Hydrocruiser

It's been a few years since I started the first such thread and thought I would weigh in again with an update.

Rumor is that Mercury pulled 25w-40 Full Synthetic off production..excuse if I am wrong.

So if you want full synthetic oil for offshore powerboats (just means with the right additive package) I suggest any of the following...and certainly not limited to this brief list:

M-1 20W-50 V-Twin (Proven by many members here!)
Amsoil Z-Rod 20W-50
Amsoil Dominator Racing 20W-50
Royal Purple XPR 20W-50
25W-40 Mercury Semi Syn
Volvo Syn I think it's 15W-40

The goal is to filter and flow without restriction and we see it all...from mild to wild.

When in doubt go with manufacturer's suggestions especially during warranty.


I know many use 30wt dino
25W-40 Merc ol both syn blend and dino
Various 20W-50 Dino's

Be Very careful not to run a modern day "automobile oil" that has much lower level of the additives than offshore boats need or expect greater than normal wear,

Consider 25 hr changes

Take good care!

Pismo10

Thank you very much for your efforts and knowledge over the years..

class6

How and why is Royal Purple In your list? does it just meet spec's or you tested it to be good? I have lost Race engines from RP! I will never use that again. This is only my opinion, not looking for trouble. Just trying to save someone a lot of money

Hydrocruiser

Out of all the Synthetic Oils listed Royal Purple is known to shear more than others. Plenty of users don't like it for that reason. It's mainly used because it has a ton of moly and gives a few more HP during a race..then drain and refill..

I have heard that of the Syn's listed M-1 V-Twin is one of the one's to beat.

High Performance engines upon head maintenance service at 50 hrs show remarkable results..you can eat off the heads..that clean and nice looking.

SB

iTrader: (1)

Valvoline™ VR1 Racing Oil's high zinc provides race-level protection for high performance engines on the race track and is compatible with passenger vehicles. Additional product benefits include:
•High zinc/phosphorus for anti-wear protection, including push-rod and flat tappet applications
•Formulated to increase horsepower
•Enhanced anti-foam system protects engine during extreme stress
•Recommended for engines burning gasoline and full or partial alcohol fuels

SkiDoc

iTrader: (4)

Hydro. What do you think a good bet for a hard working nautique 6 liter 409hp with catalytic converters. Heard may not want to use high ZDDP with the cats. True or False? What do you think of Merc.'s recommendation of Kendall Racing 20 w 50 for my Merc. 700 SCI's?

BUP

iTrader: (9)

You can not use very high zinc and phos for cat engines. Mercruiser and Volvo both have gone back and forth with this hopefully for a happy medium - Merc had a 20 w -40 syn oil that they changed because it did not have enough zinc and phos for anti wear protection but was great for NOT poisoning the Cat. Volvo also changed their straight syn 30 w to a 10 w - 40.

The marine cat engines need a good balance here for good anti wear protection but not too much to pollute the cat sub strake. I have more marine CAT training thru 4 major marine engines manu's that most techs all put together .

You can not go wrong for NON CAT engines using the Driven products or the newest VR 1 Racing Valvoline that came out a year or 2 ago.

BUP

iTrader: (9)

Forget to say non approved cat motor oil voids your whole warranty point blank. All marine Cat engines have thru the manu and of course EPA mandated - 3 years or 480 hours which ever comes up first. Even spark plugs are warranted thru this period timeframe.

myturn

I have used Mobil 1 V-twin 20w-50 on my 496 HO's.
I just send the oil in for analysis, and the results
showed virtually no wear after 400 hours.
I changed the oil every 25 to 40 hours.

BenPerfected

We have stayed with the Mobil1 V-Twin and Fram HP6 or the Wix Racing 51060R oil filter. After about 8 seasons wailing on the boat, the engines have just been shipped to be freshened. Won't surprise me if the internals look like new.