Due to the horror stories about flywheel magnets coming unglued, I decided to dispense with them altogether. Instead, I've machined a 3/4" thick aluminum disk that bolts where the magnet "vee's" were. Permanent magnets will be imbedded around the perimeter face with regular keepers, brass bolts and Loctite.
At this point I'm considering balancing the entire assembly on either knife or roller edges. There is one original balancing hole in the flywheel (a Dodge) already.
The question: Was the factory balance performed on the flywheel alone, or was it balanced with consideration of the crank throws also? If it was done alone it should be fairly easy to balance, but if that existing balance hole was for some other purpose I could mess it up!
Another example of someone negatively influenced by erroneous information.
Just like anything else, if the magnets are properly installed they will never come "unglued".
We must combat the proliferation of misinformation!
Hi George, the factory balancing of the flywheel was done independent of the crank. The flywheel was balanced before magnets were installed. I am with Tim on the magnets. Just check they are not cracked and you'll be fine. If you do use magnets with or without the aluminum disc, balance the flywheel after installing these items. You will probably have to drill the balancing hole(s) in the flywheel on the opposite side of the existing hole or on the OD.
If you need more info, feel free to message me by PM. Good luck.
Thanks guys.........that's the information I needed. I will balance the entire unit at once (my original plan).
Tim, I have no prejudice against the original magnets, honest! One look at the damage they can cause if broken scares the peewaddins out of me though. The advantages of the permanent magnets are lighter weight, greater magnetism for size and VERY long life, as opposed to having to recharge them.
If it'll make you feel any better, this engine's going into a future speedster........so, maybe not so sinful .
Ok, I feel a little better, thanks...
Here's a pretty good older thread on the subject being discussed. And yes, 100 year old parts can come unglued, that's just the nature of the beast.
I re-balance AFTER the magnets are attached when I rebuild transmissions.
Yeah Steve, I'm going to rebalance everything as a unit after assembly also. Just makes good sense.
Somebody no doubt will argue this point, but I believe that one cause of broken magnets is trying to level them by hammering on the clamp plates in an attempt to compress the aluminum spools. That method was fine 100 years ago when everything was only a year or two old, but that is now as obsolete as the repair manuals' telling you to go to the parts window for new parts. Those magnets are a bit brittle to begin with, have gone through a lot after nine or ten decades, and smacking them with a hammer won't soften them any. The aluminum spools (which should never be re-used--replace them!), after soaking for 90-odd years in acidic oil sludge and combustion by-products, are crumbly and weak; not to be trusted in a new engine. Make or buy new ones from brass or aluminum and shim the low magnets to get them on the same plane. Test the magnets for breakage BEFORE assembly, not afterward with a hammer when cracks won't be so evident.
I was somewhat surprised to learn that the flywheel was balanced before the magnets were installed. I can see no way that the assembly could be any better that "not even close" to being in balance by doing this and have proven it many times with my "Snap-On" wheel balancer. On the last engine I rebuilt, I loosened all the inner bolts that clamp the notch of the magnets to the flywheel and gently tapped the heavy side magnets towards the inside and tapped the light side magnets towards the outside of the flywheel until the assembly was in perfect balance, and then re-torqued the inner clamping bolts as well as checked and re-peened the outer brass bolts . The whole process took less than an hour to do as there is enough clearance between the bolt and magnet to move them maybe 1/16" either way (in or out). That particular engine is running very smooth and has been going strong for a few years now. The other advantage of balancing this way is that there are no chips or metal residue created by drilling holes that would be next to impossible to remove totally from the magnet/flywheel assembly.
Or as the tax auditor would say, "Write off!!!"
George,I think it would be nice to see pictures of the finished product and a write up?? Bud in Wheeler,Mi.
Kenneth, that's my intention. Right now I'm looking at the existing flywheel and realized that there's some pretty heavy rust pitting in several spots...enough to affect the balance. So, it's either rebalance it as is or find another non starter flywheel.
The aluminum disk is about finished and is a good, close fit on the flywheel. I have replacement magnet keepers and bolts on order and right now I'm researching the best magnets to use. It looks like the Samarium Cobalt ($) are the best as far as heat tolerance. Each magnet will be in its own hole, two per keeper and secured by Loctite. Fortunately, the spools are brass (bronze) and still measure a consistent .750, so they can be reused.
George, Years ago I static balanced my crank to flywheel had it perfect, then a friend of mine wanted his spun balanced on a computer machine. That engine ran so smooth,I tore mine back out and had it done. The shop drilled four holes an inch in diameter and a half inch deep to balance what I thought was perfect??? That has started a whole lot of engines running smoother these days, right Bud! Just my thoughts since you have it out now. Joe