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Marine Lubrication

Old 07-16-2005, 06:17 PM
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Arrow Re: Marine Lubrication

STATES OF LUBRICATION


HYDRODYNAMIC LUBRICATION

The design of oil is to produce a film of oil between two mating surfaces which gives
you the best protection against wear and creates a
hydraulic pressure (elasto-hydrodynamic lubrication,EHL) between the two surfaces.

Now under perfect conditions this type of lubrication will not allow wear. But in reality,
this is not always the case.This takes us to the next state of lubrication.

MIXED FILM LUBRICATION
This is where lubrication is marginal. Under load conditions oil is squeezed under pressure. For example, during accelleration of an engine, you step on the gas and the engine dumps fuel, in turn the force is increased against the rod bearings, pushing (or squeezing) on the hydrodynamic oil creating a marginal lubrication condition. This is under normal use. But what happens to oil when it is under extreme pressure created by abuse or just a heavy foot?

BOUNDARY LUBRICATION
This is where lubrication is dependant on antiwear additives. What happens here, is lubrication can be put under so much pressure, and is momentarily squeezed out to such a point that if oil didn't have any antiwear additives, you would be metal to metal. This is the last line of defense for lubrication to protect your equipment. A common place where you see a lot of high levels of barrier lubricant is in gear lubes. Ever wonder what that rotten smell was? Yep, high levels of zinc, and phosphorus. These are the two most used antiwear wear additives used in oils today.

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Old 07-16-2005, 06:18 PM
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Arrow Re: Marine Lubrication

How does an oil 'lose' some of its viscosity in a engine?



Shear stability is a measure of the amount of viscosity an oil may lose during operation. Oil experiences very high stresses in certain areas of the engine such as in the oil pump, cam shaft area , piston rings, and any other areas where two mating surface areas squeeze the oil film out momentarily . Most multigrade engine oils contain special types of additives, called Viscosity Index Improvers, which are composed of very large, viscosity-controlling molecules. As the oil passes through the engine, these molecules are permanently sheared or torn apart over time, causing the additive to lose its viscosity-contributing advantages which reduces the oils ability to maintain its higher number.

Synth Oils do not rely as much on special Viscosity Index Improver additives and will experience little permanent viscosity loss.

The shear stability of an oil is measured by using both ASTM test methods D445 and D5275. First, the viscosity of an engine oil is measured. Then, the oil is exposed to severe shearing conditions by repeatedly pumping it through a specially-sized diesel fuel injection nozzle at high pressure. After shearing the oil, its viscosity is measured again. The percentage of viscosity lost is determined by comparing the second viscosity measurement with the original viscosity measurement.

Although there are no specifications indicating required levels of shear stability for engine oils, lower percentages mean that an oil is more shear stable and will retain its viscosity better during operation.

Bellow Oil is being sheared or squeezed out momentarily around the rings, also when the piston pushes down against the crank, it squeezes out the film around the top rod bearing allowing the bearings to scuff or wear.
So does What does this shearing do to your oil and engine in the long term?

When the oil film is sheared or squeezed out, then your protection is now reliant on barrier lubricant additives. Oil has 3 states of lubrication , Hydrodynamic, mixed film, and boundary(barrier). The best is Hydrodynamic which is nothing more than a flow of oil separating two mating surfaces. After a period of time shearing, the oil will lose it's ability to hold up to the same flow as before since the VI Improvers are breaking down causing the oil to thin down in grade. Once this happens, there is less film strength between the mating surfaces so it doesn't take as much for the oil to shear, therefore creating more heat which attacks the base oil even more and then starts to cause the oil to thicken up due to the excessive levels of heat and the broken down VI Improvers become a contaminant which added to the existing oil will continue to thicken and ultimately cause sludge if not changed in a reasonable time..

A lot of people believe that a full synth oil can protect better than a mineral based oil. Lets look at that scenario.

If you have a 10w30 mineral oil, that means your base oil has measured to flow between 9.30-12.49 Cst's @ 100deg C.

If you take a synth 10w30 base oil, that means your base oil(synth) has also measured to flow between the same 9.30-12.49 Cst's @ 100 deg C.


What this shows is that when the piston is forced down from the explosion created by your spark plug a lot of pressure is being applied through the upper rod bearing against the crank to make the engine go. Now when the piston is on the up stroke, the other pistons are pushing the crank around so there is no real pressure on the bottom causing the oil to shear or squeeze out on the bottom bearing so there is very little wear against the bottom.

So What does protect your engine when the hydrodynamic film is sheared?

After the base oil has sheared or squeezed out, The last line of defense is an additive that puts down a barrier film. This additive usually has higher levels of strength against shearing so it helps keep the wear down. Alright, here's the catch. In 96, the lubrication industry changed from the SH to SJ API rated oil by reducing the barrier lubricant additives to help preserve cat converters on cars. Why?, It appears that the manufactures / lubrication experts are concerned with contaminating the cat converters with the standard antiwear additives in the motor oils so they have reduced the levels of antiwear additives to preserve the cats. Hmmm, guess what, When they introduced the new SL GF-3 oils, They left it the same. Ok, not out of the woods yet... GL4 oils were introduced around April 2005. Have a guess one of the things they are going to do?, YEP, reduce the current antiwear additives again.

The interesting thing to note is that more and more oil companies are coming out with higher mileage motor oils with higher levels of the antiwear additives. Catch is, they are not API certified there fore can void engine warr's.

Remember all those additive companies selling their miracle oil ? For some of them, they were doing nothing more than adding a barrier additive to your existing oil. Problem there, too much of a good thing can cause it to overload the blend that the oil company started with, so a lot of times the detergents in the oil are not able to do their job and fight acids produced by the engine, there fore the oil will oxidize faster and start the process of breakdown and extended oil drains are out of the question. not to mention engine warr issues again. Guess what a good race oil has... higher levels of antiwear and less detergents. Since they don't run race oils over the road, their not worried about oil drains. They change it constantly.



Conclusion:

The higher the spread between the bottom number and the top number the more VI improvers are relied on for maintaining the viscosity. Better to keep the numbers closer.

All base oils film strength will shear under stress or pressure. The real way to help prevent wear is to maintain higher levels of antiwear additives This in conjunction with a good base stock which resists breakdown to high heat.

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Old 07-16-2005, 06:19 PM
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Arrow Re: Marine Lubrication

MOLYBDENUM DISULFIDE

Molybdenum is a very hard metal with a number of industrial uses:
It is combined with chromium in steel to make the steel harder and more resistant to bending. Most of the bicycle frames produced today use chromium and molybdenum steel. Because the steel is so much harder, the manufacturers can use less, thereby making the frame lighter.
Molybdenum Disulfide (Moly) has been used for decades in lubricating pastes and greases because it is slippery and forms a protective coating on metal parts:
Moly exists as microscopic hexagonal crystal platelets Several molecules make up one of these platelets. A single molecule of Moly contains two sulfur atoms and one molybdenum atom. Moly platelets are attracted to metal surfaces. This attraction and the force of moving engine parts rubbing across one another provide the necessary thermochemical reaction necessary for Moly to form an overlapping protective coating like armor on all of your engine parts. This protective armor coating has a number of properties that are very beneficial for your engine.
The Moly platelets that make up the protective layers on your engine surfaces slide across one another very easily. Instead of metal rubbing against metal, you have Moly platelets moving across one another protecting and lubricating the metal engine parts.
This coating effectively fills in the microscopic pores that cover the surface of all engine parts, making them smoother. This feature is important in providing an effective seal on the combustion chamber. By filling in the craters and pores Moly improves this seal allowing for more efficient combustion and engine performance.
This overlapping coating of Moly also gives protection against loading (perpendicular) forces. These forces occur on the bearings, and lifters. The high pressures that occur between these moving parts tend to squeeze normal lubricants out.


Eventually, there is metal to metal contact, which damages these moving parts and creates large amounts of heat. Fortunately, this is not the case with some lubricants.The layer of moly that forms on these moving surfaces can withstand pressures of 500,000 psi, without being squeezed out.

Engineers and scientists have tried for years to use Moly in motor oils but they have been unsuccessful because they could not find a way to keep Moly in suspension. Once Moly was put into suspension it would gradually settle out. It was easy to see it come out of suspension because a black sludge would collect on the bottom of the oil containers. In engines it would settle to the bottom of the crankcase or clog oil pathways and filters.
Engineers have overcome these obstacles. They have developed a process that keeps Moly in suspension and isn't filtered out. Since that time the product has undergone extensive independent testing in labs and in the field for many years to insure that the product stands up to the rigorous needs of today's engines. With the plating action of Moly reducing friction which reduces heat, this helps keep rings free from carbon buildup, prevents blow-by, decreases emission, and extends oil life.
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Old 07-16-2005, 07:54 PM
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Default Re: Marine Lubrication

Originally Posted by vandy021
The publicity I think moved all my red cap. I think it's all gone!!!

You told us to wait till the 26th?
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Old 07-16-2005, 08:17 PM
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Arrow Re: Marine Lubrication

The reason I am custom tailoring an educational site for us is because Offshore boats have very special needs that even Bob's site does not pretend to address. I hope you all take the time to read up on things.

I eventually want you all to be able to be familiar enough with what goes into a lubricant to be able to research it and make your own choices. I will be here for any questions as usual.
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Old 07-16-2005, 08:21 PM
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Arrow Re: Marine Lubrication

I received a question concerning a high performance oil for supercharged applications designed for racing.

Here is a suggestion or two:
Amsoil SAE 60 Super Heavy Weight Racing Oil.

http://www.amsoil.com/storefront/ahr.aspx

Redline 60WT race oil

http://www.redlineoil.com/products_m...46&subcatID=15

Usually used for the race and changed as they only have enough additives for a very short period of time but during that time offer extensive protection.
Attached Thumbnails Marine Lubrication-ahr_qt_300pxh.jpg   Marine Lubrication-66.jpg  

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Old 07-16-2005, 08:29 PM
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Arrow Re: Marine Lubrication

Originally Posted by vandy021
The publicity I think moved all my red cap. I think it's all gone!!!
So much for your stash of Redcap....my extensive analysis shows Goldcap to be solid. I know others elsewhere previously swayed me to take a closer look..and to some extent I was concerned....but the fact is an independent lab says Goldcap has the same base and is only 30% less than V-Twin which is what Redcap always was. With Goldcap's analysis comes documentation that the 15W-50 has about the same ZDDP level of Redcap.

Sometimes false alarms happen. They are rare and usually have an explanation. I think Goldcaps Extended competitors were posting information to defend their best interests. To protect the market they created that Goldcap Extended now threatens. Goldcap data keeps coming in and it looks good...even though the data is good we still have posts that suggest otherwise and they are unfounded. This happens with any new product to some extent. Goldcap is looking good according to recent data.

Goldcap is a very good choice that may in time turn out to allow extended drains in the marine application as well but it is too early to tell.

I am sorry for the scare..but it is over..Goldcap is going to be very good especially at the 25-50 hour drains we do.

Happy shopping at Walmart and happy boating.

Last edited by Hydrocruiser; 07-16-2005 at 08:34 PM.
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Old 07-16-2005, 08:39 PM
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Arrow Re: Marine Lubrication

Amsoil's new 10W-40 & 10W-30 Marine oil to compete with Mercury and others in 4-stroke outboards

New AMSOIL Formula 4-StrokeŽ Marine Synthetic Motor Oils are premium quality synthetic formulations engineered for the harsh operating conditions of marine environments. They withstand the intense mechanical activity of continuous, high RPM operation to deliver superior viscosity protection. Formula 4-StrokeŽ Marine Synthetic Motor Oils are specially fortified with a heavy treatment of advanced additives that protect motors against wear, rust and deposits, and they excel in both high horsepower applications and all-day trolling conditions.

Looks like a great 4-stroke outboard oil.
Attached Thumbnails Marine Lubrication-wcf_qt_350px.jpg   Marine Lubrication-wcf_4ball_280px.jpg   Marine Lubrication-wct_qt_350px.jpg  


Last edited by Hydrocruiser; 07-16-2005 at 08:58 PM.
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Old 07-16-2005, 08:45 PM
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Arrow Re: Marine Lubrication

I was asked for another 20W-50 for racing that is synthetic but has more additives than a racing synthetic:


http://www.amsoil.com/storefront/tro.aspx

or

http://www.redlineoil.com/products_m...45&subcatID=14

Remember there are 2 grades...Highperformance...and "Racing"

Racing oils are for a single "race" usually. These oils here have more longevity built in.
Attached Thumbnails Marine Lubrication-tro_bottle_350pxh.jpg   Marine Lubrication-58.jpg  
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Old 07-16-2005, 08:54 PM
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Arrow Re: Marine Lubrication

Amsoils new 20W-50 motorcycle synthetic oil. Looks like a winner.
Attached Thumbnails Marine Lubrication-hitemp_viscos_mcv_300.jpg   Marine Lubrication-mcv_qt_350phx.jpg  
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