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Oil Additives Bad For Aluminum Blocks?

A team of chemists and mathematicians at the University of Western Ontario deduced that most oil additives are complicated compounds containing zinc and phosphate. They then used computer simulations to find out what happens "at a molecular level when a film of oil containing additives is compressed between two hot, hard surfaces" like engine parts. They concluded that as the pressure rises, the molecules of zinc and phosphate form cross-links with each other, according to a science report in The Washington Post. In engines of steel alloys, this process helps minimize wear. But not so in aluminum engines, where the cross-linked molecular hash becomes harder than the metal and abrades the aluminum surfaces. In other words, if these guys are right, additives are good for engines with steel parts but potentially harmful if used in engines with major aluminum parts, especially on wear surfaces. Experts at the American Petroleum Institute told TheCarConnection they were not familiar with the Ontario study. -Mike Davis
 

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Most "normal" oils have Zinc and Phosphates in them. Zinc is an ANTI-WEAR additive. Phosphate is a detergent additive.

Bearings have been made out of lead, aluminum and other soft metals. They support harden/forged (Cranks and Cams), guess what? No sudden bearing failures in aluminum block motors.

Rover/MG/TVR has been using Aluminum blocks since the 60s. If there was a problem you would have heard about it LONG before now.

Most motors have aluminum heads even if they have Iron blocks. The cast or forged cams ride in the aluminum head WITH NO BEARINGS. The only lubrication is OIL. They survive fine for well over 200,000 miles.

Assuming what this "report" claims were true, it would only serve to HARDEN the soft metals, and thus REDUCE wear, not increase it!

Junk science at it's finest.
 
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Oil Additives Bad For Aluminum Blocks?

A team of chemists and mathematicians at the University of Western Ontario deduced that most oil additives are complicated compounds containing zinc and phosphate. They then used computer simulations to find out what happens "at a molecular level when a film of oil containing additives is compressed between two hot, hard surfaces" like engine parts. They concluded that as the pressure rises, the molecules of zinc and phosphate form cross-links with each other, according to a science report in The Washington Post. In engines of steel alloys, this process helps minimize wear. But not so in aluminum engines, where the cross-linked molecular hash becomes harder than the metal and abrades the aluminum surfaces. In other words, if these guys are right, additives are good for engines with steel parts but potentially harmful if used in engines with major aluminum parts, especially on wear surfaces. Experts at the American Petroleum Institute told TheCarConnection they were not familiar with the Ontario study. -Mike Davis
Justice Brothers Oil Metal Conditioner.
 

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This is good information and one of reasons on Porsche ANY additives are strictly verboden.
 

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It is not an ordinary aluminum casting material that is used on unsleeved cylinder bores:


The fact that many manufacturers have gotten the aluminum casting materials and process correct, whereas Chevrolet with the Vega did not, suggests to me that there are different formulas out there, and maybe different casting processes. I would also suppose that the tolerances of the pistons against the bores, along with the piston ring materials used, are a factor.

It's therefore can't be a single analysis of additives that works for all manufacturers, and one should carefully follow the manufacturer's mandates. You have to assume here that Porsche may well have tested many additives, and they know more about their particular engines than a macro-analysis done at a university.
 

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It is not an ordinary aluminum casting material that is used on unsleeved cylinder bores:


The fact that many manufacturers have gotten the aluminum casting materials and process correct, whereas Chevrolet with the Vega did not, suggests to me that there are different formulas out there, and maybe different casting processes. I would also suppose that the tolerances of the pistons against the bores, along with the piston ring materials used, are a factor.

It's therefore can't be a single analysis of additives that works for all manufacturers, and one should carefully follow the manufacturer's mandates. You have to assume here that Porsche may well have tested many additives, and they know more about their particular engines than a macro-analysis done at a university.
I'm aware of at least two machine shops in Ohio that survived during the late 1970's and early 80's doing re-sleeve's on Vega's. But at least, Chevrolet figured out how to ship them cheaper with this:

486805
 

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aluminum alloy engines have been in wide spread use since the late 1980's Aluminum heads even longer than that... Aluminum is much easier on engine oil than cast iron is...unless the additive packages states not for use in X type of engines, then it is fine.
 

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I am thinking the key phrase in the quoted study may be "...They concluded that as the pressure rises, the molecules of zinc and phosphate form cross-links with each other... "

However, in a properly designed mechanical device, the surface-area of the bearings is such that any 'pressure' is distributed to reduce peak loading. There are always inescapable exceptions (gear-teeth, cam lobes...etc) but these are always of hardend steel.

Some automakers, in an effort to cut costs, have reduced the pressure-points too much with famous results. (too high peak-load on too small an area)

** VW had Cams which wear out in 50K miles if you do not use 'special' oil which contained the proper additives..... the big problem was that 'special' oil WAS NOT AVAILABLE in North America unless you went to dealership

**GM had some engines which the camshafts would 'round out' (no more lobes).


Infact, it has LONG been known that using GL5 gear oil with sulfer-based EP (Extreme Pressure) additive can lead to wear on bronze bushings. (Not unlike the quoted 'study') However, it has also been proven that properly-designed bronze-bushings do not have the loading which induces the hardening effect mentioned in the 'study'.

Bottom line - This 'study' concludes nothing new which has not been understood for many long years.
 
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