I doubt that it matters but I'm surprised
about the 'not for water cooled engines' part. The TCW-3 rating is by
the BIA (Boating Industry of America). I haven't seen an air cooled boat
motor in a very long time.
Actually I didn’t
intend to imply ‘not for water cooled engines’. I said ‘watercraft’ and
meant to say ‘personal watercraft (PWC). And, also, it seems I got
confused. The TCW3 rating is a NMMA rating (National Marine
Manufacturers Association). I had
read a long article I came across http://www.sea-doo.net/techarticles/oil/oil.htm,
and got mixed up on the NMMA TWC3 rating and the API-TC (American Petroleum
Institute) rating. (And if you read the article only once in its
entirety, you may be able to see why I got confused.)
For PWCs the author
is suggesting sticking with API-TC rating which is less common and more
expensive than oils that are TWC3 rated. And after re-reading, my conclusion
is that the TWC3 oils should be fine for a water cooled rotary. Some
highlights are given below.
What mix ratio are
you guys using?
Al
“Ashless
detergents are used in low temperature applications such as TCW3 oils where
the ring land temperature is held below 300 deg/f. These detergents work well
in engines where an excess of cooling capacity is available and power valves
are not used. Ashless detergents are manufactured form organic nitrogen
compounds (Hydrazine) instead of heavy metal compounds; therefore, they
produce no ash as they are burned away. This is where the name “Ashless” comes
from. Oils containing this type detergent have a characteristic Ammonia odor.
Ashless detergents were used in the first generation of Bombardier XPS engine
oil. The formulation was later changed to a low ash type detergent because of
the higher temperatures generated by the 787 engines.
Low Ash type detergent/dispersants are used in most
API-TC, Jasco FC and ISO GC certified 2-stroke oils. These oils are designed
for air-cooled high performance engines that operate under severe
load/temperature conditions. Low Ash detergents can keep the deposits to a
minimum at ring land temperatures as high as 400 deg/f. These detergents are
manufactured from compounds of Calcium and Magnesium (heavy metals). After
these compounds (Calcium Phenate or Magnesium Phenate) do their job, they burn
away, forming a heavy metal salt (ash) that is swept away during the normal
combustion process. Hence, this is where the name Ash-type detergent comes
from. Ash type detergents depend on the higher combustion temperatures (787
and 951 engines) to keep the resulting ash swept out. Therefore, the use of
these high performance oils in outboard or other mildly tuned 2-stroke engines
is not recommended.
Some manufacturers are using a combination of
detergent types (Ashless and Low Ash) to
provide a broader range of uses for their oil. It is important to note
that oil designed to meet TCW3 specs. only (Ashless) will not protect an
engine requiring API-TC (Low Ash) type oil. The converse is also true. Using
a Low Ash oil in an engine designed for an Ashless
type oil only could result in fouled plugs and gummy combustion
chambers.
I hear a lot of complaints about the high cost of some
2-stroke engine oils, mostly Bombardier XPS. Well, I have to agree, it isn’t
cheap, but neither are any of the other API-TC oils compared to the TCW3 type
oils. Unfortunately it just costs more to manufacture API-TC oils than TCW3
oils. Despite its relatively high cost, I cannot recall any Rotax engine
failing because of XPS oil. XPS oil was a joint development of Castrol
and Bombardier. Bombardier wanted a ‘universal’ high
performance engine oil that they could use in all their recreational products.
That meant oil would flow freely at –40 deg/f and still maintain sufficient
film strength at 350 deg/f. The first generation of XPS (1995) was formulated
using Ashless detergents; this allowed the Rave valves in the then new 787
motor to stick. The formula was later changed (1996) to a low ash detergent
that eliminated the rave valve sticking problems. There have been several
minor improvements in XPS since 1996. Castrol remains the only manufacturer of
XPS. This is a proprietary blend sold only by Bombardier. There are a number
of good API-TC type oils out there if you chose not to use XPS. If the oil you
want to use does not have the ATP-TC certification on the container, contact
the manufacturer. Most of them will be more than glad to provide you with
information on their products.
Do not use TCW3 in your SeaDoo PWC. I don’t care
if it’s a full synthetic or your brother-in-law uses it; for the reasons
stated above, it will not protect your motor when conditions get tough in your
motor.