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-   -   Metal flakes in the oil filter.. (https://www.miataturbo.net/engine-performance-56/metal-flakes-oil-filter-65360/)

guzerone 04-22-2012 11:41 PM

Metal flakes in the oil filter..
 
6 Attachment(s)
What's this stuff?

Looks like thin flakes. It sticks to a magnet but not like steel, comes off the magnet a lot easier than steel shavings.
So not aluminum, not steel. Could it be bearing material (some alloy containing some steel)?

I rebuilt the engine 1000 miles ago, just rings, bearings and forged rods.
A small radiator leak lead to a blown head gasket. I took this as excuse to install forged rods (SGI forged H-beam) :drool: to get ready from moar boost.

The block needed to be decked because the surface was pretty pitted.
All the wear tolerances (bearings, end play, ring gap, oil pump clearance, etc) were about halfway between min and max after 160K miles, 11K of which with 8-14 psi from a 2554r. The oil pump relief piston and spring were worn so I replaced those.

Faeflora 04-22-2012 11:44 PM

Bearigs.

fooger03 04-23-2012 07:32 AM

When you replace the bearings, you're going to want to do a pretty comprehensive examination of your oil pump and the associated pressure relief valve. Failing bearings can own your oil pump.

BogusSVO 04-23-2012 11:53 AM

I will have to agree with the 2 above me.... Bearings.

Did you have any crank work done? Polish? Grind?

guzerone 04-23-2012 02:24 PM

Yes, I had the crank polished.
I checked the oil pump for clearances, all within spec. The pressure relief piston had some scoring (the bore looked fine) so I repleaced it.
The Spring was worn (free length was under spec'ed minimum) so I replaced it too.

I guess it's time to pull the engine (again) and see what's going on.

Has anyne around here used Toga Race bearings?
They have a groove in both bearing caps, not just the upper.

Gunter

BogusSVO 04-23-2012 02:32 PM

Ahhhh did you clean the crank before you installed it?

guzerone 04-23-2012 02:37 PM

The shop cleaned it and I cleaned it again (blew out the oiling passages, etc).

fooger03 04-23-2012 02:40 PM

The oil pump could very well have been a rockstar when the damage occurred, but all those little metal shavings in your oil filter had to travel through your oil pump to get there, this is why I suggest inspecting the pump - you wouldn't want a future stuck pressure relief valve causing you to have to do *yet another* teardown/rebuild. /rainbowbarf.jpg

hustler 04-23-2012 02:57 PM

gut it. Those aren't shavings, their shards. something is on the way out.

Savington 04-23-2012 03:45 PM

Do not run the motor any further. If you pull it now, the repairs will cost you about 30% of what they will cost you if a bearing fails.

IMO, I would not reuse the oil pump from that motor under any circumstances.

BogusSVO 04-23-2012 03:52 PM

Did you get to clean the intersecting oil galley from the main to the rod throw?

If not, Trash , grit and get caught around the oil galley plug in the rod throw.

guzerone 04-23-2012 04:44 PM

Oh well, ordering a gaset set and an oil pump now...
Good thing I didn't sell the engine hoist and stand like I initially planned.

guzerone 04-25-2012 12:01 AM

Found the culprit..
 
2 Attachment(s)
The #2 rod bearing is toast..

I posted hi-res pics of all the bearings at:
https://skydrive.live.com/redir.aspx...ive&Bsrc=Share


The strange thing is that the neighboring main bearings are OK and the oil passage in the crank is not obstructed. No idea what destroyed the bearing.

Any theories?

The rods are SGI forged H-beam (there ar some threads on these).
The bearings are ACL, std size.

The cleanup is going to be tedious, metal flakes everywhere...

Savington 04-26-2012 09:59 PM

What was your initial start-up procedure and break-in procedure?

falcon 04-26-2012 10:18 PM

I've never seen a bearing look like that before after tear down.

BogusSVO 04-27-2012 11:04 AM

Make sure to have the big end of the con rods checked for size and round.

guzerone 04-27-2012 12:04 PM

I installed the bearings in the rods and torqued them then went to the shop that did the machining and had him mike the rods and crank for clearance, it checked out OK (0.0019 - 21).
After I put the bottom end back together (with plenty of assembly lube) , I installed the head. Before I put the cam shafts back in, I primed the oil pump by pouring down oil to the oil pump through the oil filter opening. Then I used a beefy drill to spin the crank until oil came out of the bores that lubricate the cam shafts to make sure that there are no obstructions. After installing the cams, and the rest of the top end, I hooked up the oil pressure sender and spun the crank again using the drill for another couple of minutes, oil pressure was around 40 PSI, not sure what the revs were somewhere around 600 - 700 RPMs. After putting the engine back in the car, I fired it up and let it idle until it reached normal operating temp (oil temp around 180F).
After that, I shut it off, let it cool down and change the oil filter. I cut open the oil filter I took off, it was clean.

As for break in, I unhooked the waste gate for the first 50 miles or so and did lots of accelerate/overrun cycles to seat the rings. Then I hooked up the waste gate again and took it easy for the next 200 miles or so (that was the hardest part...), still doing accelerate/overrun cycles. The next 750 miles, I drove it normally, avoiding super-high RPMs. After 1000 miles, I drained the mineral break-in oil and thats when I found the flakes in the filter.

Savington 04-27-2012 03:18 PM

Sounds perfect. Bummer.

Snap some pictures of the rest of the bearings.

guzerone 04-27-2012 06:42 PM

Some more hi-res of all the bearings: https://skydrive.live.com/redir.aspx...ive&Bsrc=Share

hustler 04-27-2012 06:50 PM

What causes wear like that, engine crew?


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