Considerable amounts of sulfuric acid are produced in marine diesel engines during the combustion of high-level sulfur fuels, thus causing corrosive wear. The acid-neutralizing ability of marine cylinder lubricants (MCLs) is therefore a "measuring stick" of their quality. A new experimental protocol was previously published to qualitatively test the acid-neutralizing ability of marine cylinder lubricants. Using a capillary video-microscopy technique and measuring the shrinking rate of the size of nitric-acid drops in MCL, the acid-neutralizing ability of commercial MCLs, as well as model lubricants, can be determined quantitatively. The shrinking rate of the nitric-acid drop size in MCL was constant during the reaction period and independent of the initial drop size. Analysis of the experimental results, following an interfacial neutralization reaction mechanism, suggests that the adsorption of overbased reverse micelles on acid-oil interface is the controlling step in the reaction process. The presence of small amounts of dispersant (1 wt. %) in a model MCL on the neutralization reaction decreased the reaction rate for both nitric and sulfuric acid, while further increase in dispersant concentration (up to about 4%) did not reduce the acid-neutralizing ability further. For sulfuric acid, dispersants act also to effectively disperse the hydrated calcium sulfate crystals produced by the neutralization reaction with sulfuric acid.