Outboard Oil -

[Cosmic C]

Here are my 2 cents:

1. Delo 400 is primarily a diesel engine oil for commercial fleets. It is formulated to also meet most gasoline engine specs so that it can be used in mixed fleets.

2. Delo 400 does not come as a 10W-40; it comes as 10W-30, 15W-40, and 10W, 20, 30, 40, and 50 single grades.

3. A 10W-30 does indeed act like a 10W oil at low temperatures and a 30 weight oil at high temperatures. It has what is called a high viscosity index (VI), which means it doesn't thin out as rapidly as a single weight oil as it gets hot.

4. Most multigrade oils achieve the high VI by the addition of viscosity index improvers. These are polymeric compounds that thicken the oil more at high temperature than at low temperatures and thus impart the multigrade characteristics.

5. These polymeric compounds lose their effectiveness (and even break down) at high shear rates. So, while 3. above is true at low shear rates, i.e. in the sump, in the high shear parts of the engine (bearings, cams, piston walls, etc.) a 10W-30 oil does NOT act like a 30 weight oil, but more like a 10 or 15W oil.

6. One of the many reasons that synthetics are better is that they are inherently much higher VI fluids than mineral oils, and so don't need anywhere near as much VI improver to achieve multigrade characteristics (most synthetic 10W-30 oils, for example, don't contain any VI improver). As a result they do not thin out at high shear rates and therefore provide a thicker lubricant film.

7. It is a myth that high detergent oils should not be put into a dirty engine because they will loosen the dirt and cause problems in the engine (any more than washing very dirty hands will block the drain). First, ALL oils meeting the latest API specs are almost by definition high detergent oils; diesel engine specs call for slightly higher detergency because of diesel soot, but the difference is slight. So, unless you've been buying your oil in outer Mongolia, you've had a detergent oil in your engine all along. Second, detergency means that the oil solubilizes the sludge and keeps it in ultrafine suspension; it doesn't loosen up big chunks of sludge (which would be caught in the filter even if it did). This myth comes from the good old days of yore 30 years or so ago when detergent oils were first introduced. If you're still concerned, just change out the oil a little sooner the first time.

8. All reputable engine oils are so good nowadays that if one uses the recommended oil viscosity, changes the oil regularly, and does not let it run low, car engine lives of 2 - 300,000 miles are readily achieved. The greatest problem is that many of us don't do that.

9. Honda's oil is of course not made by Honda, but it meets all the appropriate API specs and will provide excellent service within the constraints of 8. above. It is a high detergent oil.

10. My own preference is to use a synthetic oil because I have seen first hand their superior performance and I believe it more than justifies the additional cost. In my cars I extend the recommended oil drain interval by a factor of 2; in my Honda BF130 I change the oil at 200 hours as called for. Although any reputable true full synthetic oil will be superb, for reasons made clear below, I use Mobil 1. I sold my last car at 205,000 miles, and my three current vehicles are at 145,000, 128,000, and 100,000 miles, respectively. None have had engine failures of any kind. The BF130 is now at about 520 hours.

11. The basis for my opinions above is my 30 years with Mobil Oil, including 15 years in fundamental lubrication research and 15 years in lubricant (automotive, aviation, and industrial) product development. I managed the Division which, for example, developed (and continues to improve) Mobil 1. I retired 10 years ago.

Patrick

[Dora~Jean]

Patrick, thank you for taking the time to explain oils and their various characteristics. Much of what you said matches my own experience and knowledge of oils, dating back about 30 yrs. I worked at a Standard Station (factory Chevron) for 5 yrs while I went through Engineering school. Chevron provided excellent training on their oils which included a lot of what you said about viscosity, breakdown and sludge. Way before synthetics. I also did a term project on oil viscosity in my hydrodynamics class. Breakdown under high stress or longevity wasn't tested, but various viscosity indexes at a range of temperatures was accurately tested, graphed and reported.

I have 180,000 on my Jeep Cherokee, always used Castrol 10-30 or 10-40, but change it and filter not more than 6,000 miles (most freeway). I have recently changed to Mobil 1 for both my Harley and Yamaha outboards simply because I think it is a better oil and costs about the same when you add "Harley" to the name or "marine" to the application!

Thanks again.

[Sawdust]

Patrick,

I certainly agree. Mobil 1 (sometimes Amsoil) all the way - my land vehicles all go 200k miles+ and only synthetic used in outboard and inboard engines. I use a secondary bypass filter system in the trucks (probably a waste), but the oil looks super-clean at change time. 10,000 to 20,000 bucks for an outboard and using cheap oil just doesn't fit my budget

Dusty

[willhave1day]

[Alasgun]

Currently i am a Royal Purplite, but have run Delo400, Mobil 1 and others in my Chevy's over the years and dont get rid of them until they go over 200,000. Some have gone way over and I think the reason is diligence in maintenance. Next season I will have sufficient break in time on the 150 Honda and will change it over to Royal Purple as well. Mike on Huda Thunkit

[flapbreaker]

Wow, I feel like I've taken an oil bath. Good information from very qualified folks. Thanks for all the detailed info.

[Sneaks]

[oldgrowth]

Patrick (Cosmic C) - you certainly know your oils. This is not meant to start an argument with you and I would not dispute any thing you say, but while I have not had the formal education in oils you have, I base my opinions on my experiences.

My last engine failure was in 1974 on a 1972 International Scout. That was the year I started using DELO400. The Scout had 33,000 miles on it and it had a bad clicking noise in the engine. The dealer told me I needed an engine rebuild and it was 3,000 miles over the warranty. A old oil man suggested I use DELO400 in it and drive it until it quits. 110,000 miles later it was still going when I sold it.

My vehicles are run hard and put away wet. I do not baby them. The last vehicle I sold was a 1992 Jeep Cherokee 4 L. I towed a flatbed trailer loaded with lumber weighing 6500 lbs from Olympia to South central Washington several times a month. The Jeep spent a quarter of those miles on rough logging roads. I changed the oil in it, between 7 and 10,000 miles.

As I stated in an earlier post, 300,000+ miles is not uncommon for me to put on a vehicle before selling it. I consider it just broke in at 150,000 miles.

When Mobil 1 or some other kind of oil will give me better service than that, I will think about using it.

[Chester]

As outboards don't have catalytic converters (yet) to plug up, at least one oil company, Amsoil, puts extra zinc and phorsphorus in its outboard oil for added wear resistance.
Dunno if the diesel oils have this enhanced additive package.

[james]

Have used this stuff for years in everything I own.
I swear by it.

http://www.prolong.com/Main.aspx

click on "about us" then "technology"
there is also a video near the bottom of the page.

James

[Wefings]

Aftermarket oil filters will void your engine warranty .Its not worth it . Almost every 4 stroke catastrophic failure we have seen has had an aftermarket filter on it . Its kind of coincidental cause my service manager and I were speking about it this morning . Marine engines also run cooler than automotive engines which is why the have marine specs for oil .
Marc