$200 Miata: Part 3

"Decay buys too many beaters" (decay)
08/22/2016 at 15:03 • Filed to: $200 miata, Cheap Miata, Decay's Beaters

I finally got around to removing the engine from the !!!error: Indecipherable SUB-paragraph formatting!!! this weekend, and despite the heat, everything went really smoothly. No stuck connectors, fluids all looked decent, and I ended the day with no seized or broken fasteners! I did however notice something this morning as I was leaving for work. I’ll try to convey my discovery process in pictures.

That’s a short nose crank 1.6... which is prone to breaking the crankshaft keyway and was replaced with a much better design in mid 1991 (the “big nose crank” version)... and it just came out of my ‘93.

Despite spending hours working on it, and probably looking half mindedly at the pulley a couple dozen times, it never actually clicked until this morning as I was heading out. I thought “That’s weird, shouldn’t that pulley have 8 slots?” Turns out, yes, that pulley should absolutely have 8 slots if it were actually a 93 engine. For those who don’t know there is a great technical article that goes over the issue here

http://www.miata.net/garage/cranksh…

But long story short, this

Is good

This...

Is not

So now the decision I’m left with is to either fix the oil pan leak, reinstall the engine, and bury my head in the sand on this issue... or dig deeper hoping that I have an updated “long nose crank” or that the damage isn’t too bad to attempt the “loctite fix”. In either case, I’ll probably be running it without A/C or power steering connected to lower the bending forces on the crank pulley as much as possible.

Any Miata experts on here that have dealt with the issue?

DISCUSSION (19)

Takuro Spirit > Decay buys too many beaters
08/22/2016 at 15:07

I recall doing a few of these under warranty back in the day, and we had one customer that SUPERCHARGED their short nose’d engine and blew it up and was like “WHAAAAAA???”

No warranty for you!

Decay buys too many beaters > Takuro Spirit
08/22/2016 at 15:10

Oh fun! I bet all that parasitic loss going straight into the crank pulley didn’t speed up the failure at all!

Jake - Has Bad Luck So You Don't Have To > Decay buys too many beaters
08/22/2016 at 15:10

Hah, that was the first thing I noticed in the top picture. My suggestion? Weld it.

Decay buys too many beaters > Jake - Has Bad Luck So You Don't Have To
08/22/2016 at 15:12

Funny thing is, I know about the issue. It’s like there was a freaking perception filter on that part of the engine due to it being a ‘93. Had it been a ‘90 or ‘91 I’d probably have noticed first thing!

Takuro Spirit > Decay buys too many beaters
08/22/2016 at 15:22

Nahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Tekamul > Decay buys too many beaters
08/22/2016 at 15:31

I’m no miata expert, but if you’re really keeping this project cheap, I’d get a fresh bolt and some loctite.

Also, based on the linked article, if there is a long nose installed, it still doesn’t fix the issue, right? It’s more about the load on the bolt, not the engagement of the the key. The long nose is just to make sure mechanics don’t mess it up.

gawdzillla > Decay buys too many beaters
08/22/2016 at 15:32

since the engine is out already, just replace it with one of those Ferd 302 / LS 1-9 / 1-3UZ / Honduh IJKL 24-32

Decay buys too many beaters > Tekamul
08/22/2016 at 15:40

My understanding is that the long nose increases the engagement area of the key and should reduce wear.

But yeah, that’s the plan right now, might as well disassemble and see just how bad the wear is.

Decay buys too many beaters > gawdzillla
08/22/2016 at 15:44

Were I doing that I’d want to start with a way cleaner example. One without rust... and ants... and bondo... and ruined paint...

But If I did, it would be one hell of a sleeper with how rough it is, hmmm.

Tekamul > Decay buys too many beaters
08/22/2016 at 15:53

Knowing the dimensions, could you maybe source a bolt with a higher hardness rating? Then, like Jake said, weld the sucker. After changing the crankshaft seal 1 last time, of course.

Decay buys too many beaters > Tekamul
08/22/2016 at 15:59

Perhaps if it comes to that I might see what mcmaster has to offer.

Roadster Man > Decay buys too many beaters
08/24/2016 at 08:44

I’m no expert, but I’ve spent a long time on the Miata forums. So long as there isn’t bad damage, most Miata guys swear by the loctite fix.

Decay buys too many beaters > Roadster Man
08/24/2016 at 10:37

Yeah, going to take everything apart this weekend and peek. Hopefully everything is still servicable.

Roadster Man > Decay buys too many beaters
08/24/2016 at 18:19

Hopefully it is. A LNC to SNC engine swap is one of the strangest things. Definitely a contributor to the price- because who in the world would go through the trouble to swap in a less reliable engine?

If it’s a ‘93 then a swap is the only explanation I can think of. Someone along the line probably picked up an engine at a junkyard without being aware of the issue.

Decay buys too many beaters > Roadster Man
08/24/2016 at 19:12

I think the LNC was another deal altogether, it still might have that and I won’t know until I pull it apart. It shipped with a BNC.

I’m not sure what was going on with whoever did the swap, but I do not believe it was the guy I bought it off of. He was either really adept at playing the layman or didn’t know a whole hell of a lot about what was going on under the hood. I’ve got a few feelers out to local miata facebook groups to see if anyone has a backstory on the car.

Roadster Man > Decay buys too many beaters
08/24/2016 at 19:18

I have a little faith in humanity, I would like to think that the seller just didn’t know. I carfaxed my Miata when I bought it and it had like 6 previous owners. Thank goodness nobody messed around with it. Until I got it...

Decay buys too many beaters > Roadster Man
08/24/2016 at 20:35

I would love to see the history of mine. Given the amount of bolts I found missing, none of the work was done at a shop!

KatzManDu > Decay buys too many beaters
09/07/2016 at 18:48

Junkyard rotary swap.

Decay buys too many beaters > KatzManDu
09/07/2016 at 18:51

I almost bought a wrecked Saturn Vue for swap purposes last week!