Metal in motor oil, origin unknown. Need ideas
#1
Metal in motor oil, origin unknown. Need ideas
I will start with a little car history. This is an 87 924S with unknown mileage. It has been a dedicated drift car/track rat for the last two years. Mostly stock besides a really open intake and exhaust. Oil and filter are changed very regularly, every other outing or so. Now the problem: About 3 events ago I noticed a little bit of very fine metal filings on the drain plug magnet when changing the oil before an event. Kept an eye on things, oil pressure mostly, car ran beautiful except for a noise coming from around the timing belt cover. The next oil change there are even more metal filings on the drain plug magnet. Thinking the noise could be a counter balance shaft problem and the metal may be the related, I pull the counter balance shaft belt and head to the next event with fresh oil and filter. The noise is still coming from the timing cover, sounds like it could be a roller on the timing belt. Oil pressure is solid all day. Get home, pull the dipstick, and it looks like there is glitter in my oil. I pulled the cam box off, and pulled the cam out, everything looks good. I find my water pump pulley has about 10 times the amount of play that should be allowed. Pretty safe to say I found the cause of the (bad roller) noise. I know these engines are prone to rod bearing failure, especially #2, so I proceed to pull the oil pan and pull the rod bearings. They all look surprisingly good. #2 actually looks better than the rest! SO I am kind of stuck on what I should check next. The counter balance shaft belt was off during the last event, so I'm thinking that would rule out a problem there, the cam does not show any excessive wear, and the rod bearings also look good. From what I can see the thrust bearing on the crank looks to be ok also. I can post picks if anyone wants to see, just not tonight. So I need some advice on where to look next, I really do not like glitter in my oil Thanks guys.
Oh and a side note: this engine gets the crap beat out of it, constantly at the red line on the tach, but the oil pressure is always good. I am using the stock gauge set up, which I know is not always accurate, but it shows 0 when the engine is off, between 2 and 3 at idle and 5 when running on the track. It does rise and fall with engine speed as it should.
So please, a little direction would be appreciated. Thanks, and sorry for the long post
Oh and a side note: this engine gets the crap beat out of it, constantly at the red line on the tach, but the oil pressure is always good. I am using the stock gauge set up, which I know is not always accurate, but it shows 0 when the engine is off, between 2 and 3 at idle and 5 when running on the track. It does rise and fall with engine speed as it should.
So please, a little direction would be appreciated. Thanks, and sorry for the long post
#2
Drifting
With the kind of abuse you say you're subjecting that poor motor to, I'd expect to see things start to show up as you've described. I'd suggest you take a look at the oil pump itself. Even though you currently are seeing good oil pressure, that doesn't mean that other parts of the pump assembly aren't starting to wear. Are you hearing more lifter noise? If you have a plugged oil gallery going to the valve train, you might have a problem up there that wouldn't show up on the oil gauge. Did you look at the crankshaft bearings while you were in there?
#4
Rennlist Member
If it's stuck to the magnet, it's steel. If it's "glittery in the oil", it's probably aluminum. It's time to stop running the engine and tear it down. Likely you'll find worn rings and cylinder scoring. Keep running it and those particles will accelerate the bearing wear and it'll throw a rod.
FYI, the cooling system, and your bad water pump, are separate from the oiling system. So while you've discovered another problem, they're not related.
Also, now that you've run without the balance shafts, make sure your oil pickup tube isn't cracked.
FYI, the cooling system, and your bad water pump, are separate from the oiling system. So while you've discovered another problem, they're not related.
Also, now that you've run without the balance shafts, make sure your oil pickup tube isn't cracked.
#5
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Sounds like a bearing is ground up somewhere. Maybe a main or balance shaft bearing? Even though the shafts weren't turning without the belt, the metal shavings have already cycled through the engine and will keep recurring until it's flushed. In any case, I think it's time to tear down the engine. With that much metal in there it needs to be stripped down and flushed.
#6
I know I abuse this poor motor, I have also saved it twice now. I bought this car out of a field where it had been sitting for years because no body could get it running, and brought it back to life. Then a friend was using it to commute to work with and was involved in an accident which tore the left front off the car. That is when it became a dedicated track car. So yes, I abuse this car more than one should, but I have brought her back to life more than once. New rod bearings and connecting rod nuts will be installed. There was not any valve train noise, even in start up. As far as checking the crank bearings I have not, I was working on it at 2am this morning and not sure if I could pull the cradle without damaging anything. I did a compression check before pulling the cam box. All cylinders were within 5psi of each other, all around 180.
#7
I would expect that filings would be from a gear or maybe a roller/ball bearing. Unlikely to be from a plain bearing in my experience. Not intimate enough with the insides of this engine to be more specific, but that might point you in the right direction.
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#8
Race Car
Have you cut up the filter? What color is the glitter? Not sure what kind of oil you are using, I'll spare you the sales pitch, and say that my main bearings were shot and the oil looked like you describe after about 600 miles on a fill of inferior oil (conventional, but marketed as a "race" oil - not). If the "glitter" you describe is gold or copper in color, your main bearings are likely on their way out. I caught mine in time to avoid a catastrophic failure, but I did have to rebuild the bottom end.
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Like said above, copper dust is a bearing. But silver coloring may also be a bearing. Once you wear the copper down enough you hit silverish again. My #3 rod bearing was ground so bad last year that it had completely scraped the copper away on half of it. I had copper and silver (aluminum?) dust everywhere, big chunks too. Your oil pressure hasn't changed at all since this started? I couldn't tell if you pulled the valve cover or not, but if you haven't then check that. I've seen things ground down in there as well (not my car that time!).
#13
An oil analysis would have been the wise first choice. But I have torn into it this far, and everything I have pulled apart would have needed to be checked anyways. I have not cut open the oil filter yet, I will do that tonight when i find my big pipe cutter so I do not contaminate what I find. Can I pull the cradle and check the main bearings without damaging anything? The "glitter" for lack of a better term is silver. I have been running quaker state DEFY supposed to have "boosted zink for extra protection". It's a synthetic blend.
#14
An oil analysis would have been the wise first choice. But I have torn into it this far, and everything I have pulled apart would have needed to be checked anyways. I have not cut open the oil filter yet, I will do that tonight when i find my big pipe cutter so I do not contaminate what I find. Can I pull the cradle and check the main bearings without damaging anything? The "glitter" for lack of a better term is silver. I have been running quaker state DEFY supposed to have "boosted zink for extra protection". It's a synthetic blend.
And what has been the average oil change interval (OCI) in miles over past 2 years?
You indicate: "Oil and filter are changed very regularly, every other outing or so"..
Can we assume the OCI was less than 500 miles each time?
#15
WRONGLY ACCUSED!
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Its awesome when you can cite to yourself.