Separating Generator Section for Ring Gear Replacement

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jwranch
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I have a 25kw liquid cooled machine 2014 QTO2524ANNNA that has a few bad teeth on the ring gear. Occasionally the starter won't engage the flywheel and further grinds the teeth. This moves the the flywheel slightly and then will engage and start on next try. I would like to separate the generator from the engine without damaging anything so the flywheel can be removed and situation remedied. I am hoping the ring gear can be heated to expand and remove, then heat ring gear, cool flywheel to reinstall flipped to get the other "new" side of ring gear to engage the starter drive. I have downloaded the service manual for this unit but it doesn't show how to properly separate the generator. Based on schematic, can the four bolts from the flex plate to the flywheel/fan be removed after the starter is removed, then remove the 4 long bolts to take the generator off as a complete unit? If so, I assume I would need to support the engine end of the rotor assembly through the cooling slots in some manner.

If someone can shed some light on this for me, it would be greatly appreciated.

Regards,
Jwranch
jwranch
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Several have reviewed this post, but no replies yet. If someone who has separated the generator section from the 2.4l mitsubishi engine will opine or will point out a link to a reference document that covers this operation, that would be greatly appreciated.

Best Regards.
stefuel
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Sorry, I can't help as I've never done it before. That said, I downloaded your owners manual and looked at the parts blowup. It doesn't look that complicated.
I also noticed that it doesn't list the ring gear separately, only as a unit for close to a thousand dollars. OUCH...
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jwranch
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Yes, I saw that price tag as well. I am hoping that it a typical ring gear that is machined separately like many that can be removed and reinstalled by heating ring/cooling flywheel. It is attached to a cast flywheel that has the cooling fins so must not be one part. The problem teeth are not missing, but just ground and rounded off on the engagement side. If necessary, I can replace the whole assembly. From the drawing do you think you can unbolt the flywheel from the flex plate (4 bolts), then remove the entire generator section?

Regards,
Bob
Chris
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I don't know if there's a document on this or not? If there is, I haven't seen it...

I've never removed a ring gear from a Generac unit, so I can't speak to that, but I have pulled a few rotors out before and it's not difficult with the right tools.

The starter gets removed and will reveal the flywheel to flex plate bolts which get removed one by one as you bar the engine around. After that, the stator hardware can be removed and the assembly can be pulled away. Some flex plates had silicone on them where the flywheel meets up, so you may encounter that. You'll have to support the rotor the best you can because it will be rubbing on the stator once you remove it. The assembly will drop to the bottom of the stator and weighs quite a bit with the flywheel attached...

The 2.4L engine used a special bolt pattern on the crank, so the flex plate can only line back up one way should you remove that from the engine for some reason.
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jwranch
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Chris, that information is very helpful. I was thinking of using one or two nylon straps to go through the cooling slots in the outer barrel and around the rotor shaft to keep it more centered and hopefully keep the unsupported weight from damaging anything. That is good to know on the bolt pattern as I thought maybe rotating it one bolt hole would be helpful but that won't be an option. I'll report back on findings when I get this done.
PhilD13
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If you get the alternator separated from the engine then you should be able to heat the ring gear and slip it off the flywheel and turn it around. Another ring gear would cost about 110.00 or so from a parts house or maybe through your local car mechanic. It's basically just a Mitsubishi turbo 2.4L stationary engine.

I think you are on the right track with separating the two, though I have never had to do it. The trick is to provide enough support and lift to the stator to lift and support the rotor just enough so you can remove the last bolt or two from the flex plate without damaging the plate. One of those scissor type car jacks may slip under the stator and provide the lift needed.
jwranch
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So as an update, I separated engine and generator by taking out the 4 bolts accessed through starter hole connecting flex plate to flywheel/fan. After removing last bolt, I looped nylon ratchet strap around a cooling fin on flywheel trough the topmost cooling slot in the barrel and took weight of the rotor. My unit had a small amount of black silicon as Chris mentioned between the flex plate and flywheel but was easily sheared free by rotating engine with generator held stationary by the nylon strap. Note the flex plate fits inside a machined lip on the generator flywheel so it doesn't need supported until you start to separate the two sections.

I removed the two engine mounting bolts and the two generator section mounting bolts (bottom ones through rubber isolators). I then lifted the generator by lifting eye and blocked under the bell housing so generator feet would clear the rear cross member. At this point I removed the nuts from the rear of the four long through bolts and slid the generator off the back. This revealed the damaged ring gear and flywheel/fan. I heated the ring gear with Acetylene torch but wasn't able to get it to expand enough to slip off without making 4 special clamps to basically pry off using the 4 threaded holes for the flex plate bolts (see pics I will try to post). This was successful and then rotated the ring gear and reinstalled. Installation worked great by heating the ring gear in the oven to 450F for 30 minutes and cooling the flywheel with a plastic bag of ice cubes. It was loose on the flywheel for several seconds until it cooled and locked in place.

It went back together without difficulty in reverse fashion. I did put a bit more silicone between the flex plate and flywheel like was there as thought must be reason for it (keep flex plate from ringing???).

Notes: I had engine/generator skid on a trailer and lifted with come along attached to two post auto lift. I was then able to roll the trailer away to separate. That worked well, but you can work with what you have to accomplish similar task. Also, the four special clamps I made did the trick. I was concerned getting too wild with the torch with the flywheel on the generator shaft for a couple reasons (damaging the windings that went behind the flywheel or altering the ring gear metallurgy). I did try to pull the flywheel off with a large puller but it didn't come loose without concern of breaking the cast flywheel so I quit trying that and resorted to making the four special clamps.

Special thanks to Chris and Phil for your help. This site is great.
jwranch
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stefuel
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So it's back together and starting normally? :bigsmile:
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