Zmanco Posted November 4, 2007 Share Posted November 4, 2007 My front main seal began to leak and after pulling the harmonic damper off, here's what I found. Obviously the damper and the woodruff key are scrap, but I'm worried about the crank, specifically the hole for the woodruff key. It looks enlarged which isn't surprising given the condition of the key itself. The oil scraper (I think that's what it's called) behind the seal should slide over the crank and come out, but it's hanging up on the enlarged edges of the key hole on the crank. I really don't want to tear the engine apart given I just rebuilt it about 13k miles ago. Suggestions? Quote Link to comment Share on other sites More sharing options...
dexter72 Posted November 5, 2007 Share Posted November 5, 2007 I would try using a mini file to file down the high edge where the keyway mushroomed the crank. First shot for me would be a new key and some jb-weld or some type of good quality metalbond. You still have a good side where that keyway slides in. The metal bond or jb-weld should be able to fill in the rounded out side of the crank. Install the keway and then add the metal bond to it. Wait a couple of days, and work on filing down the area smooth that was bonded. Install a new balancer and apply locktite to the crank bolt. I thought that the keyway does that when the crank bolt is loose, causing the balancer to move side to side. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted November 5, 2007 Share Posted November 5, 2007 I'd use lab metal for the repair. It can be found at most welding supply shops. It is only the the hub will prevent that repair from being displaced that the repair should hold. I've personally done this on a 327 SBC that ran over 10,000 hard miles prior to being sold. It never showed signs of failure. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 5, 2007 Author Share Posted November 5, 2007 Thanks guys, I'm encouraged that you think I can fill in the keyway and not have to tear the engine down. dexter72, is a "mini file" a specific type of file, or just one that is small? I haven't heard that term before. Quote Link to comment Share on other sites More sharing options...
terrycoxusa Posted November 5, 2007 Share Posted November 5, 2007 jb weld is s**t. I would buy a slightly larger key and carefully grind the crankshaft groove to fit. You can grind or file the top half of the key to fit the pulley. I've done this before, it's not hard. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 5, 2007 Author Share Posted November 5, 2007 jb weld is s**t. I would buy a slightly larger key and carefully grind the crankshaft groove to fit. You can grind or file the top half of the key to fit the pulley. I've done this before, it's not hard.With the crank still in the car, I'm having a hard time seeing how I'll be able to grind the crank keyway. What's the best way to do this? Find some small files and just go really slowly? Also, here the info on Lab Metal: http://www.alvinproducts.com/Products/Products.asp?ID=1 Looks like it has aluminum in it. I'm still concerned that any of these fillers will hold up at sustained high revs. Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted November 5, 2007 Share Posted November 5, 2007 To dress the crank snout you'll be better off pulling the timing cover. Don't be concerned over the materials in Lab Metal. The stuff is about a tough as any epoxy type product comes. It is far superior to JB. That being said, there is no guarantee that this fix will hold up. It is quicker and easier than pulling down the engine and replacing the crank. I'm betting the bolt came loose allowing the hub to walk off the snout causing the damage we're seeing. My point is that once the keyway is dressed, lab metal'd, and hub installed there's no where for the epoxy to push out to. Excessive crank vibration can realistically cause the epoxy to be pounded into powder and bringing you right back to this point. Keep an eye on it including bolt torque. I'd spot paint the bolt head/washer/hub to have a visual if things start coming apart. Terry's option using a new key is a possibility too. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted November 5, 2007 Share Posted November 5, 2007 The crank snout key way was also a problem to some early Miatas. I believe the say a specific kit to fix the key way in the crank for them, and that it's been used by people before. Also, some people remove the crank, take it to a machine shop, and have it rewelded and cut. Mario Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 13, 2007 Author Share Posted November 13, 2007 I haven't had time to work on the Z lately, but have been thinking about options. If I was to take the conservative route and replace the crank, I'm wondering if I can reuse my rings? I know I'll have to push the pistons out, but can I reuse them when I reassemble? The block was bored 30 over 15k miles ago with new pistons and rings. If I can, then I'll just need a new gasket set and bearings for the crank and rods. It will be a lot of time spent to do this all again, but I suppose I can find time over the holidays. What do you all think? Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 13, 2007 Share Posted November 13, 2007 This problem has been addressed before. Someone posted a detailed link on how to fix it with a loctite product specifically made for that use. Do a search and find the fix. The article was directed toward a Miata, so try using that word in the search Quote Link to comment Share on other sites More sharing options...
Zmanco Posted November 13, 2007 Author Share Posted November 13, 2007 Pop N Wood, I know there are many who have done this fix using either Loctite 660 or Lab Metal to build up the space between the key and the keyway. There's also Loctite green to help hold the damper on the crank snout, and Loctite red for the crank bolt. I've already sourced a new damper as well as ordered the longer crank bolt from Courtesy Nissan (thanks Yasin!). I know it will be a much quicker fix to go the Loctite/lab metal route, but only if it holds. I've "cheaped out" in the past, and nearly always regretted it later. Hence I'm trying to better understand how big of project replacing the crank is going to be. My question at this time is if I decide to go the conservative route and replace the crank, do I have to replace the rings (and hone the block), or can I just put the pistons back in again? BTW, here are the relevant links: http://forums.hybridz.org/showthread.php?t=115687 http://www.mx5.net/garage/hsue/LoctiteCrank1.html http://68.72.74.113/PRODUCTS/660.htm Quote Link to comment Share on other sites More sharing options...
Xnke Posted November 14, 2007 Share Posted November 14, 2007 NOTE: this event happened before I became a Z lover. After this experience, I couldn't wait to get my own! Why would you even need to remove the pistons? I've dropped the crank out of several similarly built cars without pulling the motor...transmission was already gone, so you just gotta pull the oil pan and front cover, and be very careful not to tear anything up. That front crossmember will get in your way, though, on second thought. Best to just pull it, and be careful how you pull the crank. By the way, when that crank falls out and hits you in the face, it WILL break a cheekbone...even if it's only in a little four banger... After I did this in a few transversely mounted I-4's, I grew to love the large, roomy engine bay in the Z. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted November 15, 2007 Share Posted November 15, 2007 The only reason you would have to re-hone the block would be if you installed new rings. You don't have to hone the block out again. You should be able to tap the pistons up enough in each cylinder to remove the crank without pulling each piston out. Use rubber hose on the rod studs so the studs don't scratch the crank, when tapping the pistons back down onto the replacement crank. There is also a plastic sleeve protector to cover the rod studs, don't remember who sells them at this time. Sure some performance shop sells them in your town. I have done the repair suggested earlier in an 87 toyota cressida, when I worked at a toyota dealership. It held up and worked with no issues, had the car for 3 more years before i sold it. It was my daily driver by the way. Quote Link to comment Share on other sites More sharing options...
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