Is there any reason not to use a brass Mag Spool to balance the fly wheel?
No I can't see any reason. However balancing a flywheel without the crankshaft is useless if the flywheel is off center of the crank. Most are. Just my 2 cents worth..
Good idea Bob. Agree the flywheel should be balanced with the crank attached configured as it will run in the car. The fellow that balanced my parts balanced the crank by itself then attached the flywheel and balanced the flywheel with the crank attached. He had a dynamic balancing machine. I guess you could do that with a static balancer, I don't know.
I have a grinding wheel balancer like the one that Bob has shown in his picture. I am currently milling a mandrill to hold a flywheel. I had thought that balancing the flywheel and magneto equipment at least statically, my engine would be better off than if it was not. I understand that an offset balanced flywheel would still be a vibration problem. Could a guy just bolt the crankshaft to the flywheel and then balance it together. I would think that the tail shaft of my mandrill would then have to be the same diameter is the main bearing and fashioned as the transmission shaft flange.
OR.... would it be more important to attempt to determine whether or not the crankshaft locating pins are set correctly, so that flywheel is centered correctly? I have no balancing experience and this will be my first attempt.
All in all, I think that a balanced flywheel, even if it is on an slightly offset crank, would be an order of magnitude better than an unbalanced flywheel and mounted on an offset crank. Ideas? Mike
Mike, yes you can balance both separately on a static balancer(single plane) and possibly end up with a smoother running engine. Rotating unbalance is the uneven distribution of mass around an axis of rotation. Mike Bender is correct that the most effective way to balance is as an assembly, using the crank as the axis of rotation on a dynamic balancer (two plane), but I wouldn't hesitate to use just the static ways on the flywheel if that's all I had available. Remember to check the balance of the disc's on the balancer as well as the tooling before balancing the flywheel. Just my humble opinion.
Joe, since I have a friends engine and he is willing, while we are waiting for parts etal, I'm going to experiment with different things, hopefully we will make more improvements than mistakes. Mike
Avoid adding weight to balance, removing the weight is the best option in my opinion since there is no chance of anything coming off, throwing the assembly out of balance and lodging somewhere in the motor. Just my humble opinion.
Sounds good. I have a couple of old unused parts to practice on. We will see. Mike
You cannot balance a crankshaft on a static balancer. Its impossible to eliminate the force couple that is created when you have an unbalance condition that is separated by any appreciable distance. The only reason its possible to balance a flywheel on a static balancer is that the unbalance condition, due to the shape of the flywheel (a narrow disk essentially) cannot create a couple of any magnitude.
Dan, I think this is the first time on this forum that I can recall anyone has recognized that the difference between a static balance (single plane) and a dynamic balance (multiple planes) isn't that one spins the part and the other does not. You can make balancing either very difficult or very easy to understand depending upon your grasp of the fundamentals,
I was thinking, since this is an original crankshaft with no counter weights, whats the sense in balancing it, with or without the flywheel? I was under the impression that the counter weights were to balance out the effects of the rods and pistons. Since I can not do anything about that, maybe I'm best served by just attempting the best balance I can get on the Flywheel? Mike
Mike- yes you can balance the flywheel, but don't use the crankshaft as an arbor if it has not been dynamically balanced, as you will incorrectly correct any crank unbalance using the flywheel, and may well make things worse rather than better.
Flywheel, pistons, connecting rods.
Mike, I do not have a special mandrel to balance a flywheel. I just use two trans shafts, one in one way, the other opposite. They are bolted in place using the usual 4 flywheel to crankshaft bolts.
Seems to work OK. My godson checked the results on their balancing machine on one flywheel, and it needed 7 grams more out of one of my holes.
Allan from down under.
Allan, I do mine the same way on knife edges. I am building engines that run maybe 1500 RPM not race engines. I am not knocking any of the above suggestions. I could not understand how you could balance a T crankshaft when it's all in a flat plane anyway and so skinny, so I don't bother, same with drums. I do try and get the rods and pistons all within few grams of each other.
Mark, mine are done on knife edges too. I made my own by grinding down the back edge of two 14" power hacksaw blades. The rig is adjustable for level. I use folded paper under one end, folding over end over until my level tells me so. Crude, but remarkable effective. I use the same device to balance trans drums, this time on alloy mandrels.
Allan from down under.
Here's one method. Flywheel and crank together.
I learned a few things from using a balance method like the one above
many times. its not as good as a high dollar spin balancer but will do an except able job if you are careful and the rails are straight set up with a good level with an arbor with as little diameter as possible made on a good lathe.
The reason is the small diameter is like a small gear needing very little turning pressure to move on the rails.
As Mike Bender says he is right 10 thou off center from the crank to the fly wheel throws one side of the attempted balance off a bunch.
My arbor has ends that fit through a triple gear the middle is much larger and will hold each drum in place on a transmission in line on one arbor for checking turning each drum in different positions.