SHELL ROTELLA vs DELO 400

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I love FF talking oil.

Never ever had the slightest drop in cranking speed w 30Wt oil in my late model engine and it's spent most of it's time in Alaska. If you don't need it oil is better w/o viscosity improvers just like gasoline is better w/o octane booster ... if you don't need it. And I doubt if anyone on this forum needs it.

Richard I frequently put two quarts of 40wt oil in w the 30wt for oil changes in the summer. Same brand and type of course.
 
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This is very amusing to me. Any mechanic that would make that claim is smoking something beside diesel fumes. :rofl:

I can buy both brands in bulk here. Just take an empty bottle and pump your own. Back in the early 80's all you had here was Delo 400 straight weight. Almost all truckers and boaters used it. Now the shift is Rotella or Delvac.

When I go to those stores they all say the truckers switched to Mobil Delvac for the most part and Shell Rotella and all use multi weights. Not much Delo is being sold, especially straight weights.

I realize trucks have a shorter life cycle and newer one come in the picture.

My own personal experience was Shell worked much better for me than Chevron Delo. I think there wouldn't be any wear differences though as the mechanic stated. Frequency of oil changes with new filters, or replacing the filter more frequent and adding a quart should be more important than oil brand.

In my GMC diesel truck, I stopped using Delvac1, the synthetic, for two oil changes because I realized I changed to synthetic oil before the engine was broken in and seated. I was burning some. I went back to Delvac and each oil change the burning of oil has lessened and I am seeing it's breaking in slowly. I might need 50,000 miles on it before I change back. I made my first change at 16,000 miles. Way too early for a diesel engine.
 
JESSEDIVER49, FWIW: I would say that in the end most marine Diesels find their end of life comes for reasons unrelated to the brand of oil used. I would use either brand of oil and find other things to worry about.

Perhaps it is folk-lore, but I would be a bit cautious about changing brands each oil change, there was that talk about 'additive compatibility'. Not sure if it really is a big deal or not; in the end we carry two+ complete oil changes worth of oil, so even if we did want to switch it would not be every time..

But as to your original question: Availability, price, keeping it clean and in the engine are perhaps the most important things to worry about :blush:

-al-
 
Oil is Oil and API ratings are ratings IMO. Unless you own or have built something that is under massive amounts of stress (racing, extreme temps, etc.) or have something modern built to incredibly high tolerances with emissions components...old dirty diesels will like pretty much anything you give them as long as they meet or exceed the rating required by the manufacturer.


Sure synthetic is great but is the additive package and base stock really necessary on an older boat diesel...mmmmeh
 
Capthead,
The trucks get some benefit from multi-vis oil because they (their engines) are exposed to 100% of the cold in the air whereas our boats live in a relatively snug engine compartment and most even have some sort of heat. Mine does when it gets well below 30 degrees. No need for MV oil but the need for all the oil one can get into the fluid you pour into your crankcase is obvious. I'm with FF on this one ..... and several others as well.
 
Manyboats, I don't know enough about straight weight to say and both my oil business relatives have passed so I have some "digging" to do .
 
Pour out some 30w oil at 30 degrees and watch how slow it is. Or change your oil without warming up the engine. We know that trying to suck the oil out of a cold engine is really difficult. The only way oil will lube the engine is if it flows through all the bearing surfaces. Pour out some 0-xx synthetic at 30 degrees and then see for yourself the difference. If you want to reduce wear the solution is obvious. Personally I don't stress over it at all; my Lehman will outlive me on a diet of Delvac, Rotella, Delo 10-30.
 
Oil is not compressible (as far as I know) and oil pumps in engines are positive displacement gear pumps so at any given engine speed the amount of oil pumped through an engine is the same w any viscosity oil used.

Tell me if I'm wrong about the above and I'll change my tune.

I put 30wt oil in my old Nissan and it started right up at 25 degrees F (or perhaps colder). I realize that if one tried to start a cold engine at 40 below the shaft to the oil pump gears may be at risk of breaking. However most all of our boats engines don't get colder than about 40 degrees so I see no need for multi-viscosity oil. We also warm up our boat engines slowly.

The only real reason I see for using MV oil in our boats is so the operator can feel like he's not an old codger that is so unconnected he dosn't know about the newest and most advanced products and their advantages. But some advantages of newer products will not be realized in all circumstances. One of those circumstances is in small boat engines that don't get cold and aren't needed to run at heavy loads immediately after being started.

This is however very achedimic as engines will run almost exactly as well and as long w MV or single weight oil as long as the oil used conforms to the engine manufacturers recommendations.
 
I'll bet there are maybe, oh, three owners on this site who will ever get anywhere near the end of life of any of our boat engines. Gasoline, probably. But these big slow-turning diesel engines die or break or fail for many other reasons than oil. Most of our engines fail for lack of use, perhaps lack of maintenance, but never for high-time worn out reasons. I have heard that Lehmans running a pump or a genset can get 30,000 hours, but they are only shut down for oil changes (unless they can be hot-oiled?). Lots of engines are life-rated for so many thousands of gallons of fuel. I'll bet that only 2 or three of us will ever reach that.

Therefore put any oil you want in there, your engine will never know the difference and you will never live long enough to see your engine die of old age.
 
Is every bearing surface on an engine forced lubed across its entire surface?

I have always been taught, no.

That is one of the the reasons for lower viscosity oils, otherwise just use 90wt everytning.
 
Pour out some 0-xx synthetic at 30 degrees and then see for yourself the difference. If you want to reduce wear the solution is obvious

You will see the difference , but your geared oil pump wont.

Most bearings require oil pressure as they ride on the pump action caused by the space between say rods and crank.

The tappets rely in film strength , as does the piston after the rings have scraped 99+% of the oil away.

>but they are only shut down for oil changes (unless they can be hot-oiled?)<

Long life Prime gen sets may have 2 oil tanks , each pre heated by a line from the engine that are simply switched as the oil change is done.
 
Scott wrote;
"Is every bearing surface on an engine forced lubed across its entire surface?
I have always been taught, no."

I have not been taught anything in that regard but common sense would indicate that;

First the question isn't about "forced lube" but "is there oil on the bearing surfaces that will keep the metal bearing surfaces from touching each other"? Notice I didn't say "enough oil" or anything about pressure. It's about keeping the metal surfaces apart. And if they were not kept apart serious damage would result.

Secondly looking at an oil pressure gauge while starting an engine indicates there is no oil pressure at the oil pressure sending unit or sensor for several revolutions. Nobody can be sure of how much damage (if any) is done during these few revolutions but millions of engines all over the world have this experience daily. And if it were an actual problem engines would be equipped w pre-lubers.

What was the oil system on the Chevy's in the 30's and forties? As I recall it was refereed to as a "splash" system. And I think this system relied on the crankshaft splashing oil around in the crankcase. I think they had an oil pump and pressure fed bearings on the crankshaft and elsewhere but relied on splash oil for cylinder wall lubrication. But not sure. Does anybody remember how those old Chevy's got lubed?
 
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FF of course, dry-sumped. Easy-peasy.

I stand by my position - just read the label, choose the correct standard and just put oil in it.

Cooler failure
Manufacturing defect
Ingesting salt water
Coolant failure/overheating
Owner doing something stupid/operator error
Maintenance neglect (change that oil occasionally)
Correct oil level

Type of oil? No

Best way to get long life out of your engine? Use it lots.
 
I have seen the test data where bearing surface film strength and retained oil is measured over time. This data reveals how long an oil film will hold up with an engine shut down thus allowing startup safety before oil pressure build up. Under identical shutdown test conditions some oils are retained on bearings for weeks and others days.

Don't ask me for details as this was some time ago, but is indeed how Cat and others come to specify acceptable oil brands and offer and stand behind new engine warranties. I'd presume this is why one does not buy an el cheapo oil and goes for the "better" stuff. I saw a gallon of DELO 400 yesterday at WalMart for $13. Pretty cheap insurance.
 
Very interesting Tom.
I kinda like it when my cars don't start immediately .. acts like a preluber. I have an old Nissan Stanza that starts instantly and wonder if that's desirable. Not much wear on the starter motor though. That would be nice for an Alaska bound boat and most of us have a way of doing it. I can crank my engine over at idle for 5 to 10 seconds w/o the glow plugs on. Then turn on the glow plugs for 8 to 10 seconds and start instantly w a pre-lubed engine.

Wonder what in the oil would cause it to cling to metal for longer periods. Like VI improvers it would be something in the oil that would not be oil and thus may reduce the lubricity of the oil some small amount. But perhaps it's not like an additive and the "characteristic" is found in the "base stock"?

It's been shown that buying a brand name product from other than a trustworthy and time honerd source can result in buying an inferior product. Sorta like "seconds". I have for most all my life thought a top brand product was just that whoever you bought it from but no more. Case in point .... "Outlet stores". They sell merchandise that will not be shipped to "mother stores". I don't go into WallMart stores for other reasons but I think it depends on many variables so often or much of the time the product is exactly the same whatever store it's sold in. Don't really know but I do think a product is more likely to be as the brand suggests at it's prime outlet source. Like Shell oil at a Shell gas station. We live in a much more complicated age now as consumers.
 
manyboats said:
Oil is not compressible (as far as I know) and oil pumps in engines are positive displacement gear pumps so at any given engine speed the amount of oil pumped through an engine is the same w any viscosity oil used.

Tell me if I'm wrong about the above and I'll change my tune.

Respectfully, you are wrong. The same amount of oil goes through the pump but in all the engine bearing gaps less oil goes through when the oil is cold and more goes through when the oil is hot. When less oil is flowing more is diverted through the engines oil pressure relief system. When more is flowing less is by-passed. Viscosity is important to change the way oil flows at different temperatures, You should use the oil viscosity the engine manufacturer calls for because he has done the testing and has a basis for whatever he calls for.
Click to expand...
 
manyboats said:
What was the oil system on the Chevy's in the 30's and forties? As I recall it was refereed to as a "splash" system. And I think this system relied on the crankshaft splashing oil around in the crankcase. I think they had an oil pump and pressure fed bearings on the crankshaft and elsewhere but relied on splash oil for cylinder wall lubrication. But not sure. Does anybody remember how those old Chevy's got lubed?
Click to expand...

Chevy 216 and 235 cu in engines had circular channels under each rod in the oil pan. Each rod had a scoop. As the crank turned the scoop on the bottom of the rod traveled along the channel and scooped up the oil. This created a pressure and oil was then pressed up through the engine oil galleries. Every time the rod came around into the oil it scooped a little more oil.
 
obthomas,
So there is/was no convential oil pump. I kinda thought so but decided surely there must be. So most of the engine probably starts w/o oil pressure or oil flow to it's bearings. In their day they were considered a long lasting engine so it adds to the idea that residual oil in engine bearings provides adequate luberication.

Re post # 46 how can less oil flow through the bearing when the engine is cold when the source of oil remains the same .. the pump. I would suggest that the same amount of oil flows through the bearings but at a different velocity. Just like when a river widens the current slows but the volume remains the same. But the amount of oil in a worn bearing would be greater offering several advantages including more "cushion". More oil in there to "squish" out.

So the volume of oil passing through the engine is the same irregardless of the viscosity rating.
 
It's a good thing the excavating contractors I worked for didn't worry as much about oil and their engines as boaters, if they did we wouldn't of moved much dirt?.
 
manyboats said:
obthomas,
So there is/was no convential oil pump. I kinda thought so but decided surely there must be. So most of the engine probably starts w/o oil pressure or oil flow to it's bearings. In their day they were considered a long lasting engine so it adds to the idea that residual oil in engine bearings provides adequate luberication.

Re post # 46 how can less oil flow through the bearing when the engine is cold when the source of oil remains the same .. the pump. I would suggest that the same amount of oil flows through the bearings but at a different velocity. Just like when a river widens the current slows but the volume remains the same. But the amount of oil in a worn bearing would be greater offering several advantages including more "cushion". More oil in there to "squish" out.

So the volume of oil passing through the engine is the same irregardless of the viscosity rating.
Click to expand...

Not so. Engine oil pumps have pressure regulating valve that open if pressure goes above a certain level. Cold engine the valve is usually open and a good bit of oil is diverted back to sump. Flow at the bearings is then very slow due to the viscosity. But the bearings are happy, you don't need pressure, just need the presence of oil. Pressure assures presence!!

On a cold start, the bearings usually still have a hint of oil present, enought that metal to metal contact ends after say a quarter turn of crank. Engine might make some noise til pressure comes up and floods bearing, but that does not mean bearing is being damaged.

That's why most engine guys don't bother with prelube pumps.
 
Also thin oil film bearings on rods and cranks are coated with babbit. A tin like materal. This babbit protects the metals when they do touch for that instant on start up. The babbit doesn't go any where it just smooths out for the next time the engine is started.;
 
Yes, you do need pressure. If there is no pressure, the oil is quickly removed from the bearing surface, the metals of the "bearing" touch and you sustain damage. You can mitigate this effect if you have very smooth surfaces and you have an oil film present. This oil film will dissipate very rapidly, but on startup, the oil pump provides pressure to the bearings (perhaps not yet the gauge) and you have minimal damage. Also, there are much lighter loads except rotational loads on the main bearings until the engine fires, which is when the oil is essential. The noise you hear on startup is the valve train, which is not loaded the way that the "big ends" are, do not need the oil film immediately and will quieten as soon as the oil circulates.

Having said all that, the engines are spec'd to last so many hours before rebuild. If you never shut them off, or if when you did, you pre-lubed them like a large ship's engine would be, they will go longer. Cummins says a particular engine will last "100,000 gallons of fuel," I don't remember the actual amount for my engine, but that is contingent upon its duty cycle, in my case M1 or continuous.

They know that if their engines are used as per the duty cycle, started "dry" and from cold, they will go that long. Then they are worn out and need a rebuild.

If the oil pressure fails and the oil film in the bearing dissipates, you will have instant damage from which the bearing will never recover. The engine may run for some time after this occurs but you have significantly shortened the life of the engine. It is oil pressure that prevents this, not the type of oil.
 
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oK good,
Forgot about the pressure relief valve and some other stuff. Good learning thread. Something else I remember from the past is that pounding main bearings and hammering rod bearings would last some time if rpm was not excessive. I wonder if metal to metal contact was being made w the knocking. I doubt it but what would make the knock?

At any rate I believe bearings will be happy as long as the oil is there in sufficient quantity and of high enough viscosity to keep metal from metal.

I just bought a 2nd Suburban that has a "crate" engine and think it is spect'd for 5W-30 oil. That's what the PO said and I don't know if the automatic transmission is original. I could use a reduction in friction there.

River Cruiser,
I for one am not worried about any of this stuff. And will continue using straight 30 wt dino oil in my Mitsubishi until somebody shows me a need for something else.
 
Positive displacement gear pumps are only really "positive displacement" when new. As soon as thing start to wear, oil will be bypassed internally between the gears in the pump. The only truly "positive displacement" pumps are diaphragm pumps where there is no chance of leakage from the pressure side to the suction side.


Bob
 
BobH said:
Positive displacement gear pumps are only really "positive displacement" when new. As soon as thing start to wear, oil will be bypassed internally between the gears in the pump. The only truly "positive displacement" pumps are diaphragm pumps where there is no chance of leakage from the pressure side to the suction side.


Bob
Click to expand...

The intake side is beginning neglected too. Flow into the pump will have an impact on outflow. Think of trying to pump grease vs oil out of a bucket with the same pump and intake screen as in our engines. Worst case the grease doesn't flow at all.
 
mike66 said:
The intake side is beginning neglected too. Flow into the pump will have an impact on outflow. Think of trying to pump grease vs oil out of a bucket with the same pump and intake screen as in our engines. Worst case the grease doesn't flow at all.
Click to expand...

This and the previous post were proven by me back when I was young and (more) naive. I thought if 20w-50 was good in the summer (In NH) it should be fine in the winter. On really cold days (10-15 deg) it could take 30 seconds of running for the oil pressure to rise from zero! After a couple of winters of this, the bearings were shot. So no, the oil pumps are not really positive displacement and flow at cold means a lot. Sure we don't have this extreme in our boats, but its an extreme example of what happens at startup with cold flow.

Ken
 
You should use the oil weight that the engine manufacturer recommends for the temperature where you operate.
 
obthomas said:
You should use the oil weight that the engine manufacturer recommends for the temperature where you operate.
Click to expand...

Absolutely. Unless the specs were written 30 years ago and something newer has come along that may surpass those specs. Oil is probably at the bottom of the list of reasons for engine death, except for lack or loss of it. Under extremes of temperatures and service it becomes more important.
 
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kchace,
You don't mention what kind of vehicle this engine was in. And those temps aren't really that cold for road vehicles. Never heard of anything like that happening before. In college I drove a 1950 Plymouth to work 10 miles away often slightly below zero degrees F. Was hard to start as it cranked so slow but it always eventually started and got me to work. My 12 volt Mercury would not. But in our boats most of us keep our engine compartments well above freezing as the seawater has no anti-freeze in it and is vulnerable to freezing. Do you think there could be another reason for your bearing failure?

obthomas,
Yes but changing the viscosity on an older engine could have a downside as the engine was designed for what was originally specified. 1960 30W Chevron diesel lube oil is much improved in the new modern 30 W product. Most likely the only feature not incorporated in today's 30 W oil is the MV capability. And that's not exactly a new feature of oil. IMO we don't need MV oil in our boats.
 
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My engines are 30 years old and the stickers on the engines call for API CD 20W30 oil.

Now the CD specification is long gone but the 20W30 is still the same as it was 30 years ago. When you look up the CD specification and see that it is obsolete you have to surmise its replacement and when you do you will find that the CD is most equivalent to a current API service rating of CI-4. The 20W30 viscosity rating is still available in this oil today. Since I change oil at 100 hours or each season I have found no reason to go to synthetic or synthetic blend. I remain convinced these thirty year old engines will last longer than me. I use and will continue to use CI-4 20W30 oil.
 
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