Motor Oil Wear Test Results – Caution, VERY long

[540 RAT]

I think folks would generally agree that the most important thing a motor oil does, is prevent metal to metal contact. Everything else it does comes after that. Liquid oil is incompressible, no matter what the viscosity. So, in the places and conditions inside an engine where you have enough flow between parts to maintain a presence of liquid oil without it being squeezed away, all oils will offer similar protection in preventing metal to metal contact.

But, under extreme loading and/or heating conditions, as well as at flat tappet interfaces, distributor gear interfaces (particularly those with high volume oil pumps), BBC lifter bore primary thrust surfaces (due to tilted pushrods and often offset pushrod seats in the lifters, along with high spring pressures), and cold start-up where oil has run off, to name just a few examples, you can be left with only a very thin “film of oil” to prevent metal to metal contact, rather than enough flow to have a presence of liquid oil.

In these cases, an oil’s “load carrying capacity/film strength” is all-important to prevent wear. And in this regard, oils vary greatly. But finding this data for comparison is nearly impossible because most oil companies do not publish this type of info. And when you can on occasion, come up with some data, you never know if you can trust its accuracy because it will typically be advertising based.

I consider “load carrying capacity/film strength” to be the first thing to consider when choosing a motor oil to run. Detergent/dispersant levels for anti-deposit buildup/anti-sludge, TBN acid neutralizer levels, anti-foaming agent levels, and NOACK volatility percentages, etc, etc, all come after that.

So, I bought an oil “load carrying capacity/film strength” tester. This gives me the capability to test and compare various oils head to head, using the exact same test equipment and the exact same test procedure. That way I’d know the truth first hand. The testing was performed in Southern California during February and March 2012.

As far as I know, I’m the only one who has ever done such a wide ranging motor oil wear test. I went to all this trouble because I wanted to “KNOW” how good various oils are, rather than have to essentially guess. I really only did this testing for my own knowledge, and to share it with a handful of car buddies. But a few of those car buddies talked me into posting the info on some of the Forums, so that everyone could get a chance to see all the data. So, the test results are shown below, for those who might like to see them.

I’ll make it perfectly clear right up front. My testing was not done inside a running engine. I tested 44 different oils, and testing that many oils in a running engine was simply not practical, not to mention that there would be too many variables to have a true apples to apples comparison. All my testing was done with the oil tester. So, for those who put no value on data gathered from “Lab” testing, feel free to close out now, and go on to the next topic. For everyone else, read on.

My tester spins a test ring bathed in oil at 456 rpm (7.6 rev/sec), and a test specimen is “gently” brought down into contact with the spinning ring. A load is then “gently” applied to the test specimen and is “gradually” increased, so as not to suddenly punch through the oil film, and also to allow the zinc a bit of time to get hot and become effective.

At the conclusion of each 30 second test, the wear scar that is generated, is carefully measured with the aid of a magnifying glass to maximize accuracy. Then the psi that the oil supported, is calculated, which gives the value of its “load carrying capacity/film strength”. All the oils are of course subjected to the exact same test procedure, so they all have the same opportunity to perform as well as they can.

NOTE: The test results are intended to enlighten and inform, not to offend. And they were generated without bias towards any particular brand or viscosity. To prove that there was no bias here, my long time “oil of choice” Royal Purple, did not show up all that well. And I did not hesitate to show that. For better or worse, the numbers simply are what they are, and speak for themselves.

I have a copy of the official ASTM D 2782, the Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Fluids (Timken Method). And for the record, ASTM D 2509, is the Standard Test Method for Measurement of Load-Carrying Capacity of Lubricating Grease (Timken Method). They are NOT the same test spec.

The ASTM D 2782 calls for testing the oil at 100*F, yes 100*F, NOT 100*C. Testing at that temperature is completely worthless in my mind. Because that is really just a hot “room temperature”, and is not hot enough to be representative of actual oil temperatures inside a running engine. And for example, 0W30 and 10W30 are not even the same viscosity at room temperature, but they are rated the same viscosity by the time they reach 212*F (100*C). So, in order to obtain the most valid data possible, I did all the oil tests at 230*F, which has all the same hot category multi-viscosity oils at the “same” viscosity, and is representative of oil temps inside a running engine. That being the case, I did not precisely follow what I consider the useless ASTM D 2782 standard.

Note:
*** The test procedure I used was developed and refined to obtain the best possible repeatability, which ensures the most accurate test results possible. Once I made the final revision to optimize the procedure, testing began and the exact same test procedure has been used over and over again for all the following tests.

*** I used 5W30 Castrol GTX conventional oil during the entire test procedure development phase, in order to keep things consistent. During that time, I tested it both HOT (230*F) and COLD (mid 60’s F). And it’s COLD “Load carrying capacity/Film strength” was about “TWICE” as high as its HOT capability. So, the hotter and thinner the oil, the lower its “Load carrying capacity/Film strength”.

*** The testing here only evaluates “Load carrying capacity/Film strength”, but does NOT test an oil’s slipperiness/friction reducing qualities. Load carrying capacity and slipperiness do NOT necessarily go hand in hand. For example, if we were to fill our engines with thick old school STP Oil Treatment, we’d have much higher “load carrying capacity/film strength”, but the HP would plummet due to all the extra viscous drag. Therefore, the testing here does NOT provide any information regarding HP increasing capabilities. But in the future, I do plan on doing a separate oil test on the “slipperiness/friction reducing qualities” of each of the oils tested below. So, stay tuned for that.

*** I was able to directly compare 20 wt type oils, 30 wt type oils, 40 wt type oils and 50 wt type oils because even at 230*F, all the oils stayed on the spinning test ring nicely without flinging off. Therefore, no viscosity had any advantage over another.

A few overview highlights of the results:

*** The High Performance and Racing oils did NOT dominate all the top ranking positions as expected. In fact, contrary to popular belief in the Hotrod and Racing world, simply having high levels of zinc/phos was absolutely NOT a guarantee of high “load carrying capacity/film strength”. Some high zinc/phos oils had excellent test results, while other high zinc/phos oils had only fair test results.

*** This testing has clearly shown that a particular oil’s “load carrying capacity/film strength”, is NOT determined just by its zinc/phos levels, but rather, it is determined by the oil and its additive package “as a whole”. So, if people choose an oil strictly based on its zinc/phos levels, they could easily end up having a “LOT LESS” protection than they think they have.

*** This testing has clearly shown that an oil’s viscosity is also absolutely NOT an indicator of its “load carrying capacity/film strength”. Among the 44 oils tested here, 50 wt type oils ranked from 6th to 40th, 30 wt type oils ranked from 1st to 44th, and 20 wt type oils ranked from 10th to 35st. So again, an oil’s “load carrying capacity/film strength” is determined by the oil and its additive package “as a whole”, nothing else.

*** This testing has clearly shown that you simply CANNOT PREDICT an oil’s “load carrying capacity/film strength” by looking at its specs or its viscosity. You can only determine that capability by performing some type of actual wear testing, as I’ve done here. But, there are of course other wear test methods that can be used as well, such as the 4 Ball Wear Test which is somewhat popular in the oil industry. Though I have only seen Amsoil list results from that type of wear testing. My tester and the 4 Ball wear tester are in no way attempting to duplicate engine internals. Instead, they are designed to test oils directly against each other in a controlled and repeatable manner.

*** The latest “LOW” zinc/phos API certified oils, both synthetic and conventional, performed WAY better than expected. In fact, they are so good that their capability has surpassed most of the traditional high zinc/phos High Performance and Racing oils.

*** “Low cost” conventional API certified oils performed WAY better than expected.

*** Lucas and Valvoline Racing oils performed very well.

*** Royal Purple High Performance, Racing and street oils generally performed below expectations.

*** Brad Penn High Performance and Racing oils performed below expectations.

*** With that said, there are no BAD oils here. Some are simply better than others in terms of “load carrying capacity/film strength”. Those that have a higher capacity, offer a higher margin of safety than those with a lower capacity.

Motor Oil Wear Test Results and Ranking

*** The higher the psi result, the higher the “Load carrying capacity/Film strength”, and the better the oil is at preventing wear.

*** All oils were tested at 230* F (representative of actual running temperature).

*** Multiple tests were performed on each oil, and those results were averaged to arrive at each oil’s final value shown below. Differences between oils of 10% or less, are not significant, and oils within that range can be considered approximately equivalent.

*** All oil bottles were thoroughly shaken before the samples were taken. This ensured that all the additive package components were distributed uniformly throughout all the oil in the bottle, and not settled to the bottom.

*** All oils are full synthetic unless otherwise specified.

*** All oils are suitable for street use unless otherwise specified.


Oil categories:

*** Over 90,000 psi = OUTSTANDING protection

*** 75,000 to 90,000 psi = GOOD protection

*** 60,000 to 75,000 psi = MODEST protection

*** Below 60,000 psi = UNACCEPTABLE protection



********** OUTSTANDING PROTECTION ************


1. 5W30 Pennzoil Ultra, API SM = 115,612 psi
I have not been able to find this oil with the latest API SN certification. The bottle says, “No leading synthetic oil provides better wear protection”. For once, a product’s hype turns out to be true.
zinc = 806 ppm
phos = 812 ppm
moly = 66 ppm

2. 10W30 Lucas Racing Only = 106,505 psi
zinc = 2642 ppm
phos = 3489 ppm
moly = 1764 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

3. 5W30 Mobil 1, API SN = 105,875 psi
zinc = 801 ppm
phos = 842 ppm
moly = 112 ppm

4. 0W30 Amsoil Signature Series 25,000 miles, API SN = 105,008 psi
zinc = 824 ppm
phos = 960 ppm
moly = 161 ppm


******* 10% below number 1 = 104,051 psi ********


5. 10W30 Valvoline NSL (Not Street Legal) Conventional Racing Oil = 103,846 psi
zinc = 1669 ppm
phos = 1518 ppm
moly = 784 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

6. 5W50 Motorcraft, API SN = 103,517 psi
zinc = 606 ppm
phos = 742 ppm
moly = 28 ppm

7. 10W30 Valvoline VR1 Conventional Racing Oil (silver bottle) = 103,505 psi
zinc = 1472 ppm
phos = 1544 ppm
moly = 3 ppm

8. 10W30 Valvoline VR1 Synthetic Racing Oil, API SL (black bottle) = 101,139 psi
zinc = 1180 ppm
phos = 1112 ppm
moly = 162 ppm

9. 5W30 Chevron Supreme conventional, API SN = 100,011 psi
This one only costs $4.29 per quart.
zinc = TBD
phos = TBD
moly = TBD

10. 5W20 Castrol Edge with Titanium, API SN = 99,983 psi
zinc = TBD
phos = TBD
moly = TBD
titanium = TBD


11. 20W50 Castrol GTX conventional, API SN = 96,514 psi
zinc = 610 ppm
phos = 754 ppm
moly = 94 ppm

12. 30 wt Red Line Race Oil = 96,470 psi
zinc = 2207 ppm
phos = 2052 ppm
moly = 1235 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

13. 0W20 Mobil 1 Advanced Fuel Economy, API SN = 96,364 psi
zinc = TBD
phos = TBD
moly = TBD

14. 5W30 Quaker State Ultimate Durability, API SN = 95,920 psi
zinc = 877 ppm
phos = 921 ppm
moly = 72 ppm

15. 5W30 Castrol Edge with Titanium, API SN = 95,717 psi
zinc = 818 ppm
phos = 883 ppm
moly = 90 ppm
titanium = 44 ppm

16. 10W30 Joe Gibbs XP3 Racing Oil = 95,543 psi
zinc = 743 ppm
phos = 802 ppm
moly = 1125 ppm
NOTE: This oil is suitable for short term racing use only, and is not suitable for street use.

17. 5W20 Castrol GTX conventional, API SN = 95,543 psi
zinc = TBD
phos = TBD
moly = TBD
NOTE: Oil numbers 16 and 17 were tested weeks apart, but due to the similarities in their wear scar sizes, their averages ended up the same.

18. 5W30 Castrol GTX conventional, API SN = 95,392 psi
zinc = TBD
phos = TBD
moly = TBD

19. 10W30 Amsoil Z-Rod Oil = 95,360 psi
zinc = 1431 ppm
phos = 1441 ppm
moly = 52 ppm

20. 5W30 Valvoline SynPower, API SN = 94,942 psi
zinc = 969 ppm
phos = 761 ppm
moly = 0 ppm

21. 5W30 Valvoline Premium Conventional, API SN = 94,744 psi
zinc = TBD
phos = TBD
moly = TBD

22. 5W20 Mobil 1, API SN = 94,663 psi
zinc = TBD
phos = TBD
moly = TBD

23. 5W20 Valvoline SynPower, API SN = 94,460 psi
zinc = TBD
phos = TBD
moly = TBD

******** 20% below number 1 = 92,490 psi ********

24. 5W30 Lucas conventional, API SN = 92,073 psi
zinc = TBD
phos = TBD
moly = TBD

25. 5W30 O'Reilly (house brand) conventional, API SN = 91,433 psi
This one only costs $3.99 per quart.
zinc = TBD
phos = TBD
moly = TBD

26. 5W30 Red Line, API SN = 91,028 psi
zinc = TBD
phos = TBD
moly = TBD

27. 5W20 Royal Purple API SN = 90,434 psi
zinc = TBD
phos = TBD
moly = TBD

28. 5W20 Valvoline Premium Conventional, API SN = 90,144 psi
zinc = TBD
phos = TBD
moly = TBD


************ GOOD PROTECTION **********


29. 30 wt Castrol Heavy Duty conventional, API SM = 88,089
zinc = TBD
phos = TBD
moly = TBD

30. 10W30 Joe Gibbs HR4 Hotrod Oil = 86,270 psi
zinc = 1247 ppm
phos = 1137 ppm
moly = 24 ppm

31. 5W20 Pennzoil Ultra, API SM = 86,034 psi
I have not been able to find this oil with the latest API SN certification.
zinc = TBD
phos = TBD
moly = TBD

32. 5W30 Royal Purple API SN = 84,009 psi
zinc = 942 ppm
phos = 817 ppm
moly = 0 ppm

33. 20W50 Royal Purple API SN = 83,487 psi
zinc = 588 ppm
phos = 697 ppm
moly = 0 ppm

34. 5W30 Mobil 1 Extended Performance 15,000 mile, API SN = 83,263 psi
zinc = 890 ppm
phos = 819 ppm
moly = 104 ppm

35. 0W20 Castrol Edge with Titanium, API SN = 82,867 psi
zinc = TBD
phos = TBD
moly = TBD

******** 30% below number 1 = 80,928 psi ********


**************** MODEST PROTECTION ************

36. 5W30 Royal Purple XPR (Extreme Performance Racing) = 74,860 psi
zinc = 1421 ppm
phos = 1338 ppm
moly = 204 ppm
NOTE: This particular bottle of oil was just opened, but was out of a 3 ½ year old case.

37. Brad Penn, Penn Grade 1 Nitro 70 Racing Oil (semi-synthetic) = 72,003 psi
zinc = TBD
phos = TBD
moly = TBD

38. 0W30 Brad Penn, Penn Grade 1 (semi-synthetic) = 71,377 psi
zinc = 1621 ppm
phos = 1437 ppm
moly = 0 ppm

39. 10W30 Brad Penn, Penn Grade 1 (semi-synthetic) = 71,206 psi
zinc = 1557 ppm
phos = 1651 ppm
moly = 3 ppm

40. 15W50 Mobil 1, API SN = 70,235 psi
zinc = 1,133 ppm
phos = 1,168 ppm
moly = 83 ppm

******** 40% below number 1 = 69,367 psi ********

41. 5W30 Motorcraft, API SN = 68,782 psi
zinc = 796 ppm
phos = 830 ppm
moly = 75 ppm

42. 10W30 Royal Purple HPS (High Performance Street) = 66,211 psi
zinc = 1774 ppm
phos = 1347 ppm
moly = 189 ppm

43. 10W40 Valvoline 4 Stroke Motorcycle Oil conventional, API SJ = 65,553 psi
zinc = 1154 ppm
phos = 1075 ppm
moly = 0 ppm

44. Royal Purple 10W30 Break-In Oil conventional = 62,931 psi
zinc = TBD
phos = TBD
moly = TBD

******** 50% below number 1 = 57,806 psi ********


Summary:

Readers can of course do whatever they want with these results. But for me, seeing is believing. The smallest wear scars created by the best oils, were quite impressive. So, now I’ll be choosing oils for my Hotrods and daily drivers from the OUTSTANDING PROTECTION category, in order to have the highest level of protection. There are plenty of different oils in this category, 28 of the 44 to be exact, and they all have 90,000 psi or higher capability. After reading this report, you may never think about motor oil the same way again.

[PackardV8]

Very interesting and thanks for sharing.

Question - specifically what makes the Lucas, Valvoline et al Racing Oils not suitable for longer term street use?

jack vines

[sanfordandson]

catalyic converter damage from high zinc content i believe.

[mod7]

I was told by Valvoline that the difference between the non street legal oil and the VR-1 was that the Non street legal oil has no detergents, and if used for extended periods of time can build up more then standard detergent oil.

[CREngines]

i applaud your effort in performing this test.
We have had very positive results with the Lucas racing oil as well.
We didnt have much luck with the
Brad Penn and that lines up with what you found.

[levisnteeshirt]

i used to be a WD for Pro Blend ,, thanks for posting ,,,, things like this interest me , have you tried any additives against this test ?

for oil to shear , the oil has to not slip itself on the metal surface its protecting , this is usually where it fails , the penzoil must bond to the metal more efficiently

the pro blend test also heats the oil ,, the gooey sticky stuff isn't so sticky after its heated ,,

[mach1charlie]

Thanks for posting, and now everyone will ask you to test there oil... aaahhh Rotella 15/40 ?

[GM-DR]

Thanks for all your hard work!!!!!verrry interesting!!!!! Would Love to see some numbers on Joe Gibbs XP1, Rotella 15-40, and Rotella 5-40 synthetic? Did you find in general that synthetics outpeformed conventionals?

[Blown BBC]

Very interesting, I guess I should have not switched from Valvoline VR1 to Brad Penn, although its hard to tell because I run 20w50 or straight 50 and you didn't test much of that weight. I would like to see the Valvoline VR1 in 20w50 and 50, Brad Penn in 20w50 and Amsoil in zrod 20w50. Any chance you can add those to your list? I will send you a Brad Penn 20w50 if you want. Thank you for the results.

[n5ifi]

What does the test mean in a race motor?
What part of a motor would this test be applicable to?
How does that pressure from your test apply to an engine bearing which probably has more surface area than your test and is pressure fed?
Was your test made with oil on the suface of the metal alone or was it pressure fed?
I've been a "Bobs the oil guy" member for a while and seen so many test it would make your head spin.
I've run the best oils and I've run the worst oils in your test and never found any real difference in an motor oil based on this type of wear test.
I'm not saying it isn't true, I've just personally never seen it.
I'll give an example. I've got a buddy of mine that runs a solid lifter cam, 466, 12:1 compression and goes through the traps in the quarter at 7200. He runs Motorcraft 5-30 oil and has now for 7 years changing oil 1 time every year wether it's needed or not. Now his oil pan is 8 quarts so......
The motor has never been apart and has made hundreds of passes and that oil ranked low on your scale. I have another buddy that ran Royal Purple oil (not sure about the weight) and never changed it or the filter for over 5/6/7 years (he is a mechanic and own his own station). He finally ruined the motor by running it low on oil. His son checked it and didn't know what he was doing. That motor was never hurt and 5+ years on a racing motor is.....well good I would say. I have to hear him bragging about it all the time. We give him hell for ruining a perfectly good engine by running it out of oil. Both of these guys are bracket racers and race often and believe me do very little maintenance. These cars are never torn down during the off season and inspected and the valve springs are never even realsed during the winter. I do more than they do on their cars. I admit those were not the most demanding situatons but there was no roller cam in the bunch so there was metal parts making contact that wear not rollerized.
Your test if I remember right is a round piece of metal spinning and another piece is pulled or plunged into the rotating part etc.etc or pulled down onto the metal with a lever or something of the sort. Is that right?

[Greenlight]

Thanks for all of your hard work and for sharing the results. I've spent a lot of time on the internet trying to find this information. It is virtually impossible to find anything.

Also, thanks for using 230 F instead of 100 F. This gives the test real world meaning.

As in every test it usually leaves you with more questions. You indicated that you did initial set up testing at room temperature and the results were approx. double that of the high temp. test. This begs the question as to what happens when the temperature is increased even more.

I am interested in learning more about the performance at even higher temperatures. In many (mine in particular) high RPM engines the big end of the rod distorts at high rpm and cause the bearing clearance to significantly reduce. When this occurs, the oil temperature in the bearing increases by a substantial amount. When the temperature increases the viscosity reduces, and the film strength follows suit.

A typical oil temperature increase in the bearing may be 200 F with the nominal (as assembled) clearances, but when the rod distorts and the clearances are reduced the oil temperature increase in the bearing may be 400 F more. The oils performance at these temperatures (in my opinion) is what separates a good oil from a great oil. Synthetic oils boil at a much higher temperature than pure dino oils and this makes them superior in many ways for racing applications.

The calculated connecting rod max. film pressure in my engine is ~17,000 psi and the main bearings are ~ 9,000 psi. All of the oils listed would easily meet the requirements at 230F. Because of rod distortion at high rpms I have problems with the rod bearings holding up and am getting metal to metal contact (sometimes complete bearing failure) with my current oil.

I know I may be asking for a lot, but could you test one or two of the oils in your test at a few temperatures (preferably high temperatures), so a film strength vs. temp. curve can be obtained? This general curve could act as a rough template for all of the oils in your test.

Thanks again for all of the very valuable information that you have shared.

[Cogburn]

Interesting considering that my engines running VR1 look much worse than the ones running Brad Penn.

So far Brad Penn makes everything else look bad(methanol injected engines). Also those low zinc oils seem like they don't do so well with roller lifters. I wouldn't use any of the top oils on this list for a solid roller cam engine.

Maybe I'm just behind the times and the oils listed all got a lot better all of a sudden...

[Bob Hollinshead]

I wish some rotella straight 30 and 15-40 results would have been thrown in there for comparisons.

[Milan..]

Thoroughness of your testing is excellent! Thanks for all the hard work!

[Cedarmachine]

I use O Riley generic oil in all our daily drivers and in my dually with Howard's Zinc additive. When it goes on sale for $2 a quart, I buy at least 6 cases. Honestly, I thought it probably was a good oil,but I bought it based on price. I may just start running this in some race engines as well, with an additive.

Great info, thanks for the effort.