I was reading a thread on another forum. Someone was saying that using diesel oils to achieve higher ZDDP levels in a gas engine was a bad idea. It would be a shame if this is all true in regard to Rotella and Delo.
I googled a bit further, and basically the argument seems to be that that diesel oils contain too much of a form of ZDDP which activates at a higher temperature (primary ZDDP), which is less effective in a gas engine (with greater temperature range).
An additional argument is that all the unused detergents in diesel oils 'compete' for surface space on metal surfaces.
Any truth to either of these?
Below is an explanation from a website (which is selling something). Under that is the thread I mentioned. The first link also makes a claim about differences in sheer polymers.
http://www.cam-shield.com/acatalog/diesel.html
"Like ZDDP anti-wear chemistry, detergents are a surface active chemistry and compete directly for space on metal surfaces, such as the cam lobe and lifter face. So, in practice, the effective level of Zinc anti-wear is a bit lower than what we expect it to be based solely on chemical analysis. Additionally, the ZDDP that is generally used in diesel formulas is primary ZDDP (which activates at higher engine temperatures) since a diesel engine runs predominantly at operating temperature. In a gasoline engine, we must have both primary and secondary ZDDP (which activates at lower temperatures) since the engine will experience a significant number of cold starts. Also, the viscosity modifier polymers that are used in multi-viscosity engine oil to prevent viscosity loss at operating temperature (to protect the bearings) are different for diesel oil and gasoline oil. Diesels operate at essentially the same rpm all day long and need polymers that are shear stable to protect the bearings. Gasoline engines experience many large ranges of rpm during operation and require polymers that have both shear stability and thickening efficiency capability to protect the bearings."
http://www.corvetteforum.com/forums/c4-t...-corvettes.html
"Rejected Option 1: Using diesel (“C” series) oil in a gasoline engine for its higher zddp levels. This is an iffy proposition due to inherent differences in temperatures and operating conditions for these two very different types of engines. In publication SAE 860373 (sorry no link-- I bought this from the SAE and it's copyright protected), Figures 7a and 7b show that diesels are not as sensitive to detergent formulations, are well-protected with only primary zddp (i.e., the less effective kind), and do not need secondary zddp for adequate protection. All this is different in gasoline engines."
I googled a bit further, and basically the argument seems to be that that diesel oils contain too much of a form of ZDDP which activates at a higher temperature (primary ZDDP), which is less effective in a gas engine (with greater temperature range).
An additional argument is that all the unused detergents in diesel oils 'compete' for surface space on metal surfaces.
Any truth to either of these?
Below is an explanation from a website (which is selling something). Under that is the thread I mentioned. The first link also makes a claim about differences in sheer polymers.
http://www.cam-shield.com/acatalog/diesel.html
"Like ZDDP anti-wear chemistry, detergents are a surface active chemistry and compete directly for space on metal surfaces, such as the cam lobe and lifter face. So, in practice, the effective level of Zinc anti-wear is a bit lower than what we expect it to be based solely on chemical analysis. Additionally, the ZDDP that is generally used in diesel formulas is primary ZDDP (which activates at higher engine temperatures) since a diesel engine runs predominantly at operating temperature. In a gasoline engine, we must have both primary and secondary ZDDP (which activates at lower temperatures) since the engine will experience a significant number of cold starts. Also, the viscosity modifier polymers that are used in multi-viscosity engine oil to prevent viscosity loss at operating temperature (to protect the bearings) are different for diesel oil and gasoline oil. Diesels operate at essentially the same rpm all day long and need polymers that are shear stable to protect the bearings. Gasoline engines experience many large ranges of rpm during operation and require polymers that have both shear stability and thickening efficiency capability to protect the bearings."
http://www.corvetteforum.com/forums/c4-t...-corvettes.html
"Rejected Option 1: Using diesel (“C” series) oil in a gasoline engine for its higher zddp levels. This is an iffy proposition due to inherent differences in temperatures and operating conditions for these two very different types of engines. In publication SAE 860373 (sorry no link-- I bought this from the SAE and it's copyright protected), Figures 7a and 7b show that diesels are not as sensitive to detergent formulations, are well-protected with only primary zddp (i.e., the less effective kind), and do not need secondary zddp for adequate protection. All this is different in gasoline engines."
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