Pulling the flywheel

[samo_ott]

Re: Pulling the flywheel

Experience. Grade 5 bolts get their threads stripped off. Grade 8 bolts don't.

I agree with that as I had it happen to me recently but it still doesn't make sense that the aluminum threads are stronger than grade 5 steel.

 

[cc67]

Re: Pulling the flywheel

+1 on the impact, just a little at a time. I have never have had to beat on the crank to get a flywheel to pop off.

 

[BillP]

Re: Pulling the flywheel

Absolutely not so ... try magnetizing a piece of steel and heating it. It's gone forever! The magnetism is permanently gone unless you apply a strong, properly aligned aligned EMF.

Absolutely...but put that statement into perspective with what we are doing here. Magnetic damage happens when the specific currie point (temp) is met. Currie temps on ob flywheel magnets are probably closer to 700F than less. Heating a flywheel hot to touch for expansion is around 200F. Low tech OB flywheel magnets are made to operate in these temps. All magnets regain their strength after cooling if temps stay under their currie point. I do agree with you however, that a person shouldn't heat a flywheel if he doesn't understand the limitations. On the otherhand, if he doesn't understand the limitations of damage by rapping on the puller he shouldn't do that either.

bp

 

[jonesg]

Re: Pulling the flywheel

Agree with Wombat, I use an elec impact wrench to get stuck parts moving, they don't impart a ton of direct force, its more of a shock thing.
I almost bent a 24 inch breaker bar trying to get rusted lugnuts off the trailer, put the impact driver on it and let it bang away for 10 seconds and the nuts slowly start moving, its the shock, not the force.

Same idea when rapping the centre bolt on a puller, if you worry about damaging the main bearings/seals then you have the wrong idea,
rap (aka heavy tap) with hammer to induce shock, don't belt the daylights out of it with a BFH.

 

[BillP]

Re: Pulling the flywheel

I agree with that as I had it happen to me recently but it still doesn't make sense that the aluminum threads are stronger than grade 5 steel.

It depends on the grade of aluminum and/or whether it's anodized. I don't know what grade ob flywheels are but I do know from gun stuff that the aluminum (if memory is right it's 2021) used on receivers has a Rockwell of 60-80 and the same receiver in steel has a rockwell of about 35-40. So the alum can be much harder.

 

[Jerry81C]

Re: Pulling the flywheel

Heat or no heat....What has worked for me is PB-B let it set over night at the same time freeze a soda bottle filled with water. Prior to setting up the puller heat just the shaft with a hand bottle cut the plastic from the bottom and cool the shaft fast works wonders and there is no banging. I do agree tighten the puller wait tighten more sooner or later it will let go.