What motor oil do you use?

[Needafunboat]

I'm sure there has to be another thread on this, but I spent a while searching and couldn't find anything. So if someone wants to point me in the right direction, that's cool.

If not - let me know what you run. Being new to I/O's, I'm debating running good old Mobil 1 - they don't make a marine grade. Or running something like Amsoil marine 10W40 full synth. Merc makes a non-synth (maybe a blend?), but I'd like to run full synth. My boat will rarely be in the water more than a few days so I don't think moisture is a huge concern for me, but I'm not sure.

Sure I realize that under normal conditions any good motor oil will work. But I'd guess those (very few for me) longer high speed runs might stress things and synth may help. I always run mobil 1 in my old air cooled 911 for that reason.

Thanks for any info!

 

[mkhammer]

you can not compare a car engine to your boat engine, Mobil 1 is not formulated for marine use. most synthetic oils become unstable in marine use. The first time you run your boat it will be exposed to moisture and start breaking down. synthetic has no anti corrosion agents in it. Marine engines piston tolerances are set up looser than a car engine. A boat run subtained high rpm they burn more oil. It gets expensive carrying around and adding synthetic oil to your boat engine that is not really even protecting your engine and more than likely you won't find it at your marina.

I use Valvoline 30 wt racing oil in all my high performance engines and change it alot, Or Castrol gtx is good( not syntec) All my service jobs are filled with Shell rotella, great oil formulated for marine inboard engines and good for high performance too.

There is marine synthetic oil but you won't find it on the shelf at pep boys or any other auto parts store. I service Volvo penta and they call for a synthetic oil but it is a marine grade very expensive and I have to order it.
You can put synthetic gear lube in your drive, Sierra high performance synthetic blend, Quicksilver synthetic of Torco. I would recommend it in your drive it sees no moisture inside.

So I would advise against it, once you put synthetic in you can't go back or add regular oil to top it off.

 

[Gimme Fuel]

To break in my motor I am going to use Valvoline Racing 20-50W. After that, I am not sure what I am going to. Along with the synthetic debate, synthetic oils are hard on roller cam motors because of the lower spring pressures required, and the increased slipperyness of the oil, the roller lifters tend to slide and develop flat spots instead of rolling. I believe that Amsoil has the only synthetic oil out right now to combat this. Generally, a higher spring pressure will solve this problem too. Just food for thought.

 

[Old Navy]

The real issue these days is the amount of zinc in the oil (ZDDP). If you have a flat tappet cam you NEED this additive to protect it. The oil manufacturers took it out a few years ago, as it somehow reduced emissions on cars. There has not been a production car with a flat tappet cam in quite sometime, so the ZDDP was not needed in automotive applications. Whatever oil you choose to use, either synthetic or not, make sure it has the additives needed by your engine. I have used Mobil 1 V-Twin in my boat for quite a while and have had no problems. My engine has loose clearances so the 20w-50 works well and it has a lot of zinc in it. You can buy ZDDP additive at most any parts store now.

 

[Gimme Fuel]

The Valvoline Racing oils still contain the zinc...hence the "Racing" nomenclature. And that zinc is needed for new rings to properly seat and break in.

 

[mkhammer]

I do not use a multi grade oil in my boats Climate has a lot to do with it, I boat in 100 deg. weather most the time and the engine oil can breakdown to the lowest WT and you loose the protection you need. On the other hand if it is cooler your engine will run cooler and your oil will stay at the thicker viscosity and is harder on you oil pump and circulation, May not hurt your mota but it is proven to rob HP and can cause premature oil pump failure over time.
50 wt is some thick stuff to push through your engine until it warms up. it could say warmed up on you water temp it doesn't mean your oil has thinned yet.

15/40 w is the common multigrade formulated for a stock marine engine that calls out the use of a multigrade by the manufacturer. And you can't find it in a auto parts store. Most those engines don't turn over 4500 rpm.

In high performance applications consistancy is the best policy as far as I'm concerned, I know whats going through my engine at all times.

 

[Needafunboat]

Thanks guys.

That all makes sense, especially about corrosion inhibitors. Anyone know if a stock 454 mag (1995) has flat tappets? I read about the zinc thing and I never really knew the rub with it.

I'll probably use a good grade of marine oil since I don't think my motor is really a high performance motor. May spring for a case of amsoil marine oil.

Thanks for the info!

 

[Big Red]

15/50 full synthetic Mobile 1 a full synthetic maintains better oil pressure after hard runs in a boat

 

[justincase]

Royal purple

 

[Big Red]

This was a debate on another site so lets here from people that have real Horsepower. Here are comments from other High performance boaters



1. same oil as last year,literally,not one oil change yet.
mobil1 15-50 synthetic

2.50W Valvoline VR1.

3.Amsoil 20/50

4.Amsoil Series 200020-50

5.mobil 1 15w50

6.Mobil 1 15w50

7.whole lot of years running Valvoline 20-50 racing and I'm not changing.

8.I was always running the 20-50 I only switched to straight 50 when I started running these blower motors

9.25-50 Penzoil Full Race

10.Mobil 1 20-50 V Twin. best stuff on earth

11.never change mine, just add new when I rebuild my JC motor every 10 hours

12.Mobil delvac super 1300 15w40


I think we can fight this till we are blue in the face

 

[mkhammer]

I am a high performance engine builder for 25 years,I know guys that race and use synthetic oil and change it after every run, But using Mobil one is not for every day marine use and 20 hr. oil changes, So 12 hardcore boaters swear by using synthetic oil or 20/50 doesn't tell what's right.
Mercury racing advises against using Synthetic oils in their blue engines. Oil viscosity is determined by climate. 25/40 works in all climate,

I blueprint all the oil pumps that I put into my engines. I will not run a multi grade especially 20/50. for the reason that it starts out thick. I don't think you now what hp it takes to put that through your oil pump. Example: water is thicker than molasses meaning thinner oil can go through the pump gears easier than thicker oil. I see guys run heavier oil in blower engine and they run hotter and they think they need heavier oil because their oil is breaking down so fast. When in a lot of cases the heavier oil is cauing the heat. They are defeating their purpose.
They wash out their torlorance and have to run it because they see a drop in oil pressure if they don't. I have seen this from my own past experiance not where I read someone said.
It can also cause timing fluctuations It's been proven on a dyno. The cam turns your distributor your ditributor turns you oil pump, heavier oil will have a binding affect on your oil pump the restriction will rob HP and also rob more by
stressing the oil pump shaft and distributor gear will have back lash bind. it can cause timming flucuations. For these reasons I use 30 wt Vavoline racing in my engines and change my oil frequently. Straight 40 works good too
So I can't reccomend oils that have seen failures in Marine applications that are mentioned and oh ya they do in time if not marine formulated. I use in customers boats what is recommended by the manufacturer. none call out to use 20/50 or mobil one period. I use in my performance engines what works for me and what I feel I can stand behind.
So there is no argument here I'm just saying what I know.

I use Mobil one in my Mustang.

 

[lcboater]

I had a new zt240 with a 7.4 mpi merc engine. From day one it used a lot of oil. After complaining to dealers and merc about it,they all said it was"normal". I was telling a friend of mine,an engine builder at Peformance Marine Systems, about my problem and he told me to try Mobile 1 10w-30. After i started using it my oil consumption went to zero. The 10w-30 is the same as the merc oil . I have used the Mobile 1 ever since with no problems.I always cut my filters open to check for metal and never see any,the inside of the engine is as clean as new, and my procharged 496h.o gets run hard.

 

[JW]

Interesting some comments against Mobil 1 10W-30. A few years ago a boating magazine followed and reported on an extensive test of oils, with a eye on corrosion.

One oil that stood out was Mobil 1 10W-30 synthetic because it protected against moisture/corrosion BETTER than most of the oils, whether marine or car or traditional or synthetic. It also protected against wear better than most. This was under lab conditions, not seat of the pants guess work. I've used this oil in my Honda 15 since it was broken in, with zero oil burning and zero loss of compression for 11 years now. Uses have ranged from light weight boat/6200 rpm use to pontoon boat use. ZERO issues.

Back to the point, I always ran the factory Merc 25W-40 oil in my boats. Your engine isn't a race engine, why not use what Merc recommends? You can find it for a decent price if you look around. The oil is a blend of 25W and 40W, not a multi-vis car oil.

 

[Big Red]

 

[fireguy]

Anybody have any experience with Amsoil's Formula Four Stroke oil?

 

[yellowfiero88]

I always use SAE30 in my supercharged fiero ad SAE40 in all other motors I have. I have never had a problem with oil pressure dropping after hard runs nor failure due to oil. I do not like the multi weight oils as oil pressure drops as the oil gets hot. Only thing I use it in is my duramax and I use rotella in that.

 

[wca_tim]

Thanks for the interesting info and comments especially from experience (Hammer, Red, others).

I'm running mobile one 15w50 right now on the advice of the guy who built the engine in my boat. His word was that was what they saw the best results with on tear down of similarly built engines and what they recommended for synthetic. I add zddp for the flat tappet cam, but would not if I could have found the vtwin in stock somewhere the last time I changed the oil. it's built with looser tolerances as hammer mentioned, but it does not use very much oil at all... and the expense of adding a bit is not that much of a consideration compared to what changing the 8+ quarts it holds costs... Before that I ran rotella t, again on his advice. They have a heck of a rep for building bullet proof engines for the circle track and offshore community and everything they've told me - even the things that were contrary to what I read as "common knowledge" in other places - has been dead on.

I've also run redline and am running redline (shockproof) in my outdrive with a noticable difference. I wouldn't hesitate to run amsoil series 2000 either and am about to swap one of my cars over to amsoil

 

[mkhammer]

I guess people run what they are use to and what works for them, I have been told by some of my oil reps that Mobil one does not have the anti corrosion agents needed for marine use. Merc precision 25-40 is not the same and would be my pick if I were to run synthetic. Like JW said every body is not changing oil in race engines, And I can see that guys run what they know. But me as a shop If a boat owner blows his boat up because I put in oil that was not recommend for his application I may be held liable.

What I use in my personal engines and what I recommend I my high performance engines is what has been working for me.
Not all engine are created equal Machining varies, I find some production engines are looser than other,

 

[Big Red]

Thanks for the interesting info and comments especially from experience (Hammer, Red, others).

I'm running mobile one 15w50 right now on the advice of the guy who built the engine in my boat. His word was that was what they saw the best results with on tear down of similarly built engines and what they recommended for synthetic. I add zddp for the flat tappet cam,

Is zddp for the cam lobes during break in, if it is comp cams says it only needs to be used for 20 minutes. The additive does not need to be put back in after break in

 

[ndaniels]

The 24 has only run mobil 1 15-50 since the motor was built and the 21 has only used 20-50 Castrol Syntec blend in it since built. The 21 only has 40hrs on it, so time will tell.