What is the high end for allowable Bravo Drive lube temperature during WOT runs? I am using Redline Shock Proof Gear Lube.

ttt

what are some of the best prices you guys have seen for Mobil1 V-Twin 20w-50? I found it a Auto-Barn online for $9.99/qt. free shipping over $50.00 I love this stuff.

About $10.50 - $10.60 / qt at O'Rielly Auto Parts Stores.

Does anyone have a VOA on the Merc 25w/40 Syn blend oil?
My local Merc dealer does not use it. He uses Chevron Delo 15w40 for everything. I just want the very best for my 7.4mpi ski boat.

Attached is supposedly a Mercruiser Service Bulletin from 1986 on acceptable oil temperatures in Mercruiser engines. Anyone know the history of this bulletin?

Yes it is a 1986 mercruiser SB. back then everything ran 140 degree t-stat and as a by product of combustion comes condensation so if you are using too big of an oil cooler or adding another one then most likely the oil will not burn off that condensation because you are not allowing the oil to get hot enough. Oil and water mix can happen with too cold of an oil operating temp.

One more thing cold oil does not flow very well or as fast as heated oil. One reason why some forms of race motors pre-heat their oil before start up. Best advice for a motor that sits for any lenth of time is use a pre-luber before start ups. Canton racing has one also masterlube.com has one and so does Amsoil but that would not top the list. As for the 1986 Mercruiser SB thats really some of the jist on it as stated above.

Rage, these temps are very good and the info Merc is suppling is also correct.

With a full group IV or V they can handle temps in excess of 300 F as a normal course of business.

That being said, the Service Bulleitin is on the money.

Ken

OK, then the only reason to worry about keeping full group IV or V oils at any temperature lower than ~300F+ is to keep the oil pressure at acceptable levels. In other words the engine may self destruck if the oil pressure gets too low do to elevated oil temperature but these oils will be fine. Got it. Thanks.

Rage, the viscosity gets to low because of the elevated temps, hence the pressure will drop. Remember all oils thin with heat.


With the thinner viscosity (due to high heat or fuel dilution) the oil film can't support the load of the application.

With thinner viscosity oils tighter bearing tolerences and higher pressures will solve the problem of "falling" thru the fluid flim.

Ken