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Old 04-17-2018, 08:18 PM
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rockhouse66
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Default Oil Analysis Question

My 2004 C2 Cab is running great. I drank all the Kool-Aid and did all the usual upgrades almost 10,000 miles ago. Car has 79K miles on it now. The last two Blackstone analysis reports noted that the aluminum content is higher than the iron content, which is apparently of some concern. The aluminum runs 7 or 8 and the iron runs 4 or 5. I assume the Units are PPM? Anyway, should I actually be concerned? Is the aluminum an indication of bore scoring or ???

Car uses zero oil through the 3000 miles oil change period and no smoke ever. Running LiquiMoly 5W40.
Old 04-17-2018, 09:49 PM
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joe-1972
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Rockhouse66, get in touch with Jake Raby... He might be able to point you in the right direction... Also Lake Speed JR.
Old 04-17-2018, 10:24 PM
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rockhouse66
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Joe
I'm sure they would have an opinion, so thanks for the suggestion.. However, I have not involved them or paid them to do anything for me as of yet so I am not comfortable soliciting their professional opinion. I am hoping some other RL'er will have already crossed this bridge on their own or with input from a pro and would be able to comment.

Where does aluminum come from in this engine? I can't imagine it is the chain slapping the case or I would already have big issues.
Old 04-18-2018, 06:59 AM
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Silk
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The block is aluminium and cilinder surfaces are Lokasil which is an Al-Si alloy. Basically it is a region rich in Silicon. During the casting process and more specific the cooling down of block the silicon will precipitate and forma grains/particles which reinforce the aluminium matrix.

By honing and further finishing the cilinder walls a particular surface structure is obtained which is both durable and will provide low friction. The silicon particles tend to stick out a bit of the matrix, they are very hard, so they contribute to the durability of the surfaces. Because the particles stick out a bit it provides a certain surface structure which retains a good oil film, which in return is beneficial for lower friction.

A very smart way of manufacturing a block. And as long as operating parameters (temperature, oil viscosity, oil film strength, etc) are within certain range it works out damn fine. However also a vulnerable construction. Due to extreme temperatures and oil film strength goes down. Piston and rings will cause higher forces on the surface and Si particles can be ripped out of the matrix. Microscopical damaging of the cilinder wall. The ripped out particles cause further abrasive wear. A start for an ever increasing wear pattern which will eventually end in bore scoring and/or cilinder failure.

Not in perspective with the above doom scenario it is plain normal to find some traces of aluminium in the oil as an engine will always wear a bit. To my knowledge the values of your sample look normal to me. However I am no expert.

Every car has its own fingerprint when it comes to oil analysis. I think it is more important to keep an eye on trends. And use the oil analysis to find a reasonable interval for oil changes.

When something is really wrong an oil analysis will probably not save you because it will be too late, in case not you will most probably much higher amounts of Al or Fe. Real anomalies.

Go drive and enjoy!!!

Last edited by Silk; 04-18-2018 at 08:00 AM.
Old 04-18-2018, 09:00 AM
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Slakker
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It is interesting that the the aluminum is higher than the iron. 7ppm is still within acceptable range though so I wouldn't worry about it.
Old 04-18-2018, 09:16 AM
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Silk
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Why would the Al and Fe readings be to a certain extent correlated?
Old 04-18-2018, 09:20 AM
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rockhouse66
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Originally Posted by Silk
Why would the Al and Fe readings be to a certain extent correlated?
That is sort of my question too. I think Blackstone's comment is based on the fact that the analysis came out 5/5 on aluminum/iron on one analysis, then the next two were 8/5 and 7/4 so the aluminum has taken a little bump up and I am trying to ascertain what this could mean.
Old 04-18-2018, 09:40 AM
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For me they are not necessarily correlated. Probably there are wear scenarios where both Al and Fe will go up together.
Well, I would simply ignore these small fluctuations. Unless Fe, Al, Cu will rise significantly. And then I mean real big increases such as 30 or more. Really red flags.
See the analysis as a trend spotter.
.
Old 04-18-2018, 03:42 PM
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Chris(MA)
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m96 cams run direct in the head and cam covers, no bearings. So steel on aluminum, considering there are 4 cams with multiple bearings on each cam, also the bucket followers also run straight in aluminum sub assembly, there are 24 of those too.

I wouldn't worry at this point.



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