Andy Hecker wrote:
You RX-8 drivers might enjoy this thread from an oil analysis forum. First
analysis I've seen for a Renesis.
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=001030
Cheers,
Andy
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Topic: Factory fill - Mazda RX-8 1.3L Renesis - 2037 miles on oil
molechaser
Junior Member
Member # 1823
posted November 20, 2003 08:45 PM
Been lurking around this wonderfully obsessed forum for a while now and
thought I would finally surface for air.
This is an analysis of the factory fill on my new Mazda RX-8. Some basic
background info on the Renesis engine. Its a 2-rotor, normally-aspirated,
Wankel engine. The construction is a sandwich with the rotor end housings
made of cast iron and the rotor housings made of chrome-plated aluminum.
The rotor side seals run on the end housings, and the apex seals run on the rotor
housings. The rotors themselves are cast iron.
Mazda recommends only 5W-20 SL, GL-3 oil for this engine in the US
(apparently 5W-30 elsewhere). The owner's manual hints that other
viscosities could be used depending on ambient temperature, but
the chart only shows 5W-20. The oil change interval is 7500 miles
for normal service, 5000 miles for severe service, and 3000 miles
for severe service in Puerto Rico (apparently has conditions
similar to he1l ). I will probably stay with roughly 3000 mile
intervals unless the analyses show otherwise, mainly because Houston
is closer to he1l than Puerto Rico.
A small amount of the engine oil is injected by a metering pump
into the rotor chambers to lubricate the rotor apex seals, so
make-up oil is routinely needed. I changed the oil at 2000 miles
because I was going to have to add a quart and did not want to
dilute the factory fill.
The engine has twin oil coolers and total fill is about 7 quarts,
but only 4 quarts drain on an oil change because the coolers are
located too low to drain.
Now for the numbers. Analysis by Blackstone sample numbers first,
then universal averages. No TBN was requested because
this was factory fill and a short change interval.
code:
Al 9, 4
Cr 5, 0
Fe 30, 9
Cu 19, 6
Pb 3, 2
Sn 2, 0
Mo 551, 42
Ni 0, 0
Mn 1, 0
Ag 0, 0
Ti 0, 0
K 9, 1
B 130, 38
Si 49, 10
Na 8, 3
Ca 1750, 1581
Mg 4, 194
P 745, 777
Zn 817, 988
Ba 1, 0
SUS viscosity @ 210F, 48.7, 52-61
Flashpoint F, 335, >355
Fuel%, 1.5, <1.0
Antifreeze%, 0.0, 0
Water%, 0.0, <0.1
Insolubles%, 0.2, <0.6
Blackstones comments: High wear and silicon are both common finds in new
engines such as yours. The wear is high due to
break-in of new parts, while silicon is from sealers and sand-casted
parts. The fuel is present because the rings have not
completely seated yet. Universal averages show typical wear
metals for an oil from this type engine after about 2500 miles use.
We suspect your engine will look that good or better in two or three
more oil changes. Check back for another look - all these
findings should improve in the next sample. Once past wear-in,
you'll be able to run the oil longer.
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Overall I am satisfied with the report and expect to see improvements as
time goes on. About 3 quarts drained out when I
changed the oil. I re-filled with 4 quarts of 5W-20 Pennzoil
and that just put it at the full mark on the dipstick (there are about 1.8
qt between full and low).
Comments from experts on the foum are appreciated and also any
insight as to what the factory fill was.
Cameron--
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