Head crack around lifters
 

Any thoughts on this one?

#4 - exhaust side
https://www.miataturbo.net/attachmen...ine=1344560069


Noticed a rattling coming from the head a few days ago and I pulled the vc and found this and the piece broken off just sitting at the bottom. No foreign objects in there and no other damage.

Next question I guess is, the lifter still moves freely and with no other damage - how bad would it be to just leave it like this?

The fact that you heard rattling means that it will probably continue to do so and fail at some point. I would replace the head before it does fail and maybe does damage to other parts when it goes.

On a side note, I have seen many heads from 99 up that the areas around the lifters were not completely filled with aluminum when they were cast. This may be what will be the end result. Poor quality control.

It was completely filled...the missing piece was broken off and sitting at the bottom. Im figuring that piece bouncing around was the source of the rattle.

JB weld it back in place and forget it.

Yea, I thought of that but I'm thinking just leaving it with ~80% of the lifter hole would be better than risking the JB Weld not holding and the piece actually tearin' ---- up next time around.

Another thought, short of replacing the head, is to have the wall rebuilt by a decent welder and a shop re-bore the hole.

If the piece shows that the hole wall was complete, you should try to see why it broke. Any marks on the cam lobe?

In my layman's opinion: It seems like it was just a weakness in the casting. The rest of the head looks perfect, nothing else in there, no damage to anything. The wall on that one did look noticeably thinner than any of the other ones.

I guess it just had enough :dunno:

I put it all back together and drove it around the block and it seems ok. We'll see if the rest holds out. :o

Seriously? Want to ruin the bottom end too when it pumps a bunch of aluminum through the oil pump and bearings?

Replace the head ASAP. Don't drive the car until you do.

any decent aluminum head shop should be able to fix that up for you...