Lower unit lube experiment

[Lion hunter]

Just to add to my encylopedia of worthless knowledge I decided to try an experiment with supertech marine 80-90w and BRP Hi-Vis. I put a 1/4 cup of each in a water bottle with a 1/4 cup of water,and shook vigorously for 2 minutes. Here are the results (The BRP is on the left)
1. Starting off the supertech was translucent and very sticky, The BRP was not translucent.

2. The BRP began to separate within 30 sec. after shaking
The supertech shook into a foam within a minute and it actually was hard to shake (like 2
part floatation foam). It did not start to separate for 15 min.

3. The separation on the BRP never fully occured the water remained milky for an entire 1.5 hrs
As separation occured on the supertech it fuuly seperated in oil and clear water. Almost Full separation within an hour.

Interesting how much the BRP expanded and seperated into 3 parts after 1.5 hrs. But even then there was oil suspended in the water at the bottom. The supertech was pretty much clear.

Here are some pics

Start of experiment, BRP on left

1 min after shaking

30minutes after shaking

1.5 hrs after shaking

 

[marcortez]

Re: Lower unit lube experiment

With your testing as reference, what gear oil would you want in your outboard's lower unit?

 

[kenson]

Re: Lower unit lube experiment

I have seen some lower unit leaks in my limited time. What are you saying on the results of this.

 

[ajgraz]

Re: Lower unit lube experiment

Two things I's like to see:

1) A Control (80-90w automotive gear oil; i.e., with no emulsifiers); without that I don't see that we can say that either of these lubes did anything special to emulsify the water.

2) Also done at a concentration like 10 (or even 20) parts oil to 1 part water; I'm thinking that might better simulate a LU leak?

 

[Lion hunter]

Re: Lower unit lube experiment

My opinion is 1st: I overwelmed the oil with water, no amount of emulsifiers can take 50% water.

As you can see from the BRP oil it took all it could and immediatly started separating when I quit shaking But only about 30% of the water I put in there separated the rest stayed in emulsion. The BRP stayed viscous throughout the shaking. And even several hour later the BRP seemed to hold about 20% of the water in emulsion. The 30% that separated was still filmy with oil and you could not see through it.

The supertech seemed to emulsify everything but it got so thick and foamy I can just imagine the pressure that would create in a geat box. It did not separate as quick but when it did it separate completly within hours.

So my opinion is...... I think that the BRP has better emulsifier properties. It quickly takes all the water it can hold and doesn't let go of it. The super tech seems to try and keep taking water and just makes a hard very thick foam which I can't imagine would be good for a lower unit. So I think I may switch to BRP. I'm gonna get some sythetic 80-90W GL-5 differential lube and compare to the BRP just to add something else to my worthless knowledge.

 

[Lion hunter]

Re: Lower unit lube experiment

Two things I's like to see:

1) A Control (80-90w automotive gear oil; i.e., with no emulsifiers); without that I don't see that we can say that either of these lubes did anything special to emulsify the water.

2) Also done at a concentration like 10 (or even 20) parts oil to 1 part water; I'm thinking that might better simulate a LU leak?

I'm gonna try that next with GL-5 rated standard and synthetic gear lube for autos (probably mobil 1). Although they both did have emulsifying properties because the water and oil joined (the oil took all it could and that wasn't 50%). I did 50% as I figured that would be an extreme intrusiuon of water.

Just went out and looked at the bottles. The separation that took place in the BRP in the 1st 1.5 hrs has remained the same for about the last 10, and the water portion is still milky. The supertech continues to separate and the water portion is completly clear. I'm convinced that the BRP has better emulsifying properties than supertech. As far as lubricatiing properties I have no idea.

 

[seahorse5]

Re: Lower unit lube experiment

just shaking up a bottle of water and oil does is not the same as the churning it gets through a set of high-speed rotating gears. I've seen various oils take over a week to separate after running in a gearcase.


Here is the best test anyone has done using different lower unit oils. The graphs are small and hard to read but they are explained in the story.

http://bwbmag.com/output.cfm?id=1891729&sectionid=308

 

[Lion hunter]

Re: Lower unit lube experiment

just shaking up a bottle of water and oil does is not the same as the churning it gets through a set of high-speed rotating gears. I've seen various oils take over a week to separate after running in a gearcase.

You are correct. I was just suprised at hard stiff and foamy the supertech got by just shaking it for 2 minutes. This was in no way meant to be scientific or prove anything it was just something I did for the heck of it to see what would happen and compare the 2 oils I had on hand.

I wish I could see the charts on that page, it's an interesting read.

 

[JustJason]

Re: Lower unit lube experiment

Throw some Mercruiser High Performance gear lube in the mix and you'll see that it's the clear winner.

 

[ghostchaser]

Re: TRIM FLUID REPLACEMENT

Re: TRIM FLUID REPLACEMENT

Can anyone tell me how much trim fluid should fill the resevoir for a 40 horse mercury bigfoot engine?

 

[Lion hunter]

Re: Lower unit lube experiment

ghostchaser start a new post in the Merc section and they can help you there.