Followers of this blog will know I periodically send samples of my engine oil to Blackstone Labs for analysis. It’s the only way outside of a teardown to really see what’s going on inside your engine. For instance, after using the Period Correct Tow Pig to tow my car to Las Vegas and back last November, I had a sample of oil analyzed from the truck. The results told me quite clearly that the engine in the truck is almost as good as new. In fact, it’s wear metal levels were below the universal averages for the engine. It’s what gives me the confidence to continue towing around the country with a thirty year old truck.
Since the new engine build on the Buick, I’ve been getting the oil sampled and analyzed with every single oil fill. For the Optima event at NCM, I put a fresh oil change in the car, and then changed it again after the event, so I’d have a snapshot of what a single event might be doing to the engine.
I also had a sample of the transmission fluid analyzed. Since I’ve been battling heat issues with the transmission, I wanted to know just what the heat was doing to the fluid. This will give me information that will allow me to figure out just how hot to let it get, and how often to change it.
So, without further ado, on to the reports themselves. First, the engine oil:
So, I’ve highlighted a few sections here. The report starts with a summary comment box from the lab. I’ve been having this engine checked with them for awhile, so they know the history of this car.
The bit in red is a sample from right before the engine blew in New Jersey in 2017. Sadly, I didn’t get the report back until after the engine failure. What that shows is really high lead and copper. Here’s why that matters: Engine bearings are made of a steel shell with metals layered on top of them. The top layer is usually lead, followed by copper, followed by tin or steel. In most engines, the only place there’s any copper is the bearing shell.
So, if you see lead in your oil, you’re likely seeing some bearing wear. But if you see copper in your oil, it’s time to refresh the bearings, as you’ve worn through the top lead layer. If I’d gotten this result back in time, I probably could have caught the failing #1 rod bearing and saved the engine. Oops. This is why I switched from sampling it once a year to sampling at every oil change.
So, moving leftward to the part in yellow. I’m still seeing elevated lead levels, and have since the new engine was first started. But the copper isn’t moving, and all the other metals like aluminum and iron look fantastic, and lead has been going down in every sample. Where’s the lead coming from? It could be the bearing in the turbocharger, or it could be residual material left in the oil cooler from the failure. I may not have cleaned it well enough. Or it could be main or rod bearing wear.I’m going to have to continue to monitor it. If it continues to go down and copper doesn’t start showing up, I’m probably fine. If it spikes or copper starts to rise, I’ll need to drop the pan and inspect the bearings.
The silicon mentioned in the summary was also a bit high. Silicon in the oil is dirt, and it usually gets in because of a bad air filter. It gets into the intake, and then enters the crankcase via the PCV system. After high silicon showed up in the previous sample, I serviced my K&N air filter, so I hoped silicon would go down. But it didn’t. Why? Well, in this case, if you read my blog entry on the NCM event, I actually had the intake tube fall out of a coupler, and the engine was pulling unfiltered air for a bit of the day. That certainly sucked in some dirt, and that showed up in the oil.
Finally, at the end of the event, I noticed some pretty low oil pressure when the oil got hot. This report pretty much confirms it was oil viscosity related. The highlight in green shows this oil was out of spec for a 5w40 at 210 degrees. The previous sample was the same oil, had a longer run on it, and was in spec. There is no water or fuel dilution, so this particular batch of the Motul was just too thin. The lack of elevated metals like aluminum and iron tells me that while the pressure got low, it didn’t hurt the engine.
I changed the Motul out for a Castrol 5w50. It will be interesting to see the difference on the next report.
So, the verdict is to keep watching. Nothing serious. Hopefully that lead will continue to fall, but the engine appears to be healthy.
Onward to the transmission!
Now, since this is the first sample I’ve ever had taken on this transmission, there’s no history, so not much of a story to tell yet. It is comparing favorably with the universal averages, though. For the time being, though, I was concerned about the viscosity numbers. I pitted the car at NCM when the transmission fluid temps hit 200 degrees. This is telling me that the oil was still stable. Which means I can probably raise my warning light to 220 or so and get another lap or two per session in.
The high insolubles are typical for a new transmission. Break-in lube and clutch material takes a while to work it’s way out of the parts and into the filter.
So all in all, not a very interesting report, which is a very good thing. The driveline is healthy, I can continue to beat on it. I have a few autocross events in July and the KYSCCA Time Trial Regional on August 4. I’ll probably change the fluids and do another sample after that, so stay tuned!