I got iron and aluminum in my oil, now what???

[Ciotti]

Here's how it all went down...

1999 with 80,000 miles that's been autocrossed hard in the last 4 or 5 years of it's life but runs STRONG. I got it a year ago, ran compression, 210's across the board, I've never noticed it using oil but I have been checking the dipstick when I get gas and I'm now reading that our dipstick tubes get coated in oil as soon as we start driving and to get an accurate reading we need to check the oil after the car's been sitting for a while.
Put Amsoil XL(10,000 mile) 5w30 in with an OEM Mazda filter June 2012, it's been probably 9,000 miles since then with a number of autocrosses and Miatas in Boone thrown in there as well.

Everything's been completely normal, no tapping or knocking or anything out of the ordinary all winter driving it 3 miles (15 minutes with traffic) to and from work every day.

2 Thursdays ago on my way back from karting I wound it out a few times on on/off ramps, nothing too crazy just a little blow the carbon out of the motor session, and when I got home all the normal parking was filled up so I had to park on the other side of the lot which is on a downhill with the nose of the car down.

Friday morning...

Start car
Nasty knocking for 1 - 2 seconds
Goes away for 3 or 4 seconds
Starts to come back
Shut car off

Check the dipstick
Bone dry
Frown
Dump in the 1 extra quart of Amsoil I had
Start car
No knocking
Drive to work

No noises on the way to work, happy days are here again it was just a bit low on oil

Work late
Start the car
Nasty knocking for 1 - 2 seconds
Frown
It goes away again and doesn't come back
Limp the car home and park it in the normal level ground parking spot

Saturday...

Check the oil
Bone dry dipstick
Slap forehead
Don't have any more Amsoil so I don't start the car again

Tuesday...

Finally get my hands on some more Amsoil
Dump in a quart
Check dipstick 2 or 3 times
Oil level is now definitely on the stick in between the L and H

Wednesday...

Check dipstick again
Same oil level
Start car
Same god dam knocking for 1 to 2 seconds but then goes away
Limp to work no weird noises car feels fine
Park it at work and let it sit for 10 minutes
Check oil level
Same spot on the dipstick
Start car
Tiny faint knocking that goes away after 1 second
On the drive home I notice that under probably %1 throttle where the motor's not loaded up and pushing the car faster but it's also not decelerating/engine braking, there's a little tapping that you can hear 45 seconds into the video below...

http://www.youtube.com/watch?v=Bl9Oz8-RmSM&feature=share&list=UUek8LlmHeIiU_s62lpxcD6w

And here's the loud knock when I start it

http://youtu.be/dYMSSQ-d_zw


Changed the oil and filter, no difference whatsoever, but I collected a sample from the oil coming out and sent it to Blackstone for analysis

I don't know how accurate the Comments section is since I'm not sure if they actually look up each motor to see what type of metal each part of the motor is, BUT my take-away is that there seems to be an awful lot of Iron and Aluminum in the oil.

http://www.ciottiindustries.com/gallery/Miatas/Ernest/ZAnalysis.jpg

I'm running compression this weekend to get another data point, but what do you guys think I chewed up here?

I was hoping it was just a spun bearing but I feel like the oil analysis tells a different tale.

Thoughts?

[wannafbody]

Aluminum and iron reads are in a normal range. Iron over 150 is a potential issue.

[Ciotti]

The Aluminum average says 3, I'm at 23 and the iron average says 9, I'm at 51 :(




Compression test results...

160
160
160
150 (put some oil in and it jumped up to 230)

6 months ago all 4 were at 210 but that was with a different gauge that I had rented so who knows how accurate is was

[wannafbody]

Iron and aluminum readings in an oil analysis aren't a indicator of wear in and of themselves because they are so minute. Drain the oil and look for chunks, if you see large chunks you have an issue.

[kung fu jesus]

Ever check your crank for play?

[Ciotti]

Iron and aluminum readings in an oil analysis aren't a indicator of wear in and of themselves because they are so minute. Drain the oil and look for chunks, if you see large chunks you have an issue.

When I changed the oil there weren't any chunks, but the rod knock in the videos is an obvious sign of damage no?



Ever check your crank for play?

I did although not with a gauge, I can't feel any play, when I have someone put the clutch in I can't see any play, and the knocking doesn't change at all whether the clutch is in or out so I've sorta ruled thrust bearing failure out thus far.

[kung fu jesus]

I'm stumped. My wife's '99 has similar oil symptoms, but no ticking. I need to comp test it this spring. I will definitely be watching this thread.

Thanks for posting the detailed information!

[Ciotti]

I'm trying to figure out if I'm going to replace with a stock motor or rebuild this one, I like the rebuild option since I have total control and there are a few STR legal things I can do to make some extra ninja horsepower (020 on the block and head) but it'll be quite a bit more money so I'm just not sure.