aluminum engines & oil additives

[hha27d]

Oil Additives Bad For Aluminum Blocks?
from carconnection.com 3/17 (daily edition)

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

 

[MolaKule]

Yes, this topic has posted in about three different threads on here.

1. This was reported in the Washington Post by a non-tribology/chemistry person (reporter), not exactly a newspaper noted for accuracy and unbiased reporting.

2. Aluminum bearings are made of different aluminum alloys than aluminum engine blocks.

3. The study was a THEORETICAL study using simulation, not an actual laboratory study.

Don't make too much of it, IMHO.

 

[T-Keith]

Was there ever a physical study done to back up or disprove it? It seems like it would be pretty important if it were true since most engines have aluminum parts even if the block and heads are cast iron.

Is this ZDDP we're talking about?

 

[fuel tanker man]

It is ZDDP they're talking about...

I think if it were as bad as all that, we'd have been seeing some disproportionatly high Aluminum numbers in UOA's for particular engines, and we just don't. Harley Davidson engines have quite a bit of Aluminum in them, and they thrive on high ZDDP levels--and have for years. Some such engines have gone over 400,000 miles without a major overhaul.

I would assume that the big oil companies have paid thinkers, rather than college kids, formulate their oils.

Aside from all that, everytime I hear about a "computer simulation" I get real skeptical. Garbage in, garbage out. And all it takes is one little oversight in the program or the input data and the whole cake falls.

Dan

 

[Rickey]

Wouldn't this theory if correct result in very bad engine bearing wear problems? I am assuming here that bearing material is even softer than aluminum.

Rickey.

 

[JohnBrowning]

Lexus V8 enignes use aluminum based bearings and so do the Toyota V8's. I am going to guess that most of the recent I4 adn V6 motors designed by Toyota are following suit. Even ALuminum beraings are not 100% aluminum they contain one or more of the following as wellL: Tin,Lead,Cadnium,Copper etc.... I think we would be seeing a huge spike in ALuminum on newer Toyota's and Lexus engines if this was the case. We do not see any more aluminum in these engines UOA then any other engine with aluminum in their make up!

 

[Huhwhye]

Don't most engines have aluminum pistons, and don't most engines that have aluminum blocks have a steel wear surface. So according to this study we would see a lot of wear between the piston and cylinder wall right?

I don't believe that at all.

 

[kreigle]

quote:

---

Originally posted by Huhwhye:
Don't most engines have aluminum pistons, and don't most engines that have aluminum blocks have a steel wear surface. So according to this study we would see a lot of wear between the piston and cylinder wall right?

I don't believe that at all.

---

I don't have steel liners in my engine.

http://www.saffil.com/metal.htm
http://www.saffil.com/pdfs/automotive/data/mmcprop.pdf

quote:

---

In 1990,Honda launched a new generation of aluminum engine blocks with fibre reinforced cylinder walls replacing traditional cast iron liners.The first model selected for production was the Prelude Si,a 16 valve in-line 4-cylinder engine,using a new casting process to incorporate the Saffil -carbon fibre hybrid preforms.
Elimination of he cast iron liner using MMC technology allows a reduction in material thickness between the adjacent bores.Tightening the cylinder spacing in this way results in reduction in he overall length of the engine and a weight saving on the block of around 4.5kg.
Honda has since expanded the use of MMC engine
blocks and include models of he Accord,Ascot
Innova and the S2000.

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The 1990 and 1991 Preludes that got the very first generation of these engine blocks are well known on Honda forums for being oil burners.

I just mailed out an oil sample to Butler. I guess I should look for high Al in the results.