trouble removing flywheel

[benissimo]

New to cars (about a year). Had to change clutch on my 2008 sentra 2.0S MR20DE. Pulled engine and transaxle as per service manual. Now I'd like to do some preventative maintenance on the engine while it's out (any suggestions of items to address are welcome). My problem, however, comes in getting the engine off the hoist and onto a stand. Removed pressure plate and clutch disc. After that you can see the drive plate (not sure this is what it's called) and the flywheel. These are mounted onto shaft with 6 torx bolts. I stripped 2 of them severely. Where I was successful removing these bolts, I could see the holes of the "drive plate" are not threaded, while the holes in the flywheel are. Does this mean I can drill the heads off the stripped bolts and the drive plate will come free? Or is the drive plate attached to the flywheel somehow? I ask because the service manual, nor anything else I can find, makes any mention of the drive plate. If I look up my flywheel online I see that the drive plate is sold with it, and it is called a dual mass flywheel.

Anyway, if drive plate is a separate entity from flywheel, drilling off bolt heads would free drive plate. After removing it would leave me enough bolt sticking out to grab with a wrench and finish getting out the flywheel.

Dont want to do something I'll regret, so any information is greatly appreciated.

[centralcoaster33]

Drive plate? What "Service Manual" are you using please? I'm curious.

As far as what's in the Factory Service Manual, you have a Clutch Disc, Clutch Cover and Flywheel. (no fourth piece). Is there a chance you have an aftermarket flywheel, like a Fidanza? Those have replaceable friction surfaces, but those are held on with like 16 or more screws/ bolts. Here is a link to the FSM CL chapter:
http://www.nicoclub.com/service-manual? ... _Sentra/cl

Here's a link to the whole thing (you can save these PDF files to your device):
http://www.nicoclub.com/FSM/Sentra/2008_Sentra/

The Flywheel itself should come off after 6 bolts are removed. You want to replace those flywheel bolts with brand new ones. You want to get your Flywheel resurfaced and balanced.

While you have the flywheel out of the way, I think you can replace the engine seal at the output shaft. While you have the entire engine out, you can clean up the carbon buildup in your intake system, replace hard to reach rubber hoses for vacuum and such, clean valves (auxiliary idle, egr, or whatever, I don't know that newer cars have so many of these). You can review and address any oil leaks pretty easy with it out, like check the oil pan seal, if it leaks, now's the time to remove and reseal that.

Welcome to NICO! Enjoy working on your car. Be sure to call a local shop and get a quote for a new clutch installation. Then you can pat yourself on the back with all the money you saved and new tools you own!

PS - I'd like to move this thread to the more active and applicable Sentra Forum. Do you object?

[benissimo]

Hey, thanks for the input! I wholeheartedly agree to move this to sentra page- didn't see it when I started. I also don't know how to move the post. If you can, please feel free.

The flyhwheel is OE by LuK. I would post a link to the part but it says I'm not allowed. It does not look like other flywheels that show up when browsing the internet.

You know the brake rotor-like disc inside the pressure plate? There is one of those on the flywheel. That's what I'm talking about when I say drive plate, don't even know where I got the term. Wondering if its a separate piece or if it is all one assembly with the flywheel.

I am using the FSM from this site. It just assumes you're not an idiot and have proper tools to get some stupid bolts out without stripping them.

[benissimo]

Flywheel listed as LuK DMF100 dual mass flywheel

[centralcoaster33]

Okay, that's the friction surface of the flywheel. Try not to take apart the flywheel, just remove it. Only the six bolts in the center hold it on. You can not safely drill or cut those off to my knowledge...

How's it coming along?

[benissimo]

Well, not really coming along at all. Not room to get after these bolts with some stripped bolt sockets (they are recessed down inside the friction surface).

Tried to drill into the bolt to set a screw extractor. After wasting 20 bucks of bits found out I wasn't going to make any progress. Even tried masonry bits with the hammer drill. Nothing.

Only thing left I can think of- I've got some sockets around 8-10 mm, I can fit them in the stripped bolt heads. Going to try and weld them onto the bolts and get hold of them that way. Last thing I could think of before paying someone to help. Thanks for moving this to the sentra page!

[centralcoaster33]

Can you post up some photos of the bolts, flywheel, damaged heads, etc? I'm not sure you can drill into those bolts, I think you've found out the answer is no! I wonder if you're having at the correct bolts. I also wonder if I (or others) can help with bolt extraction ideas. I'd like to see what access you have and what the holes look like and the messed up heads. Thanks. A far photo, closer and close up would be super helpful.

[centralcoaster33]

Scratch that, I just found this video...
https://www.youtube.com/watch?v=F0ke9VWmhUw

I see what you are working with. I wonder if you used torx plus and still stripped them. I would say there is no way you want to drill into those. Cutting them off, maybe, but you might damage the flywheel (which I guess you'll be replacing anyway) and you'll still have to extract the bolt. If you drill beyond the bolt, then you are into the driveshaft or the threads and you really don't want to mess that part up. You may have to haul it off to a shop. Maybe take the photos and bring those to a mechanic and see what he would charge before loading up the engine.

Hmmm, well maybe post a close up photo of the damaged bolts... I guess that could still be helpful.

Ooh, Ooh, I have one idea that may or may not work. Sometimes, when I've messed up or stripped a head, usually a phillips or allen wrench head, then I take a cutter and cut a groove across the entire head. Then I stuff a flat head in there and unscrew it. Perhaps you can use that approach?

[benissimo]

Oh I found the right bolts alright. Ate a bunch of drillbits finding out that NO- you kinda can't drill on those bolts. Except you can if you have an a big hammer drill (not the little ones, the big ones that are essentially a small jackhammer that also drills).

I decided my flywheel was toast (due to impatience) so i drilled out all 6 rivets holding in the friction surface. Took that off. Now there is still the part with all the vibration dampener business inside. That is bolted in with the flywheel by the 6 flywheel bolts in the center.

If I drill the 2 stripped heads off now, I think I can remove the vibration dampener part (those holes are not threaded, whereas the holes of the ring gear are). That way, I think I'd have enough bolt shaft left to get a pipe wrench on it. Or actually have space the weld a nut on the end. At this point I'm still not getting into any threads I can't replace, so I don't see what it could hurt. I might try cutting the slot for flathead, but these things are really stuck. Does that work for you when the bolts are really stuck? I used my 18" breaker bar with a 2 ft cheater pipe.

Side note- as far as I could tell, the flywheel bolts are not torx plus. T55 fit, TP55 did not. Probably didn't help that the best way I could keep the whole thing from spinning was to put a box wrench on the crank pulley and lower my hoist where that wrench would be stuck on a cinder block.

I guess I'm going to read the post on image posting. Cause I can't figure it out

[centralcoaster33]

When I did my clutch, I countered the shaft with a socket on the crank pulley. Pretty typical. Though I don't have to pull my engine to do such work (240sx).

You method of tearing off everything as you work your way down to the bolts seems reasonable to me. As must as cutting grooves goes, that has been on smaller scale screws and bolts for me, not these big ones. You'd need some sort of big flathead to turn them. It works in some situations and not in others. Welding a nut on might work, or a stud extractor if you get the head off clean and still have some bolt exposed. Lot's of soaking to PB-Blaster when you're not wrenching on it.

Anyway, get your photo onto a photo sharing/ hosting website. Get the links that website provides for embedding and copy it to your clipboard. Most sites have 3 or 4 types of links to use and they each have different results when viewed online. In the forum post, use full editor and preview, click the Img button, paste your link between the two Img boxes. Do a preview before you submit it.

[benissimo]

[benissimo]

Yes, I am grateful for the photobucket tutorial on this site!

[benissimo]

First photo was flywheel pre-destruction.
Here you can see I drilled out the rivets holding the friction surface on. Removed friction surface. What's left is this and the ring gear behind it.

[benissimo]

Anyway, you can see the 2 remaining flywheel bolts going around the shaft in the center. Those are the stripped ones. Was trying to finished cutting the heads off (they are quite pesky) and wore out my bits. Back to the store.

I'll admit freely I got fed up enough that I was willing to pay someone. Talked to a couple shops listed as automotive machine shops, and they basically said they don't normally take a whole engine to work on something like that. Also told me after the heads come off the whole flywheel should be free. Says the heads are the only thing holding it on. I don't really believe that. Its clear I can remove this next layer to get down to just the ring gear. However I believe the holes in the ring gear are threaded. Anyway, hoping if I can get this next layer off there will be some exposed bolt shaft. Will send another picture of the bolt holes so you can see, but my camera sucks so it might not help

[benissimo]

[centralcoaster33]

Hey, nice work. You're making progress! They are correct, nothing else holds it on. Those holes aren't threaded either (that just wouldn't work for mounting a flywheel flush to a crankshaft anyway). I can see they aren't threaded in your photo of the holes where the bolt is missing.

So, time to get tappy with the hammer I think. It should be able to be knocked free and pulled off. The hub center will be pretty snug on the crankshaft and there should be a pin between the two that would essentially keep them aligned with eachother, so don't try to "twist" it off.

Maybe you can put pressure on the flywheel by wedging something between it and the engine block. Then, while it's under that stress and pressure, you can tap on the other side or same side to free it.

Now, as you are drilling out or grinding off those heads, the bolt remnants are probably flaring out a bit, making a small mushroomed lip that the flywheel has to get past. I think that and the usual binding of parts is all you're dealing with now. The real task will be removing those bolt remnants after you get the flywheel off I think.

[benissimo]

Thanks again. I agree with you. Going to hit it again tonight. Let you know what happens. And hopefully, those bolt remnants are nothing a cheater pipe cant handle

[centralcoaster33]

Any progress?

[benissimo]

Yes!

I got the heads drilled off. Thing still wouldn't budge. Turns out the bolts flared out so much they were stuck in the flywheel bolt holes. Had to drill all the way through them. After that though, the flywheel fell off and the bolt remnants twisted out by hand. No thread damage anywhere.

Definitely went through about 30 bucks of "SDS plus" rotary bits.

After that, mounting engine on stand was quick and easy work.

Now, I pulled all this out in the first place thinking my clutch was bad. Recently taught lil sis to drive stick and definitely smelled a good amount of burning clutch material. When I checked the clutch out, it wasn't awesome by any means, but definitely not the issue.

I figured out the real problem. Which will have to be another topic. Timing chain bad, way off. I mean still on all the sprockets but way way off. 120k on this chain, you kidding me?

[centralcoaster33]

I'm glad you got that thing off and even more so that your threads are all okay. Interesting thing about the chain. I didn't know chains got "off" without serious issues. Stuff that would seem much worse than a bad clutch. Anyway, maybe another thread for that and some pictures of the chain and timing marks.

[benissimo]

I didn't make a new thread- recently someone had a similar issue with a 2007. I postd my pics there. The sentra forum is starting to look kinda dead, you think I should try posting a thread in a general or engine forum here?

[WDRacing]

I'd have welded a socket or another bolt to the top of the seized bolts. I hate torx hardware and change it out every time it's possible.

I suggest making a new thread with the timing issue. How did the chain jump timing? I've had timing off before and the idle and driveability was awful and that was just one tooth. However, I didn't set the timing correctly, it didn't jump off on it's own. Make a new thread and post some images.

WD

[benissimo]

No room to weld a socket on, at least not with my wire feed welder, because of how the bolts are set recessed in the flywheel holes. Can't fit the gun down there. I agree though that torx stuff is begging to be stripped.

I jumped onto a thread here called 2007 sentra timing chain nightmare, didn't want to post a second topic of the same thing (cause man, on the Linux forums I use, that's a big no-no). However I will start a new one now. Thanks for input

[PapaSmurf2k3]

Wow, that's a lot of work you've done to that Sentra.
I would be super pissed about those stripped bolts. I'd probably write Nissan an angry letter.