Bent flex plate while trying to remove main pulley nut

[jangell]

Now that my 2.8L engine is disassembled, I've started taking apart my new(er) 3.0L engine so that I can swap the bottom ends between them. Valve covers came off easily (too easily; they almost fell off once the bolts were out), and even the nuts on the exhaust studs came off without a problem.

The main pulley nut is another story. The new engine didn't include a flex plate or flywheel, so I mounted my 2.8L's flex plate onto the 3.0L. To keep the engine from turning, I put a bolt through one of the holes that the torque converter attaches to, and after hitting the bolt with some penetrant and letting it sit for a couple of hours, I used a 5' iron pipe on the end of my wrench to try to break the nut free.

The first thing this did was break the 3/4" to 1/2" adaptor I was using on my wrench for the 35mm socket. After replacing that with a proper 1/2" wrench, I tried again. After quite a bit of force, the bolt slipped and the engine turned. When I checked the bolt, I found that I'd exerted enough force to bend the hole that I'd run the bolt through in the flex plate.

Now I'm trying to decide if I can use a hammer and anvil to flatten the flex plate, or if I'm going to have to bite the bullet and spend $400 on a new flex plate. Has anyone had any experience with this before?

2600126002260032600426005

As for keeping the engine from turning while I try to get the nut off, I'm planning on buying some some steel stock and drilling three holes in it: two to mount it on two holes on the crank where the flex plate normally mounts, and the third to anchor it where the transmission bell housing attaches to the engine block. I might do a second one for extra redundancy and strength.

I'm curious about using an impact wrench to remove the nut -- the 3.0L "Engine Overhaul Student Reference Book" that I'm using as reference specifically says NOT to use an impact wrench here, but I've seen many post about doing exactly that on this forum for the 2.8L engine. I'd prefer not to hit it with heat, since others have said that you should probably replace the seal if you do that, and I'm trying to take apart only what I need to, and I don't have a seal installer tool (but then maybe I'm overly worried about that).

Thanks!

-- Joe

[David T]

I would carefully hammer it flat but you now have to make sure the ring gear is running true. Try an impact wrench but make sure you have enough compressed air at a high enough pressure so you can let it bang hard enough and long enough. And use a big enough impact, no wimpy 3/8" or harbor freight piece of junk.

[jangell]

I would carefully hammer it flat but you now have to make sure the ring gear is running true. Try an impact wrench but make sure you have enough compressed air at a high enough pressure so you can let it bang hard enough and long enough. And use a big enough impact, no wimpy 3/8" or harbor freight piece of junk.

Unfortunately, I have a fairly basic air compressor (6 CFM), so I might not be have enough air to do anything useful with any impact wrench I can connect to it. On my old 2.8L (before I had the air compressor), I gave up and spent three hours carefully cutting the nut off with a Dremel.

I'll take a close look at the flex plate and see how the ring gear looks. I admit I'm a concerned if it can be safely repaired, or if it might only LOOK repaired but still be unsafe.

Thanks

-- Joe

[TTait]

I picked up an electric impact wrench (Kawasaki?) that works beautifully...

[jangell]

I dug through my stuff and realized I had a cheap 250 ft/lb air impact wrench that I can to get the nut off with. I presume I need to lock the crank from turning before i try to remove the flywheel, right? Or is the hammering nature of the impact wrench such that it's not necessary?

I was going to make that bracket from a piece of flat steel today with my new oxyacetylene kit, but apparently I'm not good with a torch -- I can't even get it to light properly (the acetylene flame as always smokey, no matter how much I adjusted the fuel), there were some popping sounds that worried me when I turned on the oxygen, and I couldn't get it to create a blue flame no matter how much oxygen I threw at it. I must be doing something rather significantly wrong here. I can always fall back to using the bent flex plate to lock the crank if all else fails.

Thanks again!

-- Joe

[Henrik]

Now I'm trying to decide if I can use a hammer and anvil to flatten the flex plate, or if I'm going to have to bite the bullet and spend $400 on a new flex plate. Has anyone had any experience with this before?

I accidentally warped my flexplate while removing the transmission (didn't know to remove it BEFORE you separate the tranny from the motor) so I took it to a good ol' blacksmith who used a huge press to straighten it. I was well aware that it might not work (and the guy pointed out the same) but at $10-20 it was worth it. Sure enough, by the time I got back home the flex plate had reverted back to its warped shape so I had no choice but to buy a new one.

[1batt4u]

I have been selling flywheel lock tools from last year. They work great, so easy!!

http://dmctalk.org/showthread.php?6310-Flywheel-Lock-tool-Easier-way-of-removing-Crankshaft-nut

[jangell]

What's funny is that I remember seeing that thread when I was searching for fixes, but didn't actually READ the thread and realize that you were selling the tool. I'll definitely take one!

-- Joe

[jangell]

Finally got the nut off. I mounted the engine to the transmission again and tried the flywheel lock, but bent it easily due to how tightly the nut was on. I expect that with a properly-tightened nut the tool would have worked just fine.

I tried my weak air impact wrench, but that did nothing. I tried running it both forwards and backwards to no avail.

I tried cutting the nut off with a Dremel. After a couple hours of mangling the nut, I still couldn't weaken it enough to break it free (this is how I got the nut off my 2.8L engine a few years ago). I did manage to cut into some of the threads on the shaft, but no worse than I did on my 2.8L engine, and that held the nut just fine (and I'm definitely not replacing the crank -- it'd be cheaper and easier just to buy another engine).

In the end, I resorted to a MAP torch and resigned myself to replacing the seal in the timing cover. After a couple minutes of heat, the 5' breaker bar, more with the impact wrench, more heat, and the breaker bar again, it finally turned.

Thanks again for all the help!

-- Joe

[David T]

Finally got the nut off. I mounted the engine to the transmission again and tried the flywheel lock, but bent it easily due to how tightly the nut was on. I expect that with a properly-tightened nut the tool would have worked just fine.

I tried my weak air impact wrench, but that did nothing. I tried running it both forwards and backwards to no avail.

I tried cutting the nut off with a Dremel. After a couple hours of mangling the nut, I still couldn't weaken it enough to break it free (this is how I got the nut off my 2.8L engine a few years ago). I did manage to cut into some of the threads on the shaft, but no worse than I did on my 2.8L engine, and that held the nut just fine (and I'm definitely not replacing the crank -- it'd be cheaper and easier just to buy another engine).

In the end, I resorted to a MAP torch and resigned myself to replacing the seal in the timing cover. After a couple minutes of heat, the 5' breaker bar, more with the impact wrench, more heat, and the breaker bar again, it finally turned.

Thanks again for all the help!

-- Joe

Probably put on with threadlocker and when you applied heat you broke it down and then were able to loosen it.

[jangell]

The 3.0L manual did mention thread locker, and said to tap it with a brass hammer to break it free. The hammer had no effect. I did get smoke out the back of the pulley when I heated it (nothing overly thick or anything), and when I got the nut off some oil came out, so I'm guessing I wrecked the seal anyway.

-- Joe