Broken Alternator Ear on Water Pump :(
 

Spring cleaning for Red. Oil change. Friction discs. Pads. Grease the suspension. Re-oil the air filter. Blah, blah . . . .

Then I discovered that the water pump ear that secures the alternator is cracked. Like this post (https://www.miataturbo.net/general-m...3/), but mine is still relatively in position. I get belt squeel for a few seconds after startup (during the initial battery recharge), but that's it.

Anyway, TB/WP kit is on order. But I'd love to understand the root cause here as the current TB/WP is only about 1.5 years old. The poster above had his break at least twice in rapid succession. I'd like to avoid that.

I've got Mazdacomp engine mounts, original diff mounts and original damper. Rev limiter at 7500 . . . although I go there often.

Anybody ever experience this? Any advice?

Sharp edges in casting, stress riser, belt a little too tight, all in combination with the rev limit. That's all I got.

Edit- bottom bolt was tight right?

Yes, bottom bolt was nice and tight.

I have subsequently found some other issues. Next weekend's track event is in doubt now.

Same issue here.

My guess is a stress riser in the pump casting. That's my first guess. Second would be engine vibration from a bad/old damper.

I found my lower mount to be pretty oval shaped. This is why the alternator was able to angle in when I cranked the belt super tight to quiet it down. I didn't even notice the lower mount issue until after the second pump broke.

The fix that has succeeded was a new crank key, bolt, a new damper, and drilling the lower alternator mount out and converting to a bigger bolt and nut.
I am still using the Mazdacomp engine mounts and delrin diff mounts. I don't believe they were to blame.

1.6 shines yet again...

So, here we go again . . . .:

https://www.miataturbo.net/attachmen...1&d=1456103838

Upon inspecting the WP, there sure isn't much material there to support the alternator. This is a cheap, Chinese WP that comes in those engine rebuild DNJ kits. Lesson learned.

https://www.miataturbo.net/attachmen...1&d=1456103838

https://www.miataturbo.net/attachmen...1&d=1456103838

Everything else looks good. The lower alternator bolt is snug in its hole -- no significant play. Damper is in good shape. Crank keyway is perfect. Guess I'll just get the replacement parts and put it all back together.

This pales in comparison to the other problem I found . . . https://www.miataturbo.net/build-thr...5/#post1309794.

I'm pretty sure I've got a NIB Gates 1.6 WP (ordering error) for pennies on the dollar. You're welcome to it if interested.