Oil Analysis Volvo Aqumatic-interesting results

LegacyT

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Some food for thought. I drained and sent out an oil sample for lab testing to see if I should be concerned about rebuilding my drive since I saw some fine metal in the oil. Apparently the metal content was quite low for the sample and the "machine condition" passed with no problem. However... I ran this drive for ~40 hrs since the last oil change. Volvo recommends 200hr drive oil change intervals for the SP aquamatic. The "lubricant condition" however was "marginal". The measured viscosity level was very low. Possible causes were from thermal cracking of oil molecules, or shear thinning of viscosity improvers... The oil used was Castrol GTX 10w40. I know nothing destroys oil quicker than gear sets hence why motorcycles demand specialty oils with shared motor/transmission oil. But didnt expect to eat through it so quick, especially since Volvo recommends "same as engine" oil. So for you guys running older SP drives with motor oil maybe consider running a higher quality one. I figured oil was oil but I was completely wrong... Just something to share.
 
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Walt T

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Re: Oil Analysis Volvo Aqumatic-interesting results

You weren't wrong. You're going by sight. The lab is going by science. They basically said you didn't need to drain the oil. Sight is not a good indicator of oil condition. That said, there is absolutely no harm in changing it more frequently and you did absolutely nothing wrong. Like you say, it is interesting. I highly recommend oil samples and learning how to decipher them.
 

LegacyT

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Re: Oil Analysis Volvo Aqumatic-interesting results

I would have never figured that the drive would kill this quality brand name oil so quickly. A good heads up for the future and guys putting a lot of hrs on their boats with similar setups.
 

jeffnick

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Re: Oil Analysis Volvo Aqumatic-interesting results

Wolf - wolf!

My 40 year old drive has likely run om the same motor oil for years at a time. I'm thinking 'marginal' lubrication quality must be plenty for this old technology. You've not convinced me to worry even a little about my seasonal drive oil changes.
 

jerryjerry05

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Re: Oil Analysis Volvo Aqumatic-interesting results

Doesn't that drive require 30wt.
 

Lou C

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Re: Oil Analysis Volvo Aqumatic-interesting results

Its a well known fact that dino multi vis oils shear down in use and it may be the type of gears that are used in the old style Volvo transmission are more likely to shear down oil. So I'd be inclined to use a straight 30 if they do in fact recommend motor oil instead of a gear oil. I think its odd that Volvo recommended motor oil since when you think about it, motor oil in an engine is not subject to the same type of wear that hypoid gears (if that's what they use) create. No other company that produced outdrives (OMC, Merc) recommended anything lighter than a 90 w oil for their drives.
 

K-2

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Re: Oil Analysis Volvo Aqumatic-interesting results

Legacy this is the boat in your sig?
I find it interesting that the SX-A1 recommends 90 wt. and the 270 is 30 wt.
The 270TE is 90 wt. I'm curious what is different inside these out drives? What parts
inside were changed so that they would recommend 90wt.?
What would happen if you switched to 90 or 75W-90 synthetic?
 

billbayliner

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Re: Oil Analysis Volvo Aqumatic-interesting results

What would happen if you switched to 90 or 75W-90 synthetic?

The SP-A1 calls for:
Oil:
Same as engine
Qty: 2.6 liters (2.74 US qts)


The SP-A2 calls for:
Oil:
Same as engine or
Synthetic Gear Oil
API GL-5 SAE 75W?90
Qty: 2.6 liters (2.74 US qts)


There is no difference in the pumping system in these 2 drives. Only difference is sliding sleeve, upper gear set, and shift cover.

I would use the the fully synthetic 75W90 gear oil as the clutch assembly has a problem varnishing up with traditional oils. I can tell right away when I pull an upper apart and take a look at the clutch assembly if synthetic or traditional oils have been used. When I see the varnish I make a point of asking what oil has been used over the years.

It has proved my theory.

Volvo states it is fine to use and the cost is only a few dollars more. I pick up fully synthetic gear oil for about $13 at the local auto parts store.
 
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jeffnick

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Re: Oil Analysis Volvo Aqumatic-interesting results

I had a cone clutch in my sailboat transmission (10 hp Westerbeke diesel). After a few years it would sometimes not engage. The change from gear oil to engine oil solved the problem. Came to find out there was a TSB to do the change, but I never got it until after I took the trans out for 'repair'. I figured it had more to do with the chemistry/viscosity of the oil effecting the cone grip -- that transmission was totally horizontal.
 

billbayliner

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Re: Oil Analysis Volvo Aqumatic-interesting results

After the SP-C Volvo states to use only fully synthetic 75W-90 gear oil in the SP (single prop) drives.

All DP (Duo Prop) unit are to use FULLY SYNTHETIC 75w-90 gear oil ONLY.

If you want to stick to "same as engine" grade of oil, go with the synthetic.

I usually take photos to document the upper rebuilds. I will try and find a picture of the cups and sliding sleeve of the clutch assembly from a unit that used conventional oil instead of the called for synthetic.

Here is a photo of an upper I rebuilt last spring. It was in working order when I rebuild it. Was rebuilt as preventative measure as the bellow had split and water was introduced to the U/J assembly. Also corroded the sealing washer and water was starting to enter the drive.

Notice how black the cup is?

DSC03028_zps6b201d88.jpg
 
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Walt T

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Re: Oil Analysis Volvo Aqumatic-interesting results

That is a very good picture that illustrates that oil is not just used to lubricate, it is also used to cool parts by carrying heat away from them back to the reservoir, wherever and whatever that may be so it can give up that heat safely.

The reason synthetic oil is "better" than standard oil is the length of the molecule. Synthetic oil has a very long molecule chain which makes it substantially stronger that Dino oil. It is that strength that allows it to last much longer, hold much more debris and stand up to excessive heat much better than standard oil.
That said, There is nothing wrong with standard oil either. What is more important are regular maintenance intervals. Sometimes (me included) owners will simply not check oil level or take a look at air filters and belts because of the sense of security using synthetic oil gives. I know I can go 5000 miles between oil changes easy, but that means I'm not looking under the hood as frequently. Now I know I'm talking about motors, but this applies to drives also. You still need to check for water contamination at the same intervals by loosening the drain plug a little and seeing if water seeps out. Using synthetic and still changing oil at the same intervals is fine, but kind of a waste of your money. Anyway, just food for thought, I know it's kind of an irrelevant tangent.
 
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LegacyT

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Re: Oil Analysis Volvo Aqumatic-interesting results

Hi billbayliner, I sent you a pm but your inbox is full
 

billbayliner

Chief Petty Officer
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Re: Oil Analysis Volvo Aqumatic-interesting results

I just cleared out the inbox and sent you my email address
 

bruceb58

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Re: Oil Analysis Volvo Aqumatic-interesting results

You should not be running 10W-40 in your engine or your 270 drive. The recommended oil is 30w.

The measured viscosity level was very low. Possible causes were from thermal cracking of oil molecules, or shear thinning of viscosity improvers... The oil used was Castrol GTX 10w40.
Which is the very reason you never use 10W-40 in a marine engine unless its synthetic.
 
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