305/311 13 Oct 97  20:36:25
From:   Jim Dunmyer
Subj:   additives 3/6
Part 3


The Zinc Question

   The latest "miracle ingredient" in oil additives, attempting to usurp
PTFE's cure-all throne, is zinc dialkyldithiophosphate, which we will
refer to here after as simply "zinc."

   Purveyors of the new zinc-related products claim they can prove
absolute superiority over the PTFE-related products. Naturally, the PTFE
crowd claim exactly the same, in reverse.

   Zinc is contained as part of the standard additive package in
virtually every major brand of engine oil sold today, varying from a low
volume of 0.10 per cent in brands such as Valvoline All Climate and
Chevron l5W-50, to a high volume of 0.20 percent in brands such as
Valvoline Race and Pennzoil GT Performance.

   Organic zinc compounds are used as extreme pressure, anti-wear
additives, and are therefore found in larger amounts in oils specifically
blended for high-revving, turbocharged or racing applications. The zinc
in your oil comes into play only when there is actual metal-to-metal con
tact within your engine, which should never occur under normal operating
conditions. However, if you race your bike, or occasionally play tag with
the redline on the tach, the zinc is your last line of defense. Under
extreme conditions, the zinc compounds react with the metal to prevent
scuffing, particularly between cylinder bores and piston rings.

   However - and this is the important part to remember - available
research shows that more zinc does not give you more protection, it
merely prolongs the protection if the rate of metal-to-metal contact is
abnormally high or extended. So unless you plan on spending a couple of
hours dragging your knee at Laguna Seca, adding extra zinc compounds to
your oil is usually a waste. Also, keep in mind that high zinc content
can lead to deposit formation on your valves, and spark plug fouling.

   Among the products we found containing zinc dialkyldithiophosphate
were Mechanics Brand Engine Tune Up, K Mart Super Oil Treatment, and STP
Engine Treatment With XEP2. The only reason we can easily identify the
additives with the new zinc compounds is that they are required to carry
a Federally mandated warning label indicating they contain a hazardous
substance. The zinc phosphate they contain is a known eye irritant,
capable of inflicting severe harm if it comes in contact with your eyes.
If you insist on using one of these products, please wear protective
goggles and exercise extreme caution.

   As we mentioned, organic zinc compounds are already found in virtually
every major brand of oil, both automotive and motorcycle. However, in
recent years the oil companies voluntarily reduced the amount of zinc
content in most of their products after research indicated the zinc was
responsible for premature deterioration and damage to catalytic
converters. Obviously this situation would not affect 99 percent of all
the motorcycles on the road - however, it could have been a factor with
the newer BMW converter - equipped bikes.

   Since the reduction in zinc content was implemented solely for the
protection of catalytic converters, it is possible that some motorcycles
might benefit from a slight increase in zinc content in their oils. This
has been taken into account by at least one oil company, Spectro, which
offers 0.02 to 0.03 percent more zinc compounds in its motorcycle oils
than in its automotive oils.

   Since Spectro (Golden 4 brand, in this case) is a synthetic blend
lubricant designed for extended drain intervals, this increase seems to
be wholly justified. Also, available research indicates that Spectro has,
in this case, achieved a sensible balance for extended application
without increasing the zinc content to the point that it is likely to
cause spark plug fouling or present a threat to converter-equipped BMW
models.

   It would appear that someone at Spectro did their homework.


Increased Standard Additives (More Is Not Necessarily Better)

   Though some additives may not contain anything harmful to your engine,
and even some things that could be beneficial, most experts still
recommend that you avoid their use. The reason for this is that your oil,
as purchased from one of the major oil companies, already contains a very
extensive additive package.

   This package is made up of numerous, specific additive components,
blended to achieve a specific formula that will meet the requirements of
your engine. Usually, at least several of these additives will be
synergistic. That is, they react mutually, in groups of two or more, to
create an effect that none of them could attain individually. Changing or
adding to this formula can upset the balance and negate the protective
effect the formula was meant to achieve, even if you are only adding more
of something that was already included in the initial package.

   If it helps, try to think of your oil like a cake recipe. Just because
the original recipe calls for two eggs (which makes for a very moist and
tasty cake), do you think adding four more eggs is going to make the cake
better? Of course not. You're going to upset the carefully calculated
balance of ingredients and magnify the effect the eggs have on the recipe
to the point that it ruins the entire cake. Adding more of a specific
additive already contained in your oil is likely to produce similar
results.

   This information should also be taken into account when adding to the
oil already in your bike or when mixing oils for any reason, such as
synthetic with petroleum. In these cases, always make sure the oils you
are putting together have the same rating (SA, SE, SC, etc.). This tells
you their additive packages are basically the same, or at least
compatible, and are less likely to upset the balance or counteract each
other.


Detergents And Solvents

   Many of the older, better-known oil treatments on the market do not
make claims nearly so lavish as the new upstarts. Old standbys like
Bardahl, Rislone and Marvel Mystery Oil, instead offer things like
"quieter lifters," "reduced oil burning" and a
"cleaner engine."

   Most of these products are made up of solvents and detergents designed
to dissolve sludge and carbon deposits inside your engine so they can be
flushed or burned out. Wynn's Friction Proofing Oil, for example, is 83
percent kerosene. Other brands use naphthalene, xylene, acetone and
isopropanol. Usually, these ingredients will be found in a base of
standard mineral oil.

   In general, these products are designed to do just the opposite of
what the PTFE and zinc phosphate additives claim to do. Instead of
leaving behind a "coating" or a "plating" on your
engine surfaces, they
are designed to strip away such things.

   All of these products will strip sludge and deposits out and clean up
your engine, particularly if it is an older, abused one. The problem is,
unless you have some way of determining just how much is needed to remove
your deposits without going any further, such solvents also can strip
away the boundary lubrication layer provided by your oil. Overuse of
solvents is an easy trap to fall into, and one which can promote harmful
metal-to-metal contact within your engine.

   As a general rule of thumb these products had their place and were at
least moderately useful on older automobile and motorcycle engines of the
Fifties and Sixties, but are basically unneeded on the more efficient
engine designs of the past two decades.



     M.

--- Msged/386 TE 06 (pre)