NOACK Volatility and Four Ball Wear Tests
I'm back again with more questions after doing more research about the oil I will put in my '77 300D diesel engine after the next oil change and whether to change to synthetic or not.
I looked at your specs for various oils and did not see either the NOACK Volatility Test (oil heated to 250 C/500 F for one hour, measure the remainder that has not evaporated, used as a measure of oil consumption) or the Four Ball Wear Test (one ball bearing rotated against three fixed ball bearings, rotating ball bearing is forced against the fixed bearings at a specified preassure, at 150 C, at a specified rpm for one hour, measure the scoring on the bearing, determines the wear on sliding parts like overhead camshaft to rocker arm and piston to cylinder wall).
What do you think of these tests? It seems to me that when evaluating the top oils in a certain category to determine one to choose that the NOACK and Four Ball tests may be a determining factor when other specs are close (such as viscosity index, pour point, flash point, TBN, HT/HS spec, phosphorous/zinc/sulfated ash content, etc., etc.).
I would like your comments about the following info/specs I found about diesel oils from the Motor Oil Bible by Michael Kaufman and the GoSynthetic web site (these oils also have API S ratings for gas engines).
NOACK Volatility Test, ASTM D-5800, Mar. 2000, all 15W-40 oils:
Brand and % Evaporated
Amsoil synthetic diesel/marine 6.60
Valvoline Premium Blue 11.00
Chevron Delo 400 11.70
Shell Rotella T 13.01
Mobile Delvac 1300 13.38
Mack Bulldog 13.96
Four Ball Wear Test, ASTM D-4172B, Jan. 1995, 40 kg pressure @ 150 C, 1800 RPM for 1 hour, all 15W-40 except Mobile Delvac synthetic 5W-40 and 1 Tri-Syn 15W-50 using different testing procedures:
Brand and Score Dia. in mm
Amsoil synthetic diesel/marine .35
Mobile Delvac 1300 .619
Chevron Delo 400 .620
Valvoline Premium Blue .625
Shell Rotella T .636
Mobile Delvac 1 synthetic 5W-40 .646
Mobile 1 Tri-Syn 15W-50:
tested at 60 kg pressure @ 150 C @ 1800 RPM for 1 hour
result: score dia. 1.474 mm
tested at 40 kg pressure @ 150 C @ 1200 RPM for 1 hour
result: score dia. .920 mm
I know that this is a mixed comparison since Amsoil synthetics are compared to dino oil for all but two oils and different test procedures for Mobile 1. However, this is the info/specs I found at the above mentioned sources (which are Amsoil associated to a degree). I will also say that the Motor Oil Bible's extensive comparison tables do not list Amsoil as the best oil in certain categories using an algorithm the author created to arrive at a ranking score based on the specs available (Red Line, NEO, Philips 76, Exxon, and Kendall topped Amsoil in several popular categories, Amsoil was tops in a couple of other categories - to show objectivity and a lack of bias toward Amsoil since the info above came from sources associated with Amsoil).
I was disappointed with Mobile 1 Tri-Syn performance in the Four Ball test (even after a reduction in pressure and RPM's) since M-B's have overhead cams/rocker arms that really put an oil to the test to prevent wear and the 21 to 1 compression ratio puts a lot of stress on the pistons & rings to the cylinder walls. I especailly liked the dino oils good specs in the Four Ball test.
The NOACK test results were inline with the background info I found about the test since dino oil should evaporate more than synthetics. Unfortunately, I could not find any NOACK spec for Mobile's synthetic oils despite the fact that this test is required by the API before an oil can be rated for that particular classification. API requires that all oils have a NOACK rating of less than 15% evaporation before that oil can be rated in a particular API service category.
Based on the above info/specs, Amsoil synthetic diesel/marine 15W-40 is the best followed by Chevron Delo 400 15W-40. The next consideration is cost. The Amsoil costs $19.95 per gallon, plus S&H cost if ordered from the Corp web site, or pay the $10 preferred customer trial offer fee good for 6 mon. (or $20 for 12 mon.) to get a 15-20% discount (info from the web site). Chevron costs $5.28 per gallon at Wal Mart. Then, one would have to figure in the longer drain period for Amsoil of twice M-B's drain period resulting in oil changes at 6,000 miles (longer, like 20,000+ miles, if you use Amsoil's oil filters and air cleaners - which are not available for my 300D or any other M-B I know of - along with oil analysis to determine if you can go longer than 6,000 miles) versus draining Chevron at 3,000 miles (using oil/air filters made by suppliers to M-B) versus Amsoil's superior NOACK and Four Ball test specs, versus the fact that even the best dino oils begin to break down much sooner than synthetic oils do - meaning that Amsoil's superior NOACK and Four Ball test specs will last longer than the best dino oils, versus the very high cost to repair/rebuild a M-B engine (pardon my thinking out loud, or rather writing out loud).
Bo, any thoughts/suggestions/comments you have would be greatly appreciated.
America: Land of the Free!
1977 300D: 300,000+ miles
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Last edited by tcane; 04-19-2002 at 12:26 AM.