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Discussion Starter · #1 ·
At risk of starting the Synthetic vs. Non argument, what kind of oil do you use?

The boat I just bought has been running Wolfs Head sae 40 in Merc efi 350's. I used to run Merc 25w40 semi syn in my last boat with a Merc 350. I had been questioning whether the added expense of the syn is worth it.

I have been trying to do research on oils to use. There are many opinions out there about using Chevron Delo 15w40, Shell Rotella 15w40, or Mobil Delvac 15w40 which are all supposed to be great heavy duty oils. However they are not FC-W rated which is the marine designation. From my reading the FC-W rating is based mainly on additive levels that are important for winter storage.

I just hate to spend extra money on Merc oil when there may be an oil out there that is just as good or better for less money. Brand new engine I would probably run Mobil 1 or Amsoil full syn, however I don't know how I feel about changing to this in an older engine that has been running dino oil for so long.

Right now I am probably leaning toward the merc 25w40 non-synthetic.
 

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I am an admitted synthetic bigot. I use Mobil 1 in everything, including my Crusaders. I use 15-50. I was impressed after I tore down a couple tubrocharged engines after 150,000 miles which had used synthetics most of their lives and became a follower. I am sure other synthetics are comparable to Mobil's, but I haven't read or heard anything that has changed my mind over the last ~25 years or so.

I'd be interested to hear anything that comes up in your research.
 

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I went back and forth with this dilemma earlier this year. Right or wrong, I decided to continue with frequent oil changes of conventual oil. Maybe if one oil change a season would do me, I'd go there other way.
 

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Rotella T 15W-40. It's rated for gas engines as well as diesel. I did the same thing when my warranty expired. I ended up on the phone with a chemical engineer at Shell. After quite a lengthy conversation (learned a ton about oil!!), he basically made the recommendation for either his product, OR the Delo!!! I was surprised he was that honest...

They both have high levels of ZDDP (Zinc Dialkyl-Dithio-Phosphate), which is a huge anti-wear compound, typically not found in your gasoline engine oils in these high amounts. Most gas oils have gone to nearly nothing of ZDDP in the name of lower emissions, and to save the catalyst.

If you were to stay with conventional oil, I would use either Rotella, or the Delo.

Of course if you go syn, that's a whole other deal.

I don't see great benefits of syn in our boats. We don't see the longevity benefits that syn oil provides because at the end of the season, we drain it and refill it. However, there are those that will swear by it, and for them, good for you. But I have yet to see definitive evidence re the benefit of using a syn oil in a pleasure boat in our climate.

We use Mobil 1 in all of our auto race engines here, but that is apples and oranges....
 

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Valvoline Racing VR1 Straight weight 40 No real reason except for the additive package it contains.

The #1 selling racing motor oil. High zinc provides race-level protection for any vehicle.

High zinc/phosphorus provides extreme wear protection, including flat tappet applications Needed from info I was given and all motor oils do not have..
Additional friction modfiers to help deliver maximum horsepower
Enhanced anti-foam system protects engine during extreme stress
Compatible with gasoline or alcohol fuels
Available through leading auto parts retailers

Tire Liquid Fluid Bottle Automotive tire
 

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QUOTE(NoShow @ Sep 28 2009, 09:38 AM) <{POST_SNAPBACK}>Valvoline Racing VR1 Straight weight 40 No real reason except for the additive package it contains.

The #1 selling racing motor oil. High zinc provides race-level protection for any vehicle.

High zinc/phosphorus provides extreme wear protection, including flat tappet applications Needed from info I was given and all motor oils do not have..
Additional friction modfiers to help deliver maximum horsepower
Enhanced anti-foam system protects engine during extreme stress
Compatible with gasoline or alcohol fuels
Available through leading auto parts retailers

View attachment 67109
Same here, but I run straight 30w because that is what the manual calls for. Excellent oil IMHO.
 

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I just run the quicksilver stuff.

If I didn't, I would either run something cheap and straight-weight (no multi-weight oils) or M1 v-twin 20w50.

You do not want to run a typical automotive multi-weight oil. Only the best oils are acceptable in multi-weight formulations. Typical multi-weight oils are formulated at the lower viscosity, then viscosity enhancers are added that reduce the amount the oil thins out as it heats up. This is bad in any engine that is run at high loads for an extended period of time, as the viscosity enhancers will shear out and your oil will revert back to the lower viscosity. ie your 10w-30 will become a 10w.

There are some quality oils out there where multi-weight properties are achieved without viscosity enhancers. All the multi-weight means is that they meet cold pourability of the w number (5w, 10w, 15w, 20w, or 25w are all "winter" ratings and basically indicate cold pourability) and the viscosity requirements of the other viscosity number. That's basically two viscosity tests, one at low temp and one at high temp. Cheap oils use viscosity enhancers to achieve this, good oils don't necessarily need those.

Quicksilver 25w40 falls into the good oil category. It is actually pretty damn good non-synthetic oil. M1 v-twin 20w-50 and the amsoil motorcycle oil equivalent also fall into this category. M1 automotive oils vary in quality based on cap color, but in most cases are good enough for most marine applications. I don't know about VR1 - I would generally avoid "racing" oil simply because they often use less additives because they are generally changed more frequently (ie: every race) and aren't required to deal with corrosion issues related to sitting in a humid bilge all year long. This may or may not be the case with VR1.

You can use a straight-weight oil (SAE 40, etc.) and you don't have to worry about this. Even the less expensive straight-weight oils should be fine for a marine application.

My recommendation? Just stick with the quicksilver. It's readily available, recommended by the manufacturer, not much more expensive than good automotive oil, and it's good stuff.

If you want to read more (a LOT more) go to www.offshoreonly.com and search for a thread called "marine lubrication". It's long.
 

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QUOTE(Convincor @ Sep 29 2009, 06:27 PM) <{POST_SNAPBACK}>Pennzoil. Auto Zone. 10W-40. When you got twins that Mobil1 will break you.

Switch to straight SAE 40. Your engines will thank you.

After running some hours, send some of your oil into blackstone for analysis and see what they say. I bet it's closer to a 10w than an SAE 40.
 

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Discussion Starter · #13 ·
When I do my oil changes at layup this year I am going to send in an oil analysis on both of the engines. Its a good way to see how the inside of your engine is holding up.

Right now they have Wolfs Head sae 40 in them.
 

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QUOTE(sleeper @ Sep 30 2009, 02:06 PM) <{POST_SNAPBACK}>QUOTE(Convincor @ Sep 29 2009, 06:27 PM) <{POST_SNAPBACK}>Pennzoil. Auto Zone. 10W-40. When you got twins that Mobil1 will break you.

Switch to straight SAE 40. Your engines will thank you.

After running some hours, send some of your oil into blackstone for analysis and see what they say. I bet it's closer to a 10w than an SAE 40.


I did the year before, but the stores don't carry SAE40 in cases or large jugs. Making it more expensive when you buy it by the quart. That is why I went with the 10W.
 

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QUOTE(SKUZA @ Sep 30 2009, 12:00 PM) <{POST_SNAPBACK}>Always used Penzoil straight 30w. Is that a little thin for summer use?

Same here, better for cold starts and the same for high temps as all the W ones
 

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Im Captain Overkill, and thats OK with me...

Always have used Amsoil 10w/30 heavy duty diesel rated oil in my boats.... from the 3.0l in my 1st boat (the Larson) to my 5.7GS in my late 99 Four Winns.

Also use Amsoil in all of my gearboxes (axles on my truck, outdrives, etc.)
 

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QUOTE(Convincor @ Sep 30 2009, 04:08 PM) <{POST_SNAPBACK}>QUOTE(sleeper @ Sep 30 2009, 02:06 PM) <{POST_SNAPBACK}>QUOTE(Convincor @ Sep 29 2009, 06:27 PM) <{POST_SNAPBACK}>Pennzoil. Auto Zone. 10W-40. When you got twins that Mobil1 will break you.

Switch to straight SAE 40. Your engines will thank you.

After running some hours, send some of your oil into blackstone for analysis and see what they say. I bet it's closer to a 10w than an SAE 40.


I did the year before, but the stores don't carry SAE40 in cases or large jugs. Making it more expensive when you buy it by the quart. That is why I went with the 10W.


Keep your eye open at Autozone, they offer cases of Castrol SAE 40 and Bosch oil filter deals all the time.
 
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