DIY Flywheel Assembly/Truing

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jschmidt425
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DIY Flywheel Assembly/Truing

#1

Post by jschmidt425 »

Hi all, hoping for tips/pointers/guidance/"hell no, don't do this yourself" on reassembling flywheels.

I've seen pics of DIY rigs using gear puller shafts to suspend an assembly and dial indicators to true it, but how feasible is it for someone who's never done this to reliably get it done without someone more experienced over my shoulder? Does anyone who's done it before have any tips to share? I'm not afraid to do it myself and rely on common mechanical sense to not break anything, but I've never done anything quite so precise either.

Anyone in the Colorado area who has done this before want to PM me and find a weekend to help me out? I'd bring lots of beer and gratitude :D
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Re: DIY Flywheel Assembly/Truing

#2

Post by RUBONE »

Flywheels are relatively easy. What sort of tools are at your disposal. A lathe? A truing stand. A couple of cinder blocks? :mrgreen:
RooDog
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Re: DIY Flywheel Assembly/Truing

#3

Post by RooDog »

If you have two centers, a dial indicator, and some mechanical sense, it's no big thing. And I would trust myself more quickly than most any shop.
And when the crank is installed in the cases be sure to do a final check with an indicator in the end of the pinion shaft, ideally you are looking for zero indicated run out,
....RooDog....
PS: Never beat on the flywheels while between centers. Remove the crank and make your adjusting strikes on the bench..... Patience is the key.....
jschmidt425
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Re: DIY Flywheel Assembly/Truing

#4

Post by jschmidt425 »

Thanks RUBONE and RooDog.

To answer RUBONE's question, I don't have a lathe. I have a generic wheel truing stand I was going to drill to hold on to some pointed-tip gear puller shafts to act as centers for the flywheel, along with dial indicators to measure the runout.

I've trued up spoked wheels before - if flywheels is more of the same regarding patience and attention to accuracy then I guess I'm not too worried about it.
chuckthebeatertruck
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Re: DIY Flywheel Assembly/Truing

#5

Post by chuckthebeatertruck »

Unless your wheel stand is either very heavy duty or one of the old Rowe stands, you will not achieve repeatable accuracy. Similarly, it's pretty hard to align dead centers on such a rig. Not impossible, but difficult.

The problem isn't that you can't make it "true" it's that if you remove the wheels, tighten, and reinstall you'll find they've wiggled due to stand flex.

If you don't have bench centers or a lathe, it can be done, but you are fighting yourself the whole way.

As a tip, if you get two parallel c channels and use a press to hold the wheels durning tightening, you often will start out at around .003 off, and mostly splayed.

If you don't feel 100 percent confident you can true below .001 with the tools you have, send it out.

It's not hard to true with good tools, pretty much anyone can do it. Just remember not to bash on keyed shaft sides and to make sure the oiling stays open.
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Re: DIY Flywheel Assembly/Truing

#6

Post by Larry »

I'd like to see the cinder block setup.
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Re: DIY Flywheel Assembly/Truing

#7

Post by RooDog »

In any case, as a side comment, it's good practice to blow out ALL the oiling passages everywhere throughout the engine with compressed air and/or brake clean, to assure none of them are blocked, are clean, and feeding oil. Your oil lines to the tank too, especially if new, or used, Many years ago I discovered a factory oil hole in one of my Shovelhead rockers that was only partially drilled, so be sure to check 'em all out and confirm they are good to go......
....RooDog....
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