Best motor oil?????

[TBroccoli]

What is the best motor oil to use in my 454 magnum?? Previous owner left a quart of Mobli1 5w 30 tri synthetic in the boat. Should I use what I believe he was using?

[RedDog]

now you've opened the proverbial can of worms :rolleyes: Religion, politics, and collegiate football are safer subjects. This topic is over the top - right up there with windshields and foaming of replacement gas tanks...

Valvoline Racing straight 40W.

Most folks don't recommend a multi-viscosity oil in a boat

[gold-n-rod]

Most folks don't recommend a multi-viscosity oil in a boat

Hmmmm, isn't the Mercruiser recommended oil a 25-40 multi-grade oil?

I'm running Royal Purple 15-40 in my 7.4, but I'm thinking about going to the Mobil 1 15-50.

another Randy

[roadtrip se]

Reggie Fountain gave me that recomendation and I have had pretty good luck over the years, so I'll stick to it.

Anything fancier is just a waste of money, if you are changing it out every 20-25 hours.

Now lets move on to religion or restoration technique, I've just about had it with politics!

Todd
"Michigan, home of the political attack ad, I'll show you a swing state!"

[RedDog]

Here we go ...

Straight quote from my Mercruiser Operation and Maintenance Manual (for Bravo and Blackhawk Models):

"In those areas where recommended* straight weight oil is not available, a multiviscosity 20W-40 or, as a second but less preferrable choice, 20W-50 may be used."

*The occupanying diagram shows for above 50 degrees F, SAE 40W is the recommendation.

This is followed by a note:

"IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than 20W-40 or 20W-50), low quality oils or oils which contain solid additives, are specifically not recommended."

[MOP]

More poop on the pile! My machine shop guy is adamant about not using synthetics in roller motors its to slick, he says the rollers will skid and develop flat spots. Now for more controversy he says he really like Rotella it has better bearing support and is way more high detergent than regular auto oil. He says many of his really hyper motor guys run it with very good luck, It is in my new mouse motor that he just put back together.

Phil

[Rootsy]

More poop on the pile! My machine shop guy is adamant about not using synthetics in roller motors its to slick, he says the rollers will skid and develop flat spots. Now for more controversy he says he really like Rotella it has better bearing support and is way more high detergent than regular auto oil. He says many of his really hyper motor guys run it with very good luck, It is in my new mouse motor that he just put back together.

Phil

ummm phil i need to disagree with you on the synthetic not being suitable for a roller motor... i am pretty confident that postulate is total balogna. Heck Griz might even post if he reads this one... if everything is mechanically sound and you are running proper spring pressure and don't float it you should have ZERO issues...

for god's sake GM ships brand new LS1 motors with Mobil 1 AND A WARRANTY and i sure as heck don't see many nuked roller cam stories floating around... unless well someone put the wrong lifter in the motor to begin with :smash:

as for me i run Valvoline Racing 30 in my mouse with a melling HV / HP pump. Personally i don't put enough hours on between oil changes to really benefit from synthetic oil. the valvoline doesn't even have much of a chance of breaking down before i drain her... 30 is the same base stock as the 40 without the viscosity modifiers, etc... ZERO issues, ZERO metal and 60 PSI hot above idle... 25 @ idle hot - 50 cold... bearings look like brand spankin new...

If i put more hours on my motor, in a hotter climate than i currently do at elevated and extended rpm without an oil cooler i might step up to a higher viscosity... but for now it works for me...

Just me half a cent worth...

JR

[Dr. Dan]

:cool!: I am running Valvoline Racing Straight 40 W, mostly cause the Kendall was not available...but I agree with Todd and Poodle who have given me guidance in my boats metamorphosis....with the HP 500 EFI!

I change mine about every 20 hours, depending on the intensity of the Events I run in....if it's anticipated to be a challenging weekend....I change it prior.....if it's a mellow run like Sarasota and mostly show I still change it...I like to keep it clean....

I am of the opinion that overall regular maintenance and awareness of all your Boats operational systems...is the best medicine. I budget $3 to $5K per year....prior to my repower!
I kinda screwed the Pooch on the "Preventative Maintenance Budget" this year....good news is I can start a new with all of my new parts...new parts are sooooo much more easy to keep shiny too! :spongebob

Doc of the Bay

[MOP]

It looks like Griz agrees with my guy about the issue of rollers skidding with synthetic oil. With stock stuff it seems to be fine but with high spring pressures it can be a problem that I do not want to face to many $$$ in the engine. Check his post in the thread below.

http://www.donzi.net/forums/showthread.php?t=36875

[Lenny]

I bought 5 quarts of 40W for the first oil change in my "new boat to me". Anywhooo, I just came up from the boat "shop" and there are 2 left. Seems the other three are now German Shepherd "play toys, and emtpy", all over the driveway, and they are being stored beside his recently acquired plastic tubes of Silicone for counter top caulking.


..I will keep an eye on his breasts... :rolleyes:

[Donzigo]

................a 40wt oil. I used Pennzoil last change; but, any good brand will do.

[smokediver]

there is a good article in trailer boat mag. this month . tested was many oils in a yamaha 4 stroke outboard . Looks like pennzoil is the best for the buck . they broke down each oil chemically and explained what was for what . good article .

[fasttrucker]

Heavy/racing Castrol or valvoline straight 40 weight.DO NOT USE SYNTHETICS :splat: unless you do not like your motor and want to see your donzi sitting.

[TBroccoli]

I thought straight 40 weights were used in big diesels. Thats what dad uses in his Detroits. Why does Quick Silver stock 4 Cycle 25w - 40 and recommend it in the Mercruiser engines?

[gold-n-rod]

Like some of the others, I'm still confused, especially about those having a problem with multis. I agree with TBrocoli about the 25-40 QS oil. Why do they sell and spec it? And what's with the synthetic haters?

Is there a synthetic straight weight oil made? I seem to recall that Redline offers straight weight synthetics, but for racing only. What does that mean? No detergents?

Also, what effect does water temp play in all of these discussions. I can see where 40 wt oil would be good when one in running at high speed in warmer water which is generating the highest and most stressful running conditions. But what about cruising speeds in 60 degree water. Wouldn't a multi be a good use here? And what about startup and slow idle through the channel on the way to the big lake?

As you can see, I have way more questions than I have answers. :banghead:

another Randy

[RedDog]

... about the 25-40 QS oil. ...

I'm not an expert - I just read the owners manual. See post # 5 above.

[MOP]

And what's with the synthetic haters?

I love syn oils its in everything I own, just not going to use it in my full roller setup. There are many stories about the roller lifters skidding and developing flat spots and ruining the cam shafts. It may be fine once the engine has decent time on it not sure. Since this post went up I have been asking a few racers I know they have mixed feeling mostly against, thats enough for me not to use it. I have a bunch of bucks in the mouse motor and will not risk it. Below one article that may be of interest from GM!

http://www.gmpartsdepot.com/572startupinst.html

[gold-n-rod]

Below one article that may be of interest from GM!

http://www.gmpartsdepot.com/572startupinst.html

From the article: "13. Do not use synthetic oil for break-in. It would only be suitable to use synthetic motor oil after the second recommended oil change and mileage accumulation."

Break in and normal operation are 2 different things, IIRC. GM never says (in this article) don't use synthetics for non-breakin operation.

another Randy, not trying to start something, just trying to understand.

[Cuda]

In the my 454/420's in the Formula, I run whatever high quality 40wt is on sale, and keep it clean. I'm running the same in the Minx. In my F20, I am experimenting with Rotella myself, it's just that I don't think I've put ten hours on the eninge in the last 3 years.

Over on Oso, there's a guy that has all the breakdowns for the different engine oils and he has come to the conclusion that Mobil V Twin made for motorcycles has the best overall measurable numbers. Take it for what it's worth. I have never used synthetics, not because I'm against them, but because I'm a tight ass. I know I'm a whole lot likelier to change out a $10 oil than I am a $50 oil, so I'll do it more often. Just one of my many charachter flaws. :)

[RedDog]

... I'm a whole lot likelier to change out a $10 oil than I am a $50 oil, so I'll do it more often. Just one of my many charachter flaws. :)

Excellent point!