Jockey Journal Forum banner

balancing hd flywheels at home

40K views 25 replies 14 participants last post by  concrete guy 
#1 ·
some of you may have seen this before, some maybe not. i am a back yard builder and don't run a shop of any kind. i do want to do all i can at home and do it with the simple tools i have. i do hd flywheels so that's what i gathered tooling for. an S&S master balance kit is costly but so is having many sets balanced by some one else. i got the kit and it has paid for it's self in a few ways, each balance job i do the cost goes down and for me the key was i learned a new trick.
basic tools needed...
a balance kit that works with the flywheels you will be working with.
scales that will weigh in tenths of grams up to around 2000 grams.
a level surface plate is nice but any flat, hard level surface will work.
a drill press that can be run slow and bore up to half inch diameter in hard steel.
an old lathe is handy but is not a must have.
past that, it takes nothing more than time and simple math.
i start by making sure all parts to be used fit. you don't want to weigh, balance and then find out the replacement connecting rods crash into the flywheels. test fit every thing for the needed clearances first.
on this set of 68 FLH flywheels i used S&S replacement rods. the rods have larger beams and contacted the drive side flywheel. i mounted the drive side flywheel on a junk shaft and clamped it in a 4 jaw chuck and trued how it spun. with a light shave on the inside of the wheel i had the needed clearance (0.060" is as good as a mile)
shaving the wheel on an old south bend...


i did use the tail stock and center to steady the wheel while cutting, just slid it back for the pic. if you don't have a lathe, an angle grinder could work with much skill.

next is to weigh all that slips and slides. i start with the pistons. well i forgot to take a pic of pistons but well... next is to weigh each ring set, you did check the ring gaps in the bores first right?...


next is rods, rollers, roller cages, crank pin, nuts...




lots more to come...
 
See less See more
4
#3 ·
and...


a total weight for each rod is needed, here's the front rod...


then you must weigh each end of both rods. here are a few tricks i have learned the hard way. i use a string for hanging the rod level while weighing the other end. for me the longer the string, the easier it was to get accurate weigh measurements. i start by locating the scales with a plum bob so the string hangs level and the other end of the rod is very close to cenetered on the scales...


once the scales are located, hang the rod on the string and adjust the strings length so the rod beam is level with the scales balanced. it will take some time to do this, be sure to check closely as you go...




after weighing each end of a rod, does it add up to the total weight you recorded before? if not, weigh each end again and again and again untill they stack up within a few grams of the total.

more...
 
#5 ·
should have said this before. look for anything on the rods surface where it will rest on the scales, lomps and other knobs will screw up accuracy, pick the smoothest surface to rest on the scales.
weigh the wrist pin end of the rear rod...



to weigh a rear rod crank pin end, i place them on the scales in this direction, open side down...


then it's time to do the math. i do wheels at 58% but many will have their own preferance. most go with 60%...



once the bob weight amount is known, build it with shims, washers and i like to use full wraps of masking tape to fine tune for the exact amount...



more...
 
#6 ·
with the bob weight amount know and built up, mount it in a wheel and see where the heavy spot falls. this the drive side wheel...


and the pinion side wheel...


you will note both wheels ended with the crank pin area heavy. i hate the though of drilling cast iron that spins in a stressed area... like a crank pin area. these wheels had been factory balanced and the drilled holes ended up in a lighter weight area, cool... i will test what effect adding weight in the un needed holes by poking bolts or whatever in the holes will do...


and...


cool, some added weight will get the crank pin area off the bottom.

more...
 
#8 ·
at this point i have no clue of the exact amount that is needed or how much will be gained by filling one hole at a time. how and what you fill the un needed holes with will make a big difference. heavy metal called malory metal it tungston (old used up end mill shanks) will stack on the weight quicker than a steel or lead slug. these wheels didn't need a large amount so i tap the holes 1/2"X13, pour lead to within 1/4" of the top and loctite a steel bolt in to trap the lead...


and...


i do one hole at a time and check with the wheel on the stand if more weight is needed. i ended up plugging all factory drilled holes in these. not every set will need all or even some of factory holes plugged.

here you can see the effect of plugging three holes had, the crank pin swung up away from the bottom, heavy spot...


now and then with filling factory balance holes the cheap way i do them, lead and loctited in and sawn off bolts, the crank pin area will still be at the heavy spot. this wheel was very close so some simple die grinder work that basicly cleaned the casting was enough...


a bit more...
 
#9 ·
these wheels balanced by plugging the factory holes and with slight drilling on one and a slight die grinder shave on the other...


if you have wondered if you could do your own balance work at home, you have just seen how simple it can be to static balance. yes, the first set will be a chore untill you get a feel for how much drilling is needed at the heavy spots. the more sets you balance, the quicker and easier it will be. collect some tools, add to your skills, have a smooth ride...
 
#16 ·
on a second thought...
magnets should be kept away from inside engine parts. if anything should get magnitized, oil will not flush away minor metal particles. itty bitty bits of hard material stuck inside can be a quick death for an engine.
maybe if everything is de magnatized after...
 
#24 ·
Good post Dan. I tried hanging my rods with string and just could never get repeatable measurements. There is definitely an art to that. I got frustrated enough I just built an adjustable stand with bushing and bearings.





I opted for truing wheels because there are so many other things I can do with this stand besides truing flywheels. I don't know how to embed vids but here is a shot

 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top