Miata broken crank key

Is a broken crank key a death sentence?  I know it's non-interference, but is the repair a massive pain?

what's the worst case scenario?

DrBoost said:

Is a broken crank key a death sentence?  I know it's non-interference, but is the repair a massive pain?

what's the worst case scenario?

Best case is the "loctite fix" (google it).  Worst case is you swap the motor, which really isn't that hard.  Think of it as an opportunity to upgrade to a 1.8 :)

Key itself isnt the problem, how is the keyway on the crank? 

You can get a new key and a new gear that fits on it, but if the crank is borked beyond the loctite fix, it's new crank time. 

Crank snout failures on early 1.6 cars was a thing. I'd have thought they'd all have been replaced by now.

ddavidv said:

Crank snout failures on early 1.6 cars was a thing. I'd have thought they'd all have been replaced by now.

Every 1.6 that I have seen, including the TWO that I serviced last summer, had the original short nose crank.

It's a little weird that every NA that I have ever worked on was a 1990.

Yeah, that worst case is what I feared. That's what's keeping me away. 
my daughter and I are looking for a challenge car. There's an NB with a broken key, according to the owners mechanic. 
if it needs an engine, not sure if it'll work for us for a challenge car. 

ddavidv said:

Crank snout failures on early 1.6 cars was a thing. I'd have thought they'd all have been replaced by now.

The failure wasn't THAT common. There are a lot of them out there. I've got two in my garage right now :)

DrBoost said:

Yeah, that worst case is what I feared. That's what's keeping me away. 
my daughter and I are looking for a challenge car. There's an NB with a broken key, according to the owners mechanic. 
if it needs an engine, not sure if it'll work for us for a challenge car. 

In this case, it's broken because someone assembled it wrong or they didn't torque the front crank bolt properly. There's a very good chance the Loctite repair will fix it if there's any wear. 

It's not just smearing a bit of 242 over the bolt. Here's the writeup: https://www.miata.net/garage/hsue/crank/loctite_1.htm

My 97 got poor service. New, used crank was 200 bones.

Years ago before I had ever heard of Loctite I repaired the power takeoff belt pulley on a Cub Cadet garden tractor after the twist locking collar came loose on the crankshaft. The shaft was worn as well as the keyway.

I used regular JB Weld first on the shaft to build it up and then sanded it down as round as I could and then smeared another batch of JB Weld on the shaft and everything else and installed the keyway and then the pulley and locking collar.

It lasted for years until I had to remove the takeoff in order to replace it for some reason I can't remember. I used a small propane torch to melt the JB Weld and it came right off and was easy to clean up. I then repeated the above steps to reinstall the takeoff.

Sounds about the same as with Loctite.

ddavidv said:

Crank snout failures on early 1.6 cars was a thing. I'd have thought they'd all have been replaced by now.

Does this failure effect '99 cars, or just the 1.6?

In reply to DrBoost :

It affects 1.8 cars that have a loose crank bolt. I think I saw that several times before I saw my first 1990 failure. The 1990 and early 1991 cars would very rarely have a spontaneous failure, but I am of the opinion that mechanics were to blame far more often.

In reply to DrBoost :

The 1.6 had a short crank snout until close to the end of its use in the Miata in the US (mid 1992 or mid 1991) but all 1.8s have the long snout.

By all I mean ALL... like all 1.6 323s had the short snout, including the 323GTX.  I did lots of timing belts on 323s and never had an issue with less than accurate torque.  I know Better now, of course, but somehow things worked out back then.

DrBoost said:

ddavidv said:

Crank snout failures on early 1.6 cars was a thing. I'd have thought they'd all have been replaced by now.

Does this failure effect '99 cars, or just the 1.6?

You may be thinking of the TSB for a mis-sized thrust bearing that affected 99s.  Those have pretty much all failed already, though.

In reply to codrus (Forum Supporter) :

Yeah, those didn't make it past 30k if they had the problem.