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Flywheel lapping


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Lapping my flywheel for the first time.....hopefully last time. I have some lower grit stuff on hand. Not the most course... but course. Do I need to go buy 280 grit for finishing? Or can I get away with only using the course stuff. Thanks in advance.


You’re talking about lapping the taper mating surfaces on the flywheel and crank correct? If so I just use valve grinding compound and seat the flywheel on the crank and lap it a few times then remove reapply compound reseat the flywheel and lap a few times repeat this a few times then call it good.


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Yup that’s what I’m talking. Spin side to side. Rotate completely around on the crank... then wipe off and repeat process til it doesn’t sound gritty?

13 minutes ago, Buckeye513 said:

 


You’re talking about lapping the taper mating surfaces on the flywheel and crank correct? If so I just use valve grinding compound and seat the flywheel on the crank and lap it a few times then remove reapply compound reseat the flywheel and lap a few times repeat this a few times then call it good.


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 Then few rotations 

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Awesome. Thanks for the help. Sheared the key a couple weeks ago. Bought a nearly new flywheel and just want to do it right to avoid it from happening again.


No problem the key doesn’t hold anything it’s simply there to make sure the flywheel is in time. The taper on the flywheel and crank is what holds so you’re doing it right a lot of people think they need to crank down on the retaining nut more and don’t bother with the tapers.


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12 hours ago, Buckeye513 said:

 


No problem the key doesn’t hold anything it’s simply there to make sure the flywheel is in time. The taper on the flywheel and crank is what holds so you’re doing it right a lot of people think they need to crank down on the retaining nut more and don’t bother with the tapers.


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Yea, I know what you mean. Sheared my first one, then a second once I got on it. Crank got a little chewed up right where the threads start. And flywheel taper had some knicks, I just got a new flywheel and needed to clean up the crank the best I could. Everything went pretty smooth. I can’t fire it up til I get my pipes back on (whole different issue). I’m really hoping that lapping it did the trick because I’m terrified that I’ll have to split the cases again and put in a new one. I know that’s worst case scenario but my luck hasn’t been the greatest lately so I’m always on edge about this type of stuff.

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Buy some bluing compound, put a super light coat on the flywheel seating surface ( wear gloves) seat it with the key ways lined up. should be 90% or greater transfer when torqued to spec,

If not lap some, recheck, rinse lather repeat....

https://www.oreillyauto.com/detail/b/permatex-4569/engine-parts---mounts-16774/assembly-lube---valve-compound-17697/161f9b3092dc/permatex-prussian-blue/80038/4610208

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13 hours ago, Toybreaker said:

Buy some bluing compound, put a super light coat on the flywheel seating surface ( wear gloves) seat it with the key ways lined up. should be 90% or greater transfer when torqued to spec,

If not lap some, recheck, rinse lather repeat....

https://www.oreillyauto.com/detail/b/permatex-4569/engine-parts---mounts-16774/assembly-lube---valve-compound-17697/161f9b3092dc/permatex-prussian-blue/80038/4610208

Pardon my lack of knowledge on this, but will the bluing compound affect flywheel removal in the future? I guess I don’t understand how it works. My buddy gave me some locktite retaining compound that is supposed to fill gaps up to .030. He suggested putting it on the flywheel taper before install... no I won’t be using it... it just sounds like asking for issues getting it off in the future. I’m sure it would work great stators never went bad, but that isn’t the world we live in.

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Pardon my lack of knowledge on this, but will the bluing compound affect flywheel removal in the future? I guess I don’t understand how it works. My buddy gave me some locktite retaining compound that is supposed to fill gaps up to .030. He suggested putting it on the flywheel taper before install... no I won’t be using it... it just sounds like asking for issues getting it off in the future. I’m sure it would work great stators never went bad, but that isn’t the world we live in.


Die is simply to check mate between the tapers. If you flywheel is spinning and shearing keys you need to re-mate the tapers though the dye is kind of an overreach or an unnecessary step imo.


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7 hours ago, Larry's Shee said:

Bluing is also known as lay out dye. Don't know if that will help much. Guess he means for even coat? Shit is so thin and dries so fast.

You're looking for a even color on the shaft, that tells you have a uniform surface.

Bluing IS NOT LAYOUT DYE.

 https://www.grainger.com/product/SPRAYON-Layout-Fluid-1D272 <----- layout dye

 

https://www.oreillyauto.com/detail/b/permatex-4569/engine-parts---mounts-16774/assembly-lube---valve-compound-17697/161f9b3092dc/permatex-prussian-blue/80038/4610208  <- bluing

Bluing does not dry

Any fool can hit it with sandpaper, crocus cloth or lapping compound and call it good. To know for sure that you fixed it properly you need to blu check it.

 

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2 hours ago, ClaudeMachining said:

We are using pencils for some year now.

Envoyé de mon SM-G935W8 en utilisant Tapatalk
 

they put graphite in a solution of isopropyl alcohol, it does the same thing.

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