are heavy on one side, you could potentially be out of balance depending upon where the heavier sides stop when the clutch locks them up.
I built a fixture like a couple in here but used ball bearings to ride on the shafts. It worked but not great. I wondered about doing the trans parts individually. Need to look at all the posts carefully. Thanks Guys.
I want to add this engine was a POS when I got it. The whole car was actually. I spent weeks messing with truing the output shaft to the crank and ended up moving it at the flange and repining it to make it run true at the 4th main. The car " I think has a vibration at speeds above 35 MPH . DRIVES ME NUTS
Thinking before this years CAN-AM I will tear it down and figure it out. I am thinking it's now way out of balance at the trans. I balanced the rods , pistons, and crank with the shaft bolted and pinned to the crank.
J and M Machine,
For a once only, or maybe 2 or 3 times, would mounting the flywheel to the crankshaft to be used, take the place of the special mandrel you have for the flywheel? I have a performance machine shop locally that does beautiful work, but I cannot justify making a mandrel like yours just for my own jobs.
Allan from down under.
Allen This mandrel comes with our machine. it is a standard flywheel balancing mandrel nothing specially built just for T's.
I would be almost certain your local shop if they have a balancer would have something just like this one.