Correct gearbox oil ?

[Widowmaker]

I have a WS 1971 Silver Century Seagull 4.5hp.

Can i use SAE 85W140 Mineral Gearbox oil for the bearbox ?

Regards

Jesse

[Vic]

Not a wise idea. The WS should use a 140 oil.
The trouble with your suggested multigrade is that it only has the viscosity of a 140 oil when it is hot. Outboard engine gearboxes are fairly well cooled so tend not to get hot like an automotive gear box does.

Agricultural suppliers can usually supply 140 grade oil. It is also available for old vehicle enthusiasts

Silkolene market Rhino 140 oil http://www.opieoils.co.uk/p-835-silkole ... r-oil.aspx

Morris Lubricants market Golden film AG140 http://www.morrislubricants.co.uk/scrip ... Product=26

[Horsley-Anarak]

It only has the viscosity of a 140 oil when it is hot.

??

Low number low viscosity, high number high viscosity.

If all I had was 85w 140 then I would use that.

The worst thing that can happen is it might leak out a little faster.

I personally feel that as long as the gearbox has oil in it when it runs, that is all that matters.

Better to use "any" oil, and replace it regular intervals. The main reason for gear failure will be salt water and no oil.

So before you use the engine, check the oil and before you store the engine drain any contaminated oil.

H-A

[Widowmaker]

Hey thanks all. I scored some 140 Gearbox oil so all good. Ill drain both fuel and gearbox prior to storing between use.

Thanks for the good avice.
Jesse

[charlesp]

I strongly suspect that viscosity isn't the only issue here.

The right oil should have the ability to form an emulsion with water. An oil that doesn't shouldn't be used.

[Vic]

I strongly suspect that viscosity isn't the only issue here.

The right oil should have the ability to form an emulsion with water. An oil that doesn't shouldn't be used.

So what information in an oil specification should we be looking for to ensure an adequate ability to form an emulsion?
A high demulsification number? If so how high?
Are demulsification numbers normally quoted?

[Hugz]

I recall doing a bit of research on this in the past. I believe I came to the conclusion that the product required was generally Stern tube oil. Hard to come across and pricey unless you know any tug/ship owners.

From http://www.gannonoils.co.uk/Marine/Ster ... e_Oil.html

Castrol Coral 2 Stern Tube Oil

Coral 2 stern tube oil is designed to readily emulsify with seawater thus providing certain advantages over oils selected for demulsibility in a wet environment.Firstly, oil/water emulsions provide a higher viscosity fluid than neat oils thus minimising oil loss or water ingress.
Secondly, by sustaining an oil/water emulsion, corrosion from separated seawater, which can occur in a statically loaded sterntube bearing, is avoided.

APPLICATIONS
This grade has given satisfactory service in stern tubes employing a wide variety of seals including Cedervall, Chuetsu-Waukesha, and Simplex Compact Seals.
Coral 2 has other applications in the marine environment, including the use in fin stabilisers and propeller hubs.

FEATURES/BENEFITS
Blended from selected mineral oils compounded with a natural emulsifier, this lubricant gives a stable high viscosity emulsion and good rust protection.

Then you have to consider whether the oil will emulsify with salt or fresh water. Personally, I just stick to Penrite and change regularly.

[charlesp]

Vic I don't know the answer to that, it was more a random musing...

[Vic]

Vic I don't know the answer to that, it was more a random musing...

It an intersting and valid point though.

They tell us we should use an outboard engine gearbox oil most of our other makes of outboard engines rather than an automotive gear oil because it contains corrosion inhibitors to guard against the effects of water ingress and additional emulsifiers to ensure that any water forms a ( stable) emulsion.

My only contact with emulsifying /demulsifying properties of oils has been ( long ago) in connection with steam turbine lubricating oils where one is looking for a quick separation of oil from an emulsion

Hugz suggest Castrol Coral 2 stern tube oil but it is rather light having a viscosity of 222 cSt at 40C ... pretty near the middle of the viscosity range of SAE 90 gear oils. An SAE 140 oil would be somewhere in the range 350 - 700 cSt at 40C.

He also suggests Penrite, presumably meaning Transoil 140 which has a viscosity of 480 cSt at 40C. Penrite is an Australian brand .

Goodness knows where one would get Castrol Coral 2 or Transoil 140 in the uk

[Hugz]

Your are right. Penrite seems to have closed down there UK distribution network. Here are/were their details.

Penrite Oil Co.
Hang Hill Works, Bream,
Nr Lydney, Glos.
GL 15 6HT

Website: www.penrite.co.uk
Email: penriteoil.uk@penriteoil.com
Ph: +44 (0) 1594 562357
Fax: +44 (0) 1594 564234

Mobil is probably better suited.

<i>Mobil Stern Tube Lubricant
Product Description

Mobil Stern Tube Lubricant is a high performance, high viscosity lubricant developed especially for the lubrication of Cedervall-type stern tube bearings used in ships and for certain bearings of ships' fin stabilizers. Mobil Stern Tube Lubricant is formulated from relatively high Viscosity Index (VI) base oils combined with emulsifiers, structure modifiers, surface active agents and corrosion preventives. It emulsifies readily with seawater to form a stable water-in-oil emulsion that is adhesive and an excellent lubricant. It provides effective rust protection in the presence of seawater and the lubricating film is resistant to water washing so that corrosion protection is maintained for extended periods under severe operating conditions.

Where the propeller shaft passes through the hull of a ship, it is supported by a bearing that is housed in the stern tube. Three distinct types of bearings are employed in this application: 1) The lignum vitae bearing, which has a stuffing box on the inboard side and no seal on the outboard side, is lubricated by seawater. The stuffing box may be lubricated with grease or oil, if this is deemed necessary. 2) Bronze or white metal bearings having oil-tight rubber seals on the inboard and outboard ends normally are filled with a lubricating oil that readily separates from water. Turbine oils, engine oils or hydraulic oils of the required viscosity generally are recommended. 3) The Cedervall type, which is a bronze or white metal bearing having an oil-tight inboard seal or stuffing box and metallic outboard seal that is not fully oil-tight, requires a lubricant that readily emulsifies with water. Mobil Stern Tube Lubricant has been formulated to meet this need. With the Cedervall type bearing a high viscosity lubricant generally is supplied to the bearing from a gravity tank located above the waterline so that the lubricant is under sufficient pressure to help exclude water from the bearing.

A recent development in ship stabilizers is the Denny-Brown-AEG stabilizer developed jointly by Brown Brothers and Co. Ltd, William Denny and Brothers Ltd., AEG, and Deutsche Weft. In these newer designs, the fins are mounted on trunnion bearings which permit them to be folded forward into storage boxes in the hull of the ship when not in use. A fixed shaft extends from the crux trunnion and the fin is mounted on this shaft on two bearings, which permit the fin to be tilted by a hydraulic mechanism to provide the righting movement to reduce roll of the ship. The interior of the fin and the fin bearings are lubricated by gravity from a header tank located above the waterline and the crux trunnion bearings are lubricated by pressure feed from a lubricator pump.
Features and Benefits

The requirements for lubrication of these three sets of bearings in the stabilizers and stern tubes are sufficiently similar so that a single, carefully formulated lubricant can be used for all of them. To perform satisfactorily, however, the lubricant must have the correct viscosity to flow properly under gravity head without excessive rapid flow that would result in high consumption; must minimize wear under the heavy loads encountered in the bearings; must protect the bearings and other components from corrosion and must emulsify with any seawater that passes the seals in order to maintain lubricating characteristics and minimize corrosion.

In stern tube applications, consumption of the lubricant is a major concern, both from the standpoint of the cost of the lubricant and the cost of labor required to fill the tanks. In two ship trials conducted over an extended period, Mobil Stern tube Lubricant gave significantly reduced consumption compared to the previous formulation, and at least as low as the best competitive product. Throughout the tests, lubrication was entirely satisfactory. These results indicate that Mobil Stern Tube Lubricant provides effective and low cost lubrication of stern tube bearings.

Key features and potential benefits include:
Features Advantages and Potential Benefits
Selected viscometrics Effective lubrication of critical stabilizer and stern tube components
Good emulsification properties Emulsifies readily to maintain lubrication in the presence of seawater
Excellent rust and corrosion properties Protects critical bearing surfaces exposed to seawater
Multi-use capability Reduces the number of lubricants required on-board
Good viscosity retention in severe applications Effective leakage control and reduced oil consumption

Applications

Mobil Stern Tube Lubricant is recommended for the lubrication of Cedervall-type stern tube bearings on ships where a high viscosity, readily-emulsifying lubricant is recommended by the manufacturer. It is also recommended for the lubrication of fin tilting bearings, as well as the crux trunnion bearings of Denny-Brown-AEG ship stabilizers and is approved by the manufacturer for use in these applications.
Specifications and Approvals

Mobil Stern Tube Lubricant has the following builder approvals
Brown Brothers and Company, Ltd.
William Denny and Brothers Ltd.
AEG
Deutsche Weft


Typical Properties

Viscosity
cSt @ 40ºC 385
cSt @ 100ºC 24
Viscosity Index, ASTM D 2270 82
Pour Point, ºC, max, ASTM D 97 10
Flash Point, ºC, min, ASTM D 92 246
Density @15ºC kg/l, ASMT D 4052 0.915
API Gravity 23.1
Rust Test-Seawater, ASTM D 1401 Pass
Timken Salt Water Corrosion Test Pass
Emulsion Test, ASTM D 1401
Emulsion @ 60 min, ml 60
Emulsion characteristics Thick and Stable</i>

[Hugz]

Here is another interesting thread on the subject:

viewtopic.php?f=2&t=2276

[croweater]

The dealers here when servicing and pre delivering British Seagulls used Shell Strombus K78 they
also added a tea spoon of water to make the oil emulsify straight away. The K78 is no longer available
Shell do list a Strombus MP which is a stern tube oil it has a viscosity of 273 is this too thin for the
Seagulls that recommend viscosity 460 (auto 140).

What do the guys use that race them?

Has anyone tried to convert the gearboxes to sealed units?

John

[Hugz]

Pretty sure this is a century sealed factory box that uses 90 grade oil. Alas no longer with me.

[Gannet]

It certainly seems difficult to find out how a specific grade/supply of SAE140 oil performs in respect of emulsifying.
If one is worried about it, I would suggest that drain the gearbox oil into a glass jar; put it on a shelf and observe over weeks/ months how it separates out.
I think what happens is that it separates out into different layers:-
The top layer is oil.
Next is a water in oil emulsion.
Next is a oil in water emulsion.
Next is water.

With the oil that I use (some Gulf Ultragear 1000 SAE 140 from the back of the garage that I obtained for use in old car boxes);
the separation takes many weeks and the layers are quite distinct. I have only once seen the bottom water layer.
If one is short of oil (or environmentally concerned or just tight!) the top layer I reckon can be reused.
Doing this with different oils might be helpful.
Jeremy