Larry W4CSC wrote:

I'm unfamiliar with Australian oil ratings as I'm on the other side of the
planet. Here, what concerns me is our oil (both dino and home made) has
been quietly devalued because it cannot pass the new SAE tests for 2-stroke
and 4-stroke diesels, once these were separated tests. So, you look on the
fancy can with the checkered flags and pictures of NASCAR race drivers and
in the SAE rating circle it says SJ or SK or whatever S rating the gas
engine manufacturers are using now....but NOT D-2 or D-4 for diesel use.
What have they left out? Diesel oils all have detergent in them because of
all the nasty carbon blowby that turns them black. Have they quietly
stopped adding detergent to keep the engines (gas and diesels) clean? Who
made that stupid decision....car manufacturers trying to wear out the cars?

I'm not fascinated with home made oils. I used Mobil 1 synthetic oil in my
Honda EU3000i electronic power plant a couple of times when it was new.
Synthetic oil was rated for air-cooled engines, not water cooled cars. It
was EXPENSIVE. I didn't care, it doesn't use much. When I sucked the
synthetic oil out and looked at it after 100 hours, I was scared I'd ruined
the Honda. It looked like it was BURNED!...it was BROWN! That ended that.
I started using the same Rotella-T (Shell) or Chevron's Velo 400 4-stroke-
rated DIESEL oils that American Truckers driving like hell down the
interstate with amazingly heavy loads on their engines run for millions of
miles between overhauls. What professional trucking companies use to
maximize their engine life speaks VOLUMES more as to what is the right oil
to use in any engine.....than the marketing department's motive of any oil
company trying to squeeze $5/quart out of some home made oil in the
checkered flag can. The genset seems ok at a thousand hours and Velo or
Rotella DON'T come out BROWN!...(c;


Larry,

Thats an interesting insight. I grew up on a farm where we ran diesel
tractors, and we used to buy diesel rated oil from the local CooP (pronounced
Co-OP for you city slickers by the 50 gal drum. Later, I owned a Cummins
powered diesel truck, and always used Rotella because thats what the owners
manual recommended.

I've always run regular 10W-30 motor oil in my gas powered vehicles, and have
generally had good luck with it, but I'll bet that you are right about the
diesel rated oils being higher quality and having better detergents. Diesels
generally run compressions of 24:1 where the average auto today is more like
8:1. There is a lot more pressure on the rod and main bearings in a diesel
because of the higher compression.

I'll bet that there are some mechanical engineers lurking about who could
probably explain all about the SAE oil ratings in great detail.

Don W.