Dumb ass mechanic

[krush]

Just a wild ass guess, but I rekn' most people on this site put so few hours on their detroits that it doesn't matter what oil they use.

[Briankinley2004]

The main reason I use Rotella 40W is so I dont have to keep up with what version of Delo I need to buy.

[rustybucket]

Here is a pretty good older thread. While Shell Rotella T1 meets spec with 1% sulfated ash, it is right on the borderline of the spec which calls for <1%. So really if you get picky about it T1 does NOT meet DD spec by .01%.

https://www.samsmarine.com/forums/sh...il-vs-chevron&

I have been using delo 100 but may check out the napa/valvoline offering next oil change as the delo 100 supply is getting low.

[racclarkson@gmail.com]

Just a wild ass guess, but I rekn' most people on this site put so few hours on their detroits that it doesn't matter what oil they use.

As to ash content and those consequences, I expect you’re right. But if you say the type of oil doesn’t matter, you are inadvertently opening up to someone who may then take the next step and go multi grade. That, as we all know, does matter. I cite a boat at my marina with 892TAs. It came in two years or so back with no apparent motor issues. The boat was run for a few months on the oil it came in on. Owner fished the jetty’s meaning more time at low rpms than offshore runs. I know first hand the owner then changed the oil in both using Rotella 15W40 and ran the boat over the following year for at least 50 hours. I spoke with his mechanic, admittedly not a DD specialist, who reports gauled main and camshaft bearings, so far. It apparently makes some noise on startup and began displaying a noticeable reduction in oil pressure. Owner doesn’t recall the oil pressure prior to reporting the problem, just that it was a little lower than the other motor and that it wasn’t always that way. I don’t know the cause. But it sounds like it could be too many dry starts. Possibly could be a worn oil pump that has trouble picking up thinner oil. As I say, the only thing I know for certain is the wrong oil was run. Samples sent.

[carolinacoast]

It's happened to me. If they will make it right, don't sweat it.

[rustybucket]

Just a wild ass guess, but I rekn' most people on this site put so few hours on their detroits that it doesn't matter what oil they use.

I mean, that's a pretty wild guess. I can't speak for others but we put 300+ hours on our old gal last year.

I would think oil spec would be MORE important for the low hour, low rpm users as well. The lower rpm's are going to lead to more ash buildup no matter what type of oil you use.

[oscarvan]

Regardless of how you use the engine, changing oil frequently (time and or hours) and putting the best match oil in there you can find is the cheapest insurance you can buy. This is not the place to skimp, ever.

[krush]

As to ash content and those consequences, I expect you’re right. But if you say the type of oil doesn’t matter, you are inadvertently opening up to someone who may then take the next step and go multi grade. That, as we all know, does matter. I cite a boat at my marina with 892TAs. It came in two years or so back with no apparent motor issues. The boat was run for a few months on the oil it came in on. Owner fished the jetty’s meaning more time at low rpms than offshore runs. I know first hand the owner then changed the oil in both using Rotella 15W40 and ran the boat over the following year for at least 50 hours. I spoke with his mechanic, admittedly not a DD specialist, who reports gauled main and camshaft bearings, so far. ................. As I say, the only thing I know for certain is the wrong oil was run. Samples sent.

Correlation does not equal causation. The multi grade "wrong" oil he was running is still vastly superior to the oil that was run in 2moke detroits back in 40's and 50's when they were designed. Main and cam bearings really are not "tough" on oil. My instinct leads me to believe there is another root cause. I've seen huge turbines, diesels, and other machines run on contaminated oil with only minor effects on bearing wear (usually grit or something). The "wrong" oil in a detroit is likely going to be plenty slippery. But, like all things in life, who really knows for sure LOL. I run synthetic in all my stuff. A guy on this forum has run synthetic in his 12v71n for 30 years.

[rustybucket]

Correlation does not equal causation. The multi grade "wrong" oil he was running is still vastly superior to the oil that was run in 2moke detroits back in 40's and 50's when they were designed. Main and cam bearings really are not "tough" on oil. My instinct leads me to believe there is another root cause. I've seen huge turbines, diesels, and other machines run on contaminated oil with only minor effects on bearing wear (usually grit or something). The "wrong" oil in a detroit is likely going to be plenty slippery. But, like all things in life, who really knows for sure LOL. I run synthetic in all my stuff. A guy on this forum has run synthetic in his 12v71n for 30 years.

I don't think it's the quality that kills the engines, it's the viscosity. There have been some pretty in-depth studies done on detroits in industrial or transportation engines when dealing with multi-grade oil. The results were pretty shocking and way worse damage from the multi-grade than I would have ever imagined.

[krush]

I don't think it's the quality that kills the engines, it's the viscosity. There have been some pretty in-depth studies done on detroits in industrial or transportation engines when dealing with multi-grade oil. The results were pretty shocking and way worse damage from the multi-grade than I would have ever imagined.

Please provide some of these studies, I'm curious to learn from them.

I did find this one. It was about EMD (2strokes) on ferries that were failing. They switch to multigrade piston engine airplane oil.

http://ctr.utexas.edu/wp-content/upl...s/0_5532_1.pdf

The research team found that the failures were
the result of three factors: 1) the poor ring pack design of these engines, which results in a high oil consumption rate, 2) the high ash content of the re-refined oil that was used in
the ferries, and 3) the decreased flame temperature for TxLED relative to 2D on-road diesel.

The research team recommends that Galveston Ferry Operations begin using Exxon Elite 20W50 in
all of its ferries. Although this is
an airplane piston engine oil,
aircraft oils are necessarily designed to minimize wear due to the danger resulti
ng from an engine failure at altitude. Thus, it was not surprising that this oil ha
d the lowest rate of change of wear metals of all oils tested.
Additionally, like all aviation piston engine oils, Exxon Elite has no ash whatsoever. Thus, it was
also not surprising that Exxon Elite also had the lowest rate of accumulation of calcium deposits.
Exxon Elite also had the second lowest oil consumption rate.