As stated in my previous post, I had decided not to change the wearing intake camshaft or rockers and had instead chosen to monitor how the wear progresses over time.
During my first year of ownership, I never went above 6000 rpm. At the end of that year (3070 miles) I re-measured the cam wear and found that it had not progressed.
For my second year, I wanted more data so that when I finally found some progression of cam wear I could have an indication of what the cause was. From that point on, I decided to use the higher part of the rpm range once I waited for 10-20 mins after the coolant temp stabilized.
The leading theories for the cause of the cam wear include low cam hardness (I have not made a test for this), overly tight valve shim setting, and sub-optimal oil temperature. Since my car has two oil coolers, I am quite interested in probing the oil temperature idea.
I have made a poor attempt at measuring the clearance between the rocker and the bucket on the top of the valve stem- I cannot fit even a 0.006" shim between them (I checked on cams which were on the lowest pressure part of their rotation, but I could not easily slide the shim in). This suggests that the valve clearance was not set properly. I am still undeterred in my experiment.
I used metallic tape to secure a thermistor on the bottom of the oil pan and setup an Arduino to log the CAN packet which controls the gauge cluster as well as the thermistor reading to an SD card at a 1 Hz rate. I am aware that my oil temperature measure could be systematically low due to my probing location, but I think that the measure will be good enough. Now that the end of the second year driving season has passed, I took the logged data and prepared histograms.
I looked at the coolant temperature and oil temperature histograms as a function of time since engine start (I also have plots of engine speed and vehicle speed, but these are uninteresting). These plots show how quickly the operating temperatures normalize and what temperature variation there is within each fluid.
The coolant temperature and oil temperature seem to both rise quickly (within 15 minutes of engine start) to their steady state operating range. However, the oil temperature remains quite a bit lower than the coolant temperature. It also has a broader range of temperatures in its final distribution. Later operating times reveal an increased tail in the oil temperature distribution on the high temperature side, but the peak remains at the same point as in early operation time.
I have not measured the cam wear for this second driving season yet, but intend to do so in the spring. At that time, I will block off flow to one or more of the oil coolers and repeat the experiment.
Last edited by Obeisance; 11-26-2016 at 09:17 AM.