Oil Analytical Testing (For the D)

For the longest time, I have wondered about the oil we use.  When we first started this adventure, I talked to some friends who were developing a biological sourced oil.  The mantra of those engineers was the base oil is not the issue, true wear protection is in the additives.  This brings me back to the very beginning of us Lemons racing.  At that time I had clients in both the biofuels and bio-oils.  The initial utopian thought was to offer us running cars as a test bed for their products, and we would get sponsors.  That never happened.  However, what we are left with is a green theme, that mutated to Z-lime, and I have completed digression from my oil tale.

Back to oils,  I have always had lingering questions about the oil we use.  After several gyrations we have gravitated to quantity over quality, and a current practice is to exchange the oil after every major session.  This translates into going through 24 quarts of oil over a typical weekend.  After repeatedly acquiring that much oil, I start to wonder is this a wise practice.  Well, after this last Thunderhill race we collected an oil sample from both of the cars and sent it for testing.  I did receive the results for the D and will update with we get the Z numbers.

So for the D here is the report:

Reviewing this report the wear metal, contaminant metals, and multi-source metals are not remarkable.  That is a good thing and means we are not seeing excessive engine wear that is being put into the oil.

When we look further to the right on the report's first table, it is good to see some elevated levels.  Many of the last 6 metals, are placed into the oil for increased wear protection and dispersant properties.  The types and amount of these metals are what those oil engineers were talking about and are truly what separate the various types of conventional oils.  The two primary wear protective actors are the phosphorus and zinc.  The phosphorus coats the metal providing a protective layer for those areas where there is metal to metal contact.  The zinc coats and also provide mechanical lubrication for the metal contact points (think graphite).  As for the appropriate level the literature is a bit unclear as a result of large variation in engine designs.  What is known is no added benefits are seen in any application with phosphorus and zinc levels above 3,000 ppm.

To review where we are, I have developed the table below comparing various oil products.  The baseline of the oil we lasted used was Castrol 20w-50 (at $15 for 5 quart).  To augment the zinc and phosphorus levels, we have been adding about 3 oz of Rislone ZDDP at every exchange.  To compare this I found two competitive oils, Valvoline race oil and Pennzoil GT competition oil (for NASCAR) and we can compare them below.

Additive metal concentrations

Metal	Castrol 20w-50 oil (in ppm)	Valvoline Race 20w-50 (in ppm)	Pennzoil GT Competition 20W-50 (in ppm)	Castrol      20w-50 with   3 oz additives      (in ppm)
Molybdenum	0	1	114	75
Magnesium	0	867	7	25
Calcium	167	2,815	2,932	2,153
Phosphorus	830	1,105	2,351	1,262
Zinc	760	1,200	2,342	1,443

Reviewing these results, it looks clear that even after the 6 hours of running we still have a good amount of the additives available, so we are doing well so far.

Then when we look further into the report, we have the contaminants and fluid properties.  The obvious issue is the amount of fuel in the oil.  For anyone who goes under the car this is not a complete surprise.  What is fun is to see the actual level and then read the technician response on why the fuel is there, "may be caused by component faults related to injectors, ignition/timing, or excessive blow-by.  Additional causes include heavy throttle application...."  Guilty.

What I find interesting, is that even with the large amount of fuel in the oil we still have a decent amount viscosity.  The Castrol we run is spec at 18.1 cSt, so yes degraded, but is at the level of what a 10-30 weight oil.  The other nice item is the Oxidation of 4 abs/cm.  This tells us the oil is still oil. So, even running the Castrol it has not broken down to a liquid sludge.

In a nut shut we still have oil after a 6 hour run.  The report tells us we are not seeing excessive component wear, and the additives are at a good level.  Then, with the amount of fuel, our practice of exchanging the oil out at every major run seems to be valid.  So, all is well.

 I look forward to seeing what the Z tells us.