See picture.
http://imageshack.us/f/100/20120313115416379.jpg/

I think this round piece fell off my car today. I heard some squeaking from the right-front and when I got to a stop sign I heard a metal on pavement noise. I'm not 100% sure if it fell off or maybe I ran over it.

I got the car last fall. I have not worked on the timing belt.
Recent work:
torsen diff upgrade, rear axles, drive shaft
front-right wheel hub
oil change
alternator (a few months ago)
power steering and ac are still in place but no belts

 

check your crank. lol.

 

Holy crap. You're right. Here are two more pictures. Do I just need bolts or the pulley too?
http://img600.imageshack.us/img600/3...3133921168.jpg
http://img809.imageshack.us/img809/3...3134043343.jpg

 

Anyone know what size bolts? I believe they are 10, but how long? Anything special?

 

fairly short, same ones in the water pump pulley

that's literally what's holding on the crank pulley.

 

So just add the bolts and it should be ok???

 

hope so. lol.

 

Secure it with blue loctite

Also after you start up your car, rev it to 12000 a few times then look to see if your pulley is wobbling while idling. If so you may have pulley or crank nose sad.

 

At least you caught it.

 

Thanks.

It turns out all 4 bolts are broken in the crankshaft. I'm hoping they can be extracted. I won't really be able to work on it until Friday.

Take a look at this picture: http://img600.imageshack.us/img600/3...3133921168.jpg
The holes on the top and right of the pulley seem to be double drilled. Is it supposed to be like that? If not, why would someone do that?

Do I need a new pulley or can I use the same one?

Good idea. And the loctite turns the engine into an F1 engine, right?

 

You need a new pulley. They aren't double drilled. I'm guessing the bolts weren't torqued properly and loosened over time. That made the pulley enlarge the bolt holes until the bolts finally failed, and you had pieces fall off.

Side note when I bought my miata, I changed the oil, and some bracket fell out. Didn't figure it out until months later when I pulled the motor. It was the alternator bracket. Somebody had changed the alternator, and 'lost' the bracket. The one that was on the alternator was obviously newer....


Bird

EDIT: You're probably going to need a new Pulley Boss too...there is an alignment nipple on it that looks snapped off.

 

+1 on the new pulley. But those bolts aren't in the crank, they're in the lower timing sprocket. I'd highly suggest a new one of those too. FM had a brand new factory pulley on their DOTD a while ago, not sure if it's still available, and I'm not sure where you can get the lower sprocket. Once you get it all, just swap it all during a timing belt job.

 

To OP; So when you came to a stop and that piece fell out, did you drive off? How was it running last?

 

Not sure about the 1.6, but I've got a 1.8 taken apart here, and the bolts actually go into the pulley boss, and not all the way into the timing sprocket...but thats a 1.8 and I haven't seen the 1.6 taken apart.


Pics:

 

Yeah that. Pulley backing thingy. Whatever.

 

Thanks again.
The piece fell off at a stop sign. I drove maybe 15 feet or so and got out and found it. Then I looked under the hood and did not see anything obvious. The pulley was still in place. I drove a couple hundred feet home and now it sits.

 

is the belt still on the pulley?
good luck getting that crank bolt loose now - I would be soaking it night and day with PB
check your crankshaft keyway very thoroughly

 

please don't rev it to 12000.

 

Yeah don't reuse that pulley. You needs a new one.

I would not use generic hardware store bolts of unknown alloy & hardness. Use OEM for that application.

 

FM sells some badass little bolts for your pulley.