I went through something similar. I was advised not to reuse my flywheel since I have a RHD Moke and I was still in the child bearing bussiness - lol

A lightweight flywheel will do wonders to your acceleration and is a noticable difference.

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As the lasy guy suggested, if the crank is ok, I'd simply put that flywheel in the scrap pile.

Loads of guys on here will have a good used flywheel and backplate they'll happily sell you, or you can buy a new one for the piece of mind. A nice lightweight steel flywheel will also make the engine rev a little more freely.

That is two votes for not reusing the flywheel, so I am now looking for a replacement. If anyone has a good used one please let me know.

Any thoughts on resurfacing the pressure plate?

Mate for your own safety, I would be finding another flywheel, or at least cracktesting this one if it's all you can get.

Heating grey cast iron (which is what this flywheel is) to red heat can cause cracking, it also causes hard spots in the casting due to rapid cooling. Plus, it's already stripped one stud hole..
Over here I'd just pull another one off the pile in the corner, but I do appreciate they are rarer there. IMO the earlier ones with their bolted in steel centre will take more abuse without damage.

Thanks for all the replies.

While passing through my garage I thought I would try the impact wrench again. The bolt tightened a fair amount, stopped, and after letting it hammer for a while undramtically popped loose. I did have the flywheel wired to the housing, so maybe that prevented drama.

I am tempted to reuse the flywheel. I don't think the peripheral of the flywheel ever got hot enough to change material properties and I am guessing the material properties of the center hub section aren't that imortant. A concern would be the keyway area has been changed, but I am not sure that matters much. Based off my experience I am assuming most or all of the torque is transmitted through the taper fit. I was thinking about getting the flywheel balanced becuase of the chunk I took out. I am assuming it would be good to get the clutch area resurfaced as well.

I am not sure what to do with the pressure plate. Having never seen Mini clutch parts before I was expecting the friction surface of the flywheel and pressure plate to have similar looking wear. From the third picture it would appear most of the slipping occurs on the flywheel. Is this normal? Do I need to resurface the pressure plate as well? If I do will I be able to find anyone that can do it (Madison, WI area)?

I had bought a second Mini earlier this year so had started this work to fix an oil leak to sell the car. So, I would like to spend the least amount of money possible without doing something that would cause the future owner grief. Any chance just a new clutch disc and scuffing up the friction sufaces on the metal parts would be sufficient?

The upper left bolt is where the chunk of flywheel came out on my first attempt.

Melted portion of clutch. This could have been what I saw when I thought the friction material was burning.

Friction surface of flywheel versus pressure plate.

This can be very hard when the flywheel welds itself to the crank.  In these instances, the massively overbuilt home made pullers or the original Churchill or Sykes Pickavant professional tools come into their own.  

At this point, use two or three short chunks of chain to fasten the flywheel to the housing, so that when it breaks free it doesn't fly across the room and wreck stuff.  Like your fingers and shins...

Personally, I like hitting things with godlike blows from massive hammers, though I do now see how it can cause permanent damage to the center main bearing.  In my youth, I never caused those sorts of damages though, and have removed a couple of epically fretted flywheels.  This is usually part of discovering that the incredible 130+ hp race engine your pal paid big dollars for is really just a core.

So, I have had the center bolt of my puller as tight as I could get it with a six foot snipe on a breaker bar.  I think at that time it was a 15/16" fine thread affair, and now it is 1".  It presses on a piece of steel machined to fit in the crank via a ball bearing.  On one memorable bad flywheel experience, I could tighten it that tight, wallop it, tighten more, and so on and watch it slowly move.  It was actually pulling metal off of the tail of the crank and out of the flywheel.  Very messy.

I do doubt that the penetrating oil is doing anything.  I would imagine that the use of a refrigerant might be very effective; though I have never done that.

As for the heat, I doubt you will want to use the flywheel again, and I also doubt you are hurting the crank.

Still no luck. I have been heating the hub section of the flywheel (with the puller installed) everyday with oxy-acetylene, each day a little hotter. I had my wife try to hold the engine to see if I could get the puller tighter twith a breaker bar and found I would need to bolt the engine to something or have someone much larger try to hold the engine. I had her run the impact wrench while I heated hoping the impact wrench blows/vibration would help.

Today I heated it until portions of the hub of the flywheel were red hot. It got hot enough that the clutch set on fire. I followed this with the impact wrench and hammer blows. The puller bolt tightened some, but it is still stuck. I then poured water on it.

I have also been spraying the joint with Kroil.

I am not sure what to do next. I don't know if I should give up and try to cut it off. I also don't know what other heat related damage I may have caused to other engine parts.

Heat it up and then cool it with ice or maybe spray it with freon that's a bit pricey but quick.

I have a special tool for stuck parts when I need to heat them up.

//www.youtube.com/watch?v=_YO_snrzYrs

I made three attempts with increasing heat from the oxy-acetylene torch and no luck. I was able to get the puller center bolt a little tighter, but I am not sure if this is accomplishing much. The puller is no longer flat (assuming it was when I bought it). I may need to build a stronger puller or buy one if anyone has any ideas where one can be bought.

The last person to take this apart aparently used enough heat to locally melt the flywheel. There is a groove that appears to be cut in by melting across the top of the center hub section. I was hoping that wasn't going to be sign of how hard this was going to be.

These days I just use an electric heat gun and a puller. A little heat makes it come apart so much easier, I don't know why I didn't do it thirty years sooner.

Leave the hammer in the toolbox it is not needed for this job.

No disrespect meant.

The flywheel bolt and the keyed washer have been removed.

That's a good one did you remove the center bolt, LOL the puller will break then for sure. Trouble is the pullers are crap and the bolts supplied with them are even worse. I made my own puller out of a 1" thick piece of solid steel and use only grade 8 bolts in it. An old main bearing shell in the flywheel ring gear holds the engine from turning perfectly and I use a front damper bolt threaded in where the flywheel bolt came out of, to put the puller against. Remove the diaphram totally if you haven't then do it. Get some grade 8 bolts for the puller to flywheel. Tighten it down with the breaker bar. Take the Torch and heat around the center till you see the metal sweat. then quickly tighten the center bolt a little more and hit with a good 1 1/2 lb hammer and it should pop right off. They do have a bad habit of welding themselves to the flywheel every once in a while and iif it did without have my before mentioned homemade puller you're beat. You'll break the cheapy ones they sell now. The factory one which I got a hold of after I made mine is a huge heavy industrial one. So that will give you an idea how problematic these can be if the factory made a huge one for this job.....

Just to ask the dumb question - Did you remove the center bolt?

I decided to helicoil the bolt. I tookthe diaphragm spring cover off to have better access to the flywheel and saw I pulled a small chunk of flywheel out when the hole let go.

The helicoil I put in seems to be holding. I have the puller on about as tight as I can get it with a 1/2" breaker bar. This is with a combination of the engine supported on the ground and from above with the engine hoist. The fixturing isn't the greatest, so I could probably get it tighter if I supported the engine better or had a helper hold it, but I am afraid of pulling out another bolt.

I have been hammering on the center puller bolt, tapping on the back of the flywheel through the starter hole, spraying kroil penetrant on the mating surface between the crank and flywheel and have heated the flywheel around the crank with a propane torch. There is no sign of it moving. It looks like I may be bending the puller. I have been avoiding using a hotter torch (oxy acetylene) so I don't damage heat treats of parts. Is there anything else I should try, or do I just need more heat?

If I didn't mention it before this is a pre-verto clutch.

You can drill the flywheel and tap new threads in a larger size, and use an appropriate bolt for the new threads.

You can do the other two at the same time if you like.

A critical part of pulling the flywheel is getting the puller square to the flywheel.  This is where identical bolts screwed in the same distance is very handy.

I was attempting to remove my pre-verto flywheel today. I started with tightening the puller with a breaker bar and hitting the end of the center puller bolt with a hammer. When this didn't work and I was hacing a hard time getting the bolt tighter I got out an impact wrench. This appeared to be slowly turning the bolt. Unfortunately one of the three bolts that goes into the flywheel pulled out and flew into in my finger. The threads in the flywheel at this bolt weren't in the best condition to start with. I had a hard time getting this one started.

So, I now have a flywheel that has been very difficult to break free (key washer had been removed) and I can no longer attach the puller. Any ideas on how to proceed? Would a helicoil potentially work, or would this be too weak?