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-   -   brass dust suspended in oil (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/401320-brass-dust-suspended-oil.html)

bkreigsr 03-31-2008 07:51 AM

brass dust suspended in oil
 
I'm doing the switch from Valvoline Racing 20-50 to Brad Penn, and noticed a lot of brass dust in the oil. Is this the death knoll?

I'm going to send a sample out to Blackstone Labs, but in the meantime, what else, besides the valve guides, is made of brass? Cam/chain drive gears? Distributor drive? Anything related to the turbo (K27-S) itself like sleeves/bearings?

Also, I don't know if this is related or not, but my motor has always generated a lot of the white milky oil/air combination. I noticed a good deal of it while I was re-routing a couple of the vent hoses over the a/c lines, and an accumulation in the bottom of the oil tank.

Thanks in advance

Bill K

equality72521 03-31-2008 07:57 AM

Maybe rocker bushings?

bkreigsr 03-31-2008 08:05 AM

rocker bushings - forgot about them, good candidate, as the car does not smoke after start-up.
thanks Mark

Bill K

JFairman 03-31-2008 08:47 AM

I've seen that when looking at used motor oil in sunlight, especially on a freshly rebuilt motor. It is disconcerting...

I'm not sure it's all brass dust because it could be steel dust that looks goldish colored while it's suspended in the dark amber colored used motor oil.

Another source for brass/copper dust is the bearings if the lead babbit has worn off the main or rod bearings.
Those shell bearings are 3 layers of metal.
Steel/brass in the middle/lead babbit on the running surface.

bkreigsr 03-31-2008 08:58 AM

I'm hoping that any steel gets picked up on the drain plug magnets. Both were free from any shavings. Plus, I ran a strong magnet through the drained oil and it came out clean.

mb911 03-31-2008 10:29 AM

one thing to consider also is the oil pan pics up dust and with gold tinged oil can make the dust look like brass

copbait73 03-31-2008 10:53 AM

Quote:

Originally Posted by bkreigsr (Post 3860105)
Anything related to the turbo (K27-S) itself like sleeves/bearings?
Bill K

Almost without exception (ball bearings) turbos will have two bronze turbine shaft/wheel journal bearings and a bronze thrust bearing.
If your report shows bronze you can give your turbo a quick review. Remove the compressor inlet tube and inspect the compressor blades for impact marks. Many turbos ingest junk and fail. If all looks good here check for radial (side to side) and axial (fore and aft) shaft movement.
Generally, if the compressor wheel blade tips are not touching the housing on the radial test journal bearings are OK. Normal axial play is a few thousands and barely detectable with a good thrust bearing. If you have noticeable axial play the thrust bearing is worn.

fredmeister 03-31-2008 11:30 AM

I would guess distributor drive gear wear. How does the distributor gear look when you pull it?
You may be able to see the drive gear thru the hole in the case when you pull the distributor.
Did you check the rocker arms for free play when doing a valve adjustment?
If your turbo bearings were bad it would be smoking like a MOFO.......any oil in the intercooler or compressor housing?
Good luck.

930gt-40r 03-31-2008 12:27 PM

Jfairman- your the first person I have heard aside from my grandfather that used the correct terminoligy when talking about bearing material (babbit)

bkreigsr 03-31-2008 12:38 PM

I haven't had the nerve to start monkeying with the dizzy and timing yet, nor have I had the valve covers off. The car has been running flawlessly once I got the exhaust and electrics sorted out in 2006.

also, car is in its original configuration - no i/c.

I don't think it's dust, I think I saw it in the drain stream before it hit the pan.

Bill K

equality72521 03-31-2008 01:14 PM

Quote:

Originally Posted by 930gt-40r (Post 3860668)
Jfairman- your the first person I have heard aside from my grandfather that used the correct terminoligy when talking about bearing material (babbit)

That's because you don't any electric motor winder/mechanics. We all know about scraping babbitts. :cool:

NathanUK 04-01-2008 12:47 PM

The timing chains and tensioner pulley teeth are not made of brass or bronze.

Craig 930 RS 04-01-2008 01:06 PM

I hope to God you don't find what I found:
http://forums.pelicanparts.com/uploa...1207083895.jpg

Brassy lookin':
http://forums.pelicanparts.com/uploa...1207083964.jpg

Craig 930 RS 04-01-2008 01:19 PM

Rod ends are brassy:

http://forums.pelicanparts.com/uploa...1207084762.jpg

bkreigsr 04-01-2008 04:34 PM

Quote:

Originally Posted by Craig 930 RS (Post 3862878)
I hope to God you don't find what I found:
http://forums.pelicanparts.com/uploa...1207083895.jpg

ouch !
were you able to determine what caused this?
thanks for posting

Bill K

Craig 930 RS 04-01-2008 04:39 PM

General unexplained failure.........

WERK I 04-02-2008 06:28 AM

The particles can come from just about anywhere. The main and rod bearings are multi-layered and contain a brass layer. The rod bushing, rocker arm bushing contains brass.
I would suggest sending the oil out to be analyzed to give you a little more empirical data. The results will end the guessing game you are going through. Brass particles suspended in the oil (if it is brass) is not good news in any event. If it were a newly rebuilt engine, you expect some particles suspended in the oil. The more important question is.....why isn't your filter catching this? Maybe clogged up? Open up the current oil filter and check for particles in the filter media.

930gt-40r 04-02-2008 09:33 AM

You know what sucks about our 930's? The oiling system only filters on the suction side of the oiling sys and not on the pressure side- the reason why the C2 turbos have the filter where the cooler used to be on our motors...

NathanUK 04-02-2008 12:00 PM

To put that into simpler terms...
The oil is filtered on the way out of the engine, not before.

JFairman 04-02-2008 04:33 PM

What sucks is that the oil from the turbo goes back into the oil tank unfiltered, so any carbonized oil from the turbo goes right into the engine.
...unless you install a filter in the turbo oil return line before it drains into the oil tank.


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