ssherman68

I just did an oil change after 3,500 miles and 5 months. This is my third change on this car and the last two were completely clean. It's a stock 1999 C2 and I've had it a little over a year.

This time I noticed some small ferrous metal flakes on the filter. The difference this time is I did three 2 day HPDE driving events on the oil. I'm a beginner so I'm sure I wasn't pushing it as hard as someone with more experience would. So I'm wondering if this is a new situation developing or if I may have knocked some debris loose on the track. That or there were some oil starvation events during turns and this is the result. PO replaced the IMSB with an LN dual row about 10K miles ago.

I doubt it's the IMSB. Camshafts? I'll check the deviation with a Durametric in the next few days. Every other time I've checked it's been 0%. I also sent the oil out to Speediagnostix. This will be my second sample to them.




Magnetic drain plug - Burnt oil?

The smudge on the top right is what came off the plug

One of the most populated sections of metal flakes. Look in the creases

Wider view of filter. Again, look in the creases

This is the bulk of the metal I was able to pull off with a magnet

Flat6 Innovations

What oil were you using on the track? How many miles did the oil have when you went to the track the first time?
I suppose both track days were on this same oil?

ssherman68

It was Motul XCESS 8100 5W40. It only had ~700 miles on it on the first track day. I did 3 track events on the oil. The first one was my first track event ever and I was in the beginner (green) group on all 3 events.

Flat6 Innovations

Not good. This looks like a delimitation of the [crankshaft] main bearings to me, or wear of the crankshaft end thrust shims.

ssherman68

Oh man. Is there a way to verify or narrow this down without taking the engine apart? Is there a downside to running it a few hundred or a thousand miles and checking again?

Flat6 Innovations

The next thing that needs to be done is sump plate removal, and inspection, before you even put oil back into it..

jobyt

I'm no expert, but looking at the color of those flakes, I'd venture the answer is *no*

Again, noting my lack of expertise on this subject, I'd also speculate that at this point, running this engine any further will result in catastrophic damage that *can* be potentially avoided with a full tear down now.

My opinion (and take it for the lack of value it has): stop running this engine and get someone with experience to help you with a teardown to replace some bearings that are now fast wearing. You may be able to save the crank, carrier and associated core parts before it is too late.

Best of luck to you and sorry if this is a downer.

ssherman68

I figured I would drop the oil pan but wasn't sure how long (if at all) to run it for first. I had already put oil in it and ran it around the block once before discovering the flakes. The uncut filter looked clean.

JTT

I’ve been where you are. Deep breaths. Since you’ve already refilled with oil and run, maybe try pulling the filter again (you can pull the filter without draining all the oil) and have another look. This was my filter a few years back. Material was ferrous. After a fairly extensive exploratory search, it turned out to be my IMSB (which had been swapped for an LN bearing by previous owner). Before the boo-birds jump in and start dumping on LN, there is no way I can confirm how the bearing was installed, handled or treated, so I can’t blame the bearing or LN. For all I know the bearing had been dropped on the floor before installing. Charles from LN was extremely helpful in helping to diagnose mine. Standup guy in my books.



I am curious about the main bearing and/or thrust shims...ferrous? I would have assumed these were other non-ferrous materials, but have never seen these in person.

theprf

The bearings have a ferrous (steel) backing plate that's plated with a copper flash and then layered with a "white metal" surface that is actually presented to the crankshaft. "White metal" used to be a lead-tin concoction, newer formulas may have changed to any number of similar metals. The important thing is that the "white metal" is softer than the steel of the crankshaft.

The trouble happens when the white metal wears off or melts off the backing plate. Then you have steel to steel contact from the backing plate to the crankshaft. This can quickly score the crank, which is not regrindable in the M96. The white metal can wear quickly if oil is interrupted with the engine under load, and with it's melting temperature somewhere around 500F it can melt and run out of the bearing space if overheated.

The secondary trouble happens because the loss of the white metal increases the bearing clearances. If this happens on a main bearing, the rod bearing that is fed from that main bearing is starved for oil and will quickly fail. DeJeeper's engine failed this way.

De Jeeper

It should also be said that u r not the only one to see this and there may still be years of street driving on yout motor. Mine had 200k in the clock and i firmly believe i could have got many more had i not been driving at 7k one the track.

I would think u are fine to drive around and monitor the oil pressue but u may want to lay off the track until u get more info. Some of us r currently trying to test oil pressure drop in another thread. There still is no commercially available solution to the internal decay of our motors due to pressure drop but there r things u can due to help limit the damage. Race oil with frequent changes and keeping oil temps down r both important.

JTT

Thanks for the explanation! That makes perfect sense. Much appreciated.

TexSquirrel

If it were me, I would open a ticket at Flat6Innovations and ask all your questions there.
Even if you don't ultimately have them rebuild your engine, you can pay for consulting, which is probably worth more than it's weight in gold!
The paid consulting is something that they offer that more people should take advantage of, IMHO!
Asking here for free is a good first step, but the next best step is to pay for their expertise.

Mpfaff

Material is coming from somewhere.....been there,a member on this board has my old crank (paperweight).
I feel your pain.

Flat6 Innovations

Again..
Pull the sump plate, document what you find in the floor of the sump. This is THE FIRST step to diagnosing any internal issue with these engines. The sump plate is a window to the soul of the engine.
You need a 10mm socket, ratchet and a large screwdriver or pry bar to remove it. This will take you less than 30 minutes, even if you are slow. My 9 year old daughter pulled one last week in 11 minutes by herself, but she's done it before.