[DeTomaso] Motor Oil Article

[michael at michaelshortt.com]

Don't know if anybody else finds this interesting, anyway here it is, ( I
still lake Castrol 20-50W)

Michael in Savannah


*Oil Basics*
Like any other facet of our hobby, engine oil is constantly changing as new
refinement techniques are developed. But as consumers we never realize how
often. And with recent advances in synthetic technology, many hobbyists feel
that conventional (or mineral) oil is an inferior product. But it, too, is
vastly superior to what was available just a few years back.

Whether synthetic, conventional, or a blend of the two, engine oils can be
broken down into two basic types--monograde and multigrade. Monograde oil
(also called single-grade) provides a stable viscosity--or its ability to
flow at a given temperature. And while monograde oil may have offered
slightly better operational consistency in the past, it can be too thick for
quick engine circulation during the initial start-up period in cold
conditions.

Multigrade oils were developed to offer maximum engine protection in nearly
any condition or climate. This concept entails incorporating specific
chemical additives to a single-grade oil to produce a hybrid with varying
viscosity that can react to temperature changes. The main benefit of
multigrade oil is improved circulation as a lesser viscosity oil when cold,
and improved protection as a heavier viscosity oil in normal conditions.

Advertised viscosity of a typical multigrade oil starts with the viscous
rating of the base oil at 0 degrees F, which is then followed by a W
(signifying "winter"), and the maximum viscous rating when warm. Simply
stated, 10W-30 would protect like single-grade, 10-weight oil when cold, and
single-grade, 30-weight oil in typical operating conditions.

Oil technology has produced a wide range of varying-viscosity, multigrade
oils that are extremely reliable. Recent revisions to cold-flow requirements
ensure that cold oil is thin enough to circulate quickly through a cold
engine for start-and-drive-type drivers. Protection, however, is only one
area of concern from auto manufacturers. Oil's effect on fuel
economy<http://www.highperformancepontiac.com/tech/hppp_0606_understanding_motor_oil/ratings.html#>is
the other.

It is formulated to reduce friction without compromising protection. Since
lower-viscous oils generate less oil-pump drag than higher-viscous oils,
lower-viscous oils typically utilize less power to circulate. The ideal
multigrade oil is one that circulates with the least amount of drag, yet is
heavy enough to sufficiently protect in normal conditions. This creates
slightly better engine efficiency, which can translate into a marginal fuel
economy increase. This compromise is why auto manufacturers commonly use
5W-20 and 5W-30 oil in today's engines.

The drawback to low-viscosity, multigrade oil is that it can offer less
high-temperature protection. This does not suggest, however, that
higher-viscous oils will offer any better protection in extreme conditions.
Any oil can become dangerously thin, offering little to no protection if oil
temperature grossly exceeds its intended operating range. But since
most passenger
cars<http://www.highperformancepontiac.com/tech/hppp_0606_understanding_motor_oil/ratings.html#>are
driven mild-to-moderately in all types of climates, 5W-20 to 10W-30
oils
typically suffice.

*Major Analysis Organizations*
There are two major organizations that rate oil quality for maximum consumer
and environmental protection. One is the American Petroleum Institute (API);
the other is the International Lubricant Standardiza-tion and Approval
Com-mittee (ILSAC). Either is recognized by--or assembled
of--representatives from the federal government, major auto manufacturers,
or major oil companies. These organizations set the oil-quality standards
and then issue approval ratings based on performance testing.

API ratings consist of a two-letter system that begins with either an "S" or
a "C." S-rated oils are approved for service-class engines, or
gasoline-powered engines used in cars and light-duty trucks. C-rated oils
are approved for the demands of commercial-class vehicles such as
heavy-duty, diesel engines. The letter following either is an oil approval
rating. Latest API ratings include SM and CI for the respective categories.

ILSAC approval is similar to that of API. Its rating system, however,
consists of a "GF" followed by a number. GF stands for "gasoline-fueled,"
and the number following is ILSAC's quality rating. The latest ILSAC
standard is GF-4.

As oil quality increases to meet new emission and performance standards, API
and ILSAC designate a sequentially higher letter or number to each new
category, which oftentimes supersedes its predecessor. We must realize,
though, that any current oil can be approved for a past category, but it
cannot be approved for the latest until it meets or exceeds that
expectation. The category rating of any oil is typically posted on the
container label.

*Recent Oil Formulation Changes*
Auto manufacturers have been required by federal law to warrant specific
components of the emissions control system on any '95-or-newer car or
light-duty truck for the balance of eight years or 80,000 miles--including
catalytic converters. In that time, it has been determined that phosphorus
in exhaust can negatively react with the converter's active catalysts,
rendering it inoperable. The cost of component replacement cannot only fall
upon the manufacturer, its failure can also create a vehicle that
excessively emits pollutants until said repair is made.

The largest amount of phosphorus inside an engine is in its oil. A compound
molecule named Zinc Dialkyl Dithiophosphate (ZDDP) is comprised mostly of
zinc and phosphorus, and has long been a common antiwear oil additive. ZDDP
offers key frictional-heat-activated qualities that form a sacrificial
chemical barrier on components that are under continuous high-pressure
contact. While much of the oil would literally be squeezed from between the
components in these conditions, ZDDP prevents the metal-on-metal contact
that could otherwise result. A classic example would be a camshaft lobe and
lifter.

Since phosphorus has been proven to negatively affect catalytic converters,
auto manufacturers and oil companies are working to find a suitable antiwear
additive to replace ZDDP. But that has been a major task. So, until it
happens, the analysis organizations have imposed a temporary limit on the
maximum amount of ZDDP in oil--no more than 0.01 percent by weight. It
appears this reduction has had a major effect on the hobby since its
enactment in January 2004.

*What This Means To Us*
>From its operational characteristics, the camshaft seems as though it
benefits most from ZDDP. But modern engines like the LT1, the LS1, and the
LS2 used in late-model Firebirds and GTOs have lifters with roller bearings,
which greatly reduce frictional contact on the lobe. Because of this, it
appears roller camshafts have been largely unaffected by the oil changes. It
is, however, an entirely different story with flat-tappet camshafts.

The recent spike in reported flat-tappet camshaft failure seems to be
consistent with the enacted ZDDP restriction. While some could argue that
lobe profile or a decline in camshaft hardening is to blame, that argument
may only be valid if several lobes of the suspect cam were affected. It
would, however, unlikely be the case if the problem is limited to a single
lobe. That then might indicate an issue with a specific lifter, its preload
setting, or insufficient lubrication.

Since proper camshaft break-in is such a critical step in ensuring its
longevity, most camshaft manufacturers are suggesting physical steps or
specific products for break-in. But some have recently begun advocating
certain products for long-term use, too. These include those oils approved
for commercial-fleet vehicles and/or separate oil additives that are
currently available from mail-order retailers, local parts stores, or GM
dealers.

Because commercial-rated and service-rated oils fall under different
standards, oils approved for commercial use typically contain more of the
desirable high-pressure, antiwear additives. Since many commercial-grade
oils have older S- or GF-category ratings, oil companies claim it is safe
for use in gasoline-fueled engines, unless catalyst failure is a concern.
Commercial-grade oil is also available in synthetic, conventional, or a
blend, and may fit a wide range of non-catalyst applications if it is
available in the desired monograde or multigrade viscosity.

Race-specific or specialty oils may be another alternative. We have found
that many of the lesser-viscosity offerings comply with the latest oil
standards. But many higher-viscosity oils are restricted to off-road-use
only. This might indicate different levels of ZDDP within each product,
which could have an effect on the exhaust catalyst. It would be worthwhile
to refer to the oil manufacturer's Web site for more detailed information on
specific products or category ratings.

We highly suggest that hobbyists familiarize themselves with the quality
standard and category rating information found on API's Web site. It not
only discusses current standards, it also shows how to decipher the API
"donut" printed on each oil container's label. We also suggest reviewing or
requesting the latest Material Safety Data Sheet (MSDS) from your preferred
oil's manufacturer. This information, which is oftentimes available on the
manufacturer's Web site, is an invaluable resource that specifies an oil's
API rating and chemical content.

*Conclusion*
If you own a new or late-model Pontiac, much of the presented information
may not apply. In that case, simply follow your owner's manual
recommendations. If you own a vintage Pontiac with a flat-tappet camshaft
and a cata-lytic converter, you may be forced to use latest-standard oil to
avoid the risk of catalyst failure. Engine protection, however, may be worth
the cost of periodic catalytic converter testing and any necessary
replacement. If you feel that it is, the following will apply.

Those of us who have older Pontiacs with flat-tappet camshafts might now
realize how much oil formulation has changed in recent years and its effects
on the hobby. The best suggestion we can offer is to follow your camshaft
manufacturer or engine builder's recommendations for break-in and long-term
use. Chances are it will include heavy-duty, commercial-grade oil, or a
specific bottle of oil-additive for the life of the engine. Following their
suggestions is wise not only for warranty issues, but it should also provide
many miles of enjoyment.


-- 
Michael L. Shortt
Savannah, Georgia
www.michaelshortt.com
michael at michaelshortt.com
912-232-9390


This email is protected by the Electronic Communications Privacy
Act, 18 U.S.C. Sec. 2510-2521, is confidential and may be legally
privileged. If you are not the intended recipient, you are hereby notified
that any retention, dissemination, distribution or copying of this
communication is strictly prohibited. Please reply to the sender that you
have received this message in error, then delete it. Thank you