Paradise Garage
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© 2003 Brian F. Schreurs
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Even we have a disclaimer.
Blackstone Labs has been increasingly concerned with the levels of our copper; the first report, they noted "Copper tends to read high in new GM engines until quite a few miles have been accumulated -- we've seen it linger past 30,000 miles." So we started out fairly relaxed about the situation; this changed with the second report, which read "We don't think copper should have increased as much as it has. This copper level is either from an additive or a poorly wearing bronze or brass part." Of course, we're not using an additive, so we started to grow concerned. We sent an e-mail asking for a clarification on this evaluation, but never got a response. Finally, the third analysis included, "If you're not [using an additive], it's time to change out this oil. The copper level is causing the wear to be too abrasive for further use. The copper may be coming from a poorly wearing bronze or brass part."
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We found every online test we could, and so far our own results don't seem out of line for the LS1 engine. In fact, our car seems to be pretty typical. For this reason, unless the results become far more alarming, we intend to disregard the high concentrations of copper as an inevitable consequence of testing on the LS1 engine.
We finally had a chance to discuss these findings with an analyst at Blackstone, and they agreed that these results seem to be fairly typical for LS1s, while still pointing out that they were considered high. However, they do not believe there is great cause for alarm so long as our iron and lead numbers do not suddenly rise. We asked why copper from an additive is okay but copper from the engine is bad, and they explained that engine copper is in its pure form -- little shards of metal floating around. However, copper from an additive is bonded as part of a molecule and lacks sharp edges. This kind of weird thing can happen at the particulate level.
The data in this table is hardly the nice smooth curve we'd like it to be -- in fact, it's so scattered that we didn't bother with presenting a graph along with the table. What we need is more information so we can weed out the irregular cars and determine what a typical LS1 is like.
To keep the idea of "contamination" in perspective, keep in mind that 81 ppm is 0.000081% of the volume of oil; that is, out of a full crankcase of oil, there's less than half a milliliter of copper in it -- about four grams' worth.
If you own any LS1-powered car and have conducted an oil analysis using any oil at any point in the car's life, please let us know about it so we can include your data in this study.
A while back, we got our hands on a copy of an SAE Technical Paper, 1997 GM 5.7 Liter LS1 V8 Engine, number 970915, from 1997. It provides a detailed description of the engineering behind the LS1 engine, including the type of metal used in most of the parts. Far and away the most likely candidate for copper shedding seems to be the engine's cam and crank bearings. The number three crank bearing, in fact, was designed specifically "to minimize the effect of thermal growth differences between the aluminum block and iron crankshaft." In other words, it's got a tough job: if the block and crank disagree on clearances, this bearing loses. Bearing wear is also consistent with enthusiasts' observations when they tear down their engines.
Our guess proved close. At an SAE conference this year, we met up with an R&D engineer from General Motors. He checked into the copper issue for us, and the answer is: the camshaft bearings. They shed copper during break-in (and apparently they take a while to break in, eh?). It's normal and won't cause any problems.