From a frustrated 944 owner to you engine builders. Alu dust in crank case.
 

I bought an expensive "no-fault" 944 turbo this time last year which quickly lost boost. Turned out that a washer had entered the intake and was eating my compressor wheel. This, combined with the need to change all things rubber lead me to pull the engine.

I finally installed the engine a couple of weeks ago and have been on a few very short drives since then. When checking the oil I discovered a gray residue/coloring on the wipes. I first thought it be traces of the assembly lube, but today I discovered aluminum dust in the intake plumbing and crank case vent pipe. Turns out that my turbo has decided to eat itself again. This time the compressor wheel is grinding itself to bits on the housing.

I have owned this car for a year, and have driven less than 200km. Apart from this problem the car is faultless, but this setback has me considering selling it as a project. I understand that I need to drop the engine again to fix the turbo, but please tell me there is a quick way to flush out the dust other than taking the engine completely apart to clean the galleys and crank case.

I don't understand how you would end up with AL dust in your crankcase if your turbo is lunching itself, unless you have severe blow by on your rings the dust should have just gone right thru the engine and out the exhaust. Did you replace all the bearings and rings? If so you are going to have some metal particles from the break-in, hence why you change the oil after a short period. I would fix the turbo, or remove it for now, change the oil and run the engine for a bit, then change the oil again.

Thanks for replying.
I did not touch the rings or split the head from the block. I installed crank scrapers and new bearings. I have no bad blow by, oil is still clear and smells like new. I was thinking the particles must have entered through the crank case venting, but I just realized that the connection is before the turbo and so should be under constant vacuum. Maybe it is just assembly lube after all and I am confusing the issues. When that is said I did find some small sand sized aluminium particles in the oil. They look exactly like the ones on my intake plumbing. I am filtering an oil sample now. I'll have some more answers tomorrow

Two issues:

1) If the turbo is destroying itself, replace the turbo.

2) After #1 is done, re-evaluate the oil condition.

You need to figure out how the metal got into the oil and what has been exposed to the metal particles. Maybe cut the oil filter open for clues and for sure remove the oil pan and check things out from the bottom.

Maybe the washer caused a bearing issue in the turbo?

@AlfonsoR. Turbo was rebuilt and rebalanced. I still don't know why it failed.

I have now examined the situation further and it seems like the huge disappointment made me instantly assume the worst. Pulverized compressor dust looks very similar to gray assembly lube, which I now believe the residue in the oil is. I took a sample of oil from the pan after letting the oil settle for a few hours and filtered it through a coffee filter. I only found a couple of tiny unidentified non magnetic grains in there. No hints of glimmer or AL dust. I will have to change the oil when pulling the engine anyhow, so I hope I will be safe in that department.

I still need to get over the disappointment and practical issues of having to pull the engine and being without a car for another several months, but that is a different issue. Thanks for your replies and please let me know if you disagree with my diagnosis/analysis.

You should have your oil professionally analyzed and that will tell you exactly what "foreign" material is suspended in your oil sample

Thanks. Will do that. I managed to remove the turbo without dropping the engine.
I'm thinking this will work out better than I feared.

I had the same thoughts after my break in on my SC. The assembly lube build up is very disconcerting and I posted the same thing you did here! Run it, change the oil and re-evaluate.

Best regards,

Michael

Uh, did you clean all the intake plumbing, turbo piping AND the intercooler in the nose. You are seeing residual remnants of the first turbo compressor wheel. Maybe you did clean these pieces, but have neglected to let us know. The intercooler is a design that lets foreign matter collect at the bottom of it. Have it professionally cleaned.

Ask me how I know this. The very same thing happened to me on my 951. I replaced the turbo, cleaned everything and ran cheap oil through it twice. These are very strong motors.... It ran great after that.

Good luck.