Oldfeller--FSO wrote on 08/01/12 at 06:58:04: Bill, you misquote him. He said
if you call Shell they won't recommend it.
He got called on that one by the way, so let's see what he comes up with.
Justin,
A "spark plug diesel" can be a lower compression diesel engine, these are sometimes of the two stroke variety. They can get twice as many power strokes per minute that way, but the intake charge is contaminated with some exhaust gases from the last power stroke. They also have to dump off twice the amount of combustion heat input compared to a 4 stroke diesel.
These engines are mostly marine diesel engines and they burn very crude low grade thick type oils. But they are very cheap to run and they have a whole ocean full of cooling water to keep them from melting down.
A compression fired diesel is a
very high compression 4 stroke engine, so much so the air gets literally red hot due to compression heating. At this very high compression level, the injectors then shoot in the fuel mist that instantly ignites and burns.
Sounds fairly hairy, doesn't it? Folks here
http://forums.tdiclub.com/showthread.php?t=270799 say it reaches 614 degrees Celsius due to compression heating in a relatively low compression 16:1 VW four stroke glow plug type diesel engine. The real open road big diesel rigs commonly run 20:1 compression ratios --- and wait, there's more.
Let's take that same engine and supercharge it to 20 something psi of intake pressure then compress that pre-compressed air charge 20:1 and see what you get.
Why do that? MORE POWER AND TORQUE from the same displacement engine of course .....
Rotella oils live very long lives in completely hellish conditions in their diesel world. The oil is built to take this hell for 10,000 miles at a shot (and this is a minimum sort of mileage number, btw).
Our little low compression low operating temperature motorcycle engines are nothing to this oil, a walk in the park. Plus, we change the oil every few thousand miles which is a total joke to the additive packages the Rotella oils carry.
Detroit Diesels are common in tugboats, & 18 wheelers, & on frac pumps,
Ive never seen a spark plug diesel, I guess theyre out there,,IDK, but the article said the oil hadnt been tested in a spark fire engine, so, only diesel applications were recommended,, Thats why I asked the difference in oiling needs for spark plug fired engines( I thot they meant gasoline) ..
IDK how much different the heat issue is for a 2 stroke vs a 4.. but as you point out, it fires at TDC, every time,, so, yea,, twice as much fire to handle.,.so, if the oil is okay in a 2 stroke diesel,, Id think it would handle a 4 stroke gas,, the article said it hasnt been tested,, not that it wouyldnt work,