Oil Temp. vs Viscosity/Density WTF?

[Cadence]

Originally Posted by Wotname

How is the lubricating ability measured? In other words, what are the units of this factor?

I have been reading oil technical specifications for a few nights now and I am slowly coming to grips with some of the terms and how they are measured. I getting a reasonable understanding of the various ways of quantifying viscosity but I would love to fastback an understanding of lubricating ability and the method of quantifying it.

I also on the method of quantifying the ability to lubricate. It is probably not that complex.

[Wotname]

Originally Posted by Gounkoto

Viscosity is measured in C's or Centi Stock
Viscosity really means: resistance to flow.
All oils have two major factors to consider namely
SAE spec and API specs
SAE : Society of Automotive Engineering which refers to the oil's viscosity e.g. 10w40 etc.
API: American Petroleum Institution that refers to the additive package "cocktail" of the oil.
Yes, it is important to consider the operating temperature of a given component eg engine , gearbox etc. At the same time the ambient temperature where the component works should not be under estimated.
Also...as a rule of thumb, older engines that reach the final stage of their life cycle, respond better to mono grade SAE e.g. 30. It helps in cold start situation and builds oil pressure quicker during start up yet gives you the protection at the high end.
Be careful about using engine oil in gearbox, refer very closely to the OEM recommendation. Gearboxes do not require any TBN (total base number) that engine oil must have at the same time gearboxes require certain EP (extreme pressure) arditives in order to manage the load on the gears.... The same EP additives can be detrimental to your engine's life.
In summary: stick to the manufacturer's recommendation, stick to well known respectable brands of oil and try as much as possible to use the same brand of oil throughout the life of the components.
Do not save on oils and/or filters...

Welcome aboard CF, Gounkoto. Interesting first post and diving straight into an oil thread. I'm not sure if you have followed the many oil threads in the past and there are a zillion of them. Opinions vary widely on this subject and IMO, many are at the best, irrational - including most likely, some of mine . However I do try to keep to both detail and known facts even if though I occasionally misunderstand them and I try to stay away from generalisations (if possible).

Regarding engine oil in the gearbox, be aware that several manufacturers specify engine oil (both single weight and multigrade) in the gearbox, notably Yanmar in their smaller older gearboxes and also ones with wet clutches. Of course your summary is very accurate (IMO).

However I don't understand the section of your post which I emphasised above.

1. How does a mono single weight oil help in a cold start? The conventional wisdom is the opposite i.e. a multigrade offers less resistance to spinning up the engine (due to being "thinner") when cold thus allowing a higher rotational speed when cranking giving better compression thus easier starting. I am not really disputing your claim, rather I'm trying to understand the way you arrived at it.

2. Regarding building oil pressure faster, what is your reasoning (or evidence) for this?

3. Protection at the high end - what high end are you referring to? High temperature, high RPM, high hours, high section of the engines (rings, valve train, wrist pin) or high something else. If you are referring to high operating / high oil temperature, then surely a multigrade is theoretically better?

Again welcome aboard!

[Gounkoto]

Originally Posted by Wotname

Welcome aboard CF, Gounkoto. Interesting first post and diving straight into an oil thread. I'm not sure if you have followed the many oil threads in the past and there are a zillion of them. Opinions vary widely on this subject and IMO, many are at the best, irrational - including most likely, some of mine . However I do try to keep to both detail and known facts even if though I occasionally misunderstand them and I try to stay away from generalisations (if possible).

Regarding engine oil in the gearbox, be aware that several manufacturers specify engine oil (both single weight and multigrade) in the gearbox, notably Yanmar in their smaller older gearboxes and also ones with wet clutches. Of course your summary is very accurate (IMO).

However I don't understand the section of your post which I emphasised above.

1. How does a mono single weight oil help in a cold start? The conventional wisdom is the opposite i.e. a multigrade offers less resistance to spinning up the engine (due to being "thinner") when cold thus allowing a higher rotational speed when cranking giving better compression thus easier starting. I am not really disputing your claim, rather I'm trying to understand the way you arrived at it.

2. Regarding building oil pressure faster, what is your reasoning (or evidence) for this?

3. Protection at the high end - what high end are you referring to? High temperature, high RPM, high hours, high section of the engines (rings, valve train, wrist pin) or high something else. If you are referring to high operating / high oil temperature, then surely a multigrade is theoretically better?

Again welcome aboard!

Hi,
Regarding the highlighted portion of your reply (30 W oil in older engines). As the engine approach the end of the life cycle, the tolerances of the pistons, rings, cylinders, valves and guides as well as the oil pump clearances are all increasing. With that, you can expect that there will be dome loss of compression. Thus, thicker oil during start up will assist in "retaining temporarily" the compression that will enable the engine to start faster/better. At the same time, 30w oil will seal the gaps (wear) inside the oil pump better during cold start thus building up oil pressure quicker and providing the engine with better protection as the recommended oil pressure will be achieved faster.

Regarding engine oil being used in transmissions , especially those with clutches be aware... One of the tasks of the oil is to REDUCE friction (as well as to cool, clean and lubricate)
However, in a transmission fitted with clutches one of the major objectives of the oil is to ENHANCE friction in order to ensure maximum torque transfer. So... 2 opposite outputs requirements in two different environments...
Be aware..use the OEM recommendations.
Good luck.

[charliehows]

apologies, lost track of this thread; large thankyou to all contributors, I've found the thread most useful. One of my beefs is paying at least double for yanmars 30 monograde; I'll continue using it in the gearbox but I've already switched to cheaper 15-40 for the engine; I figure I'll change it more often because it's cheaper and easier to source.
once again, thanks.
charles.

[Wotname]

Originally Posted by charliehows

apologies, lost track of this thread; large thankyou to all contributors, I've found the thread most useful. One of my beefs is paying at least double for yanmars 30 monograde; I'll continue using it in the gearbox but I've already switched to cheaper 15-40 for the engine; I figure I'll change it more often because it's cheaper and easier to source.
once again, thanks.
charles.

Rather than pay double for the Yanmar product, you can the same grade (SAE 30, CD) oil for a much more reasonable price from Gulf Western Oil -an Australian company with the head office in Sydney.

Monoil 30 - SAE 30 - Gulf Western Oil - Gulf Western Oil

Unfortunately the minimum package size is 20 litres but perhaps you know someone you can share it with.

Maybe the per litre price is further reduced if you get the 250 litre drum or 1,000 litre IBC and be the local marina dealer of oil

[charliehows]

I recently did a waterway flush out with double strength vinegar, changed the oil to 15-40 and she seems to be running very nicely. Thanks for the info., I'll keep an eye out for affordable 30 mono but in the meantime the multigrade seems ok.

[Wotname]

Originally Posted by charliehows

I recently did a waterway flush out with double strength vinegar, changed the oil to 15-40 and she seems to be running very nicely. Thanks for the info., I'll keep an eye out for affordable 30 mono but in the meantime the multigrade seems ok.

Curious - where did you source the double strength vinegar?

[charliehows]

lol, i'm a cheap bastard, 2 litres for $2 at Coles...did the job nicely though and I think it's a bit safer to use than hydrochloric acid

[Wotname]

Thanks Charliehows, I didn't realise the supermarkets sold double strength vinegar, I must go and get some.

I have used regular vinegar as well as HCl and while the HCl is fast, I'm always nervous about using it on board. I'll look forward to using double strength vinegar.

[GordMay]

Originally Posted by charliehows

I recently did a waterway flush out with double strength vinegar ...

Interesting.
I’ve never seen “double strength” vinegar.
In Canada, regular white cooking vinegar is 5% acidity, and “cleaning” vinegar is 6% acidity. The one percent difference actually makes it 20% stronger.

[Compass790]

Originally Posted by Wotname

How is the lubricating ability measured? In other words, what are the units of this factor?

I have been reading oil technical specifications for a few nights now and I am slowly coming to grips with some of the terms and how they are measured. I getting a reasonable understanding of the various ways of quantifying viscosity but I would love to fastback an understanding of lubricating ability and the method of quantifying it.

Don't know the units for lubricity, wear scar tests are the closest I've come across.
Don't sweat it too much. How many YSe's do you think have failed from using mutigrade oil with a higher API rating than the original CD 30w single weight? Do you think oil has got worse over the decades?
But yes oil is a brain worm

[Compass790]

Originally Posted by charliehows

lol, i'm a cheap bastard, 2 litres for $2 at Coles...did the job nicely though and I think it's a bit safer to use than hydrochloric acid

I'm a cheap bastard too so i'll tell you i use Gulf Western SF/CF 20w-50 from super cheap auto in our Yanmar ysm8 with no problems.
it says you can substitute it for CD rated mono 30 on their website & it's available for peanuts at Supercheap Auto on special.
I'll put it in the gearbox too when the 15w-40 thats currently in there is due for a change. We have no clutch problems from using the 15w-40 ( 6 years) but i can see the argument why risk it if you want to use the 30 mono in the gearbox. Best to follow manufacturers recommendations if in doubt.

[charliehows]

i think thats a good question - "do you think that oil has gotten worse over the years?"
I'd have to say a resounding 'no', which is why we can be a bit relaxed about what we pour in. My rule of thumb for older engines has always been 'change the oil frequently and it'll run forever' - I suspect there is a lot of money and marketing going into convincing us that there is a great deal of difference in a product which is actually manufactured within a very narrow band of variation.
In spite of my own intentions, i reckon when my mono30 runs out the following gearbox change might be from the 'el cheapo' bottle too.

[Wotname]

Originally Posted by GordMay

Interesting.
I’ve never seen “double strength” vinegar.
In Canada, regular white cooking vinegar is 5% acidity, and “cleaning” vinegar is 6% acidity. The one percent difference actually makes it 20% stronger.

I found some "double strength" vinegar at Woolies (in Oz) today and while the bottle doesn't state the percentage, the product website states it is 8%.

https://www.woolworths.com.au/shop/p...-white-vinegar

Further google research suggests north american vinegar is normally 5% and full strength is 6% (as Gordmay posted) with a double strength occasionally available but no percentage was cited.

Then I found this reference which states Aussie and Kiwi regular vinegar is 4% (the minimum allowed by some food standard) and so it kinda fits that our double strength is 8%.

https://www.healthycanning.com/vineg...a-new-zealand/

And then there is Horticultural vinegar which contains 20% acetic acid but I haven't chased down any Oz supplier yet. Presumably available in Canada???
https://laidbackgardener.blog/tag/do...ength-vinegar/

FWIW...

[Compass790]

Originally Posted by charliehows

i think thats a good question - "do you think that oil has gotten worse over the years?"
I'd have to say a resounding 'no', which is why we can be a bit relaxed about what we pour in. My rule of thumb for older engines has always been 'change the oil frequently and it'll run forever' - I suspect there is a lot of money and marketing going into convincing us that there is a great deal of difference in a product which is actually manufactured within a very narrow band of variation.
In spite of my own intentions, i reckon when my mono30 runs out the following gearbox change might be from the 'el cheapo' bottle too.

Forgot to add that somewhere in the Gulf Western literature it says the 20w-50 CF is suitable for wet clutches as well.
I'm a gambler but didn't think I will be taking much of a risk putting it in the gearbox especially as decades ago I used to use 20w-50 in my Kawasaki 900 with wet clutch that got a much harder time than the yanmar.
Think of the millions of earthmoving machines using standard 15w-40 under much more extreme conditions than your marine diesel & relax when you dont let Yanmar ream you for "their" super special engine oil. Just sayn....