Thanks for the info on the crank issue Rocket. After reading up on that, running back and forth and looking at my crank, then reading up on the loctite fix.....well I've had a stressful morning hahaha. I'm pretty sure I've got the short nose crank here, but I need to go out to the garage and get my calipers before I'm positive. I found a detailed guide on the loctite fix that the article you linked mentioned, and it doesn't really seem all that bad. It's just a bit scary that Mazda let such a bad design flaw get through R&D like this. I don't think my keyway looks worn out at all, but until I measure it I don't know for sure how bad this situation may really be.
I'll be editing this post later with some pictures and more information. Thanks for making me aware of this problem. I'd be incredibly upset if I didn't find out about this until it was all back together.
And GreyWolf, thanks man. I figured with the service manual, anyone should be able to follow instructions and take apart/put together their engine. I'm trying to show the things they don't mention in there, that'll give you a better chance of success.
Also, does anyone know if I should pack the oil pump with vaseline, or use assembly lube on the gear set? I've done the vaseline trick with a couple older small block Chevy's, and I like the peace of mind it gives. Would the same principles apply to priming the oiling system on these cars? Or is it better to just disable fuel and spark, and spin these engines over with the starter in order to build oil pressure before first start up?
EDIT:
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Well, damnit. I had a feeling, and this confirms it. I have the problem child. So it looks like I need to track down a new woodruff key, crank pulley, crank bolt, and some loctite 660. Lovely. That loctite 660 is extremely expensive, too. Looks like tiny 5oz tubes are going on Amazon for about $30. Is this something that absolutely needs to be addressed? Or is it something where if I'm extremely careful torquing the crank pulley bolt down, it may never be a problem? Damn it..... I guess either way I'll probably end up doing the fix. For anyone who finds this in the future, here is the guide I found:
https://www.miata.net/garage/hsue/Loctite%20Crank%20Fix%20-%20Part%201.htmSo I put the nose of the crank back together, not torqued or anything, just kind of placed the parts where they should go. I don't see any wear or signs of slop on anything. Do I necessarily HAVE to replace these parts? For example, do I NEED the OEM Mazda crank bolt (Part# 630-11-406C)? Is it the larger one, and does it require the higher torque setting? Or can I just clean up these parts I already have, and simply apply the Loctite 660 to the woodruff key and the gear? That bolt alone is $30 too, so I'll be spending probably $200ish to fix this correctly if I follow that guide I linked (Depending on price of harmonic balancer and gear).
ANOTHER EDIT:
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Alright, I've done some more reading. Looks like my tentative plan is to replace that crank bolt and woodruff key with new OEM parts, then use the Loctite 660 stuff on it when I reassemble. Should only cost me around $60 or so, and it seems like the best way to go about fixing the issue for my goals with this car. Just a bit annoyed that now the crankshaft bolt is going to have to be a maintenance item. If this engine ever comes apart again for more serious modifications, I'll be going into that project knowing I need to replace the crankshaft, front covers, and oil pump.
I know the Loctite 660 is supposed to be used on the keyway and the back of the gear. I'd imagine that stuff is crazy strong, and NOT what I'm supposed to use on the threads in the nose of the crank that the pulley bolt goes into, correct? What should I use there? Red? Blue?