8.1L V8 - oil black after 20hrs of use. Normal ?

[oil pan 4]

Wish I knew. The water temp is rock solid at 160F but the boat doesn't have any oil temp gauge.

A big block in a car or truck running 160f is probably going to run about 180f oil. On a boat that runs wide open throttle for extended time probably gets the oil a little hotter. That that 180 to 200f range is usually 30 weight oil territory. But you have to for sure know the oil temp.

 

[ripcord]

A big block in a car or truck running 160f is probably going to run about 180f oil. On a boat that runs wide open throttle for extended time probably gets the oil a little hotter. That that 180 to 200f range is usually 30 weight oil territory. But you have to for sure know the oil temp.

You also have the fact that there is next to no air flow around the block and sump in a boat hull so that tends to increase the oil sump temps.

 

[alarmguy]

Oil temperatures on inboard boat engine run much hotter than that of the water temperature.
We have to get out of the mind set that a boat has 4 wheels and easily gliding over a road surface like an automobile.

Marine engines endure an incredible amount of stress on its internal components, something a car engine never experiences. Take the wheels off the car and try to have the engine move the car would be a closer analogy.
A marine engine is pushing a GIANT log through water, the stresses on the engine and resulting combustion chamber and bearing temperatures is what increases marine oil temperatures to the limit in some cases.

 

[hemitom]

Oil temperatures on inboard boat engine run much hotter than that of the water temperature.
We have to get out of the mind set that a boat has 4 wheels and easily gliding over a road surface like an automobile.

Marine engines endure an incredible amount of stress on its internal components, something a car engine never experiences. Take the wheels off the car and try to have the engine move the car would be a closer analogy.
A marine engine is pushing a GIANT log through water, the stresses on the engine and resulting combustion chamber and bearing temperatures is what increases marine oil temperatures to the limit in some cases.

Couldn’t have said it better.
I Look at it this way my car cruise’s at 1500 rpm at 70 .
My boat cruise’s at 3800 rpm at 40 it takes way more abuse than a car.

 

[SubieRubyRoo]

It has been quite sometime since i used any VR1, but i recall it starting out dark (not black) like maple syrup.

Plus, if the latest LSJ infomercial is to be believed, VR1 oxidizes very quickly. That will turn an oil dark especially when it’s under heavy load.

 

[bullwinkle]

Most boats only run a 160F stat. Combined with an unlimited cooling water supply, I wouldn’t bet on oil temps getting as high as an on road truck (closed loop cooling system excepted). 15W40 HDEO seems like the ideal oil for a non-emission boat engine, plenty thick enough to take it.

 

[mr_boring]

Side note, nice boat. Bet she scoots.

 

[oil pan 4]

Isn't there a pic thread on here of engine oil dipstick pics with miles and/or hours.

 

[Donald]

I think you need to be using a Marine Oil and not a Racing Oil. Contact Pablo here, he is an Amsoil Dealer, he could recommend an oil for you.

I could be wrong, but I do not think if someone is using a Racing Oil that the Motor should not be idled a lot. There are also some different characteristics between Racing Oil and Marine Oil.

A straight weight 40 should be fine. Many boat owners run a gas & diesel 15W40 like Shell Rotella T6. Please boats are mostly run in warm weather.

Many boat engines are similar or identical to gas engines in cars or trucks but are often run at a constant RPM for several hours.

 

[alarmguy]

Most boats only run a 160F stat. Combined with an unlimited cooling water supply, I wouldn’t bet on oil temps getting as high as an on road truck (closed loop cooling system excepted). 15W40 HDEO seems like the ideal oil for a non-emission boat engine, plenty thick enough to take it.

There is no correlation of water temperature and oil temperature in a marine engine. Meaning water temperature of 160 degrees does not translate into anything near an oil temperature of 160 degrees. The temperature of the oil must be taken. Taken in reverse it would be like taking the oil temperature of a marine engine to know how hot the water temperature is.
Here is a thread on how to get a close approximation of oil temperature if you don't have a gauge.

Engine Temperature and Oil Temperature Range?

What is normal oil temperature on a Mercruiser 3.0L engine? I decided to check the temperature with an IR thermometer gun on my engine and found the oil filter was at 220 degrees after running it hard for about 20 minutes. The block low down ranged anywhere from 150-240 degrees. The riser was...

www.marineengine.com

 

[B6_Dolphin]

This is a situation where a Mityvac extraction pump would come in really handy. It would allow you to do mid season oil changes without taking the boat out of the water.

Amazon.com

I had a similar thought. I use a 10L capacity Bavarian Autosport Oil Extractor for changing-out the oil on both the 2.9L and 3.0L V6 engines in my RS5 and SQ5 Sportback, respectively:

https://www.ecstuning.com/b-bav-aut...p-stick-tube-bavarian-autosport/b8800001~bav/

As for whether the OP should change-out the oil in his marine engine, "If there is any doubt, change-it out".

Oh, and get a UOA for piece of mind.

 

[ringmaster]

Plus, if the latest LSJ infomercial is to be believed, VR1 oxidizes very quickly. That will turn an oil dark especially when it’s under heavy load.

I will look into the viability of doing a mid-season oil extraction / change while the boat is in the water.

If this doesn't work out and I need to run ~30hrs without changing the oil, is there something better than the VR1 40wt?

 

[SubieRubyRoo]

I will look into the viability of doing a mid-season oil extraction / change while the boat is in the water.

If this doesn't work out and I need to run ~30hrs without changing the oil, is there something better than the VR1 40wt?

What are the specific recommendations in the OM for this engine? That will help narrow choices down. Also, what’s the sump capacity and your intended budget for oil purchases? What has your past oil change frequency been, and how many hours total use yearly?

 

[ringmaster]

The OM calls for SAE 40, CG-SJ4 oil and the sump capacity is 8qt w/filter.

Oil cost isn't a consideration; this thing drinks close to 10gph of fuel while surfing which makes oil changes look cheap.

I would like to run the oil for 30-40hrs over an eight week period.

 

[BrendanC]

The OM calls for SAE 40, CG-SJ4 oil and the sump capacity is 8qt w/filter.

Oil cost isn't a consideration; this thing drinks close to 10gph of fuel while surfing which makes oil changes look cheap.

I would like to run the oil for 30-40hrs over an eight week period.

try some synthetic 15w-40 HDEO. i think it is better suited than “race” oil.

 

[wpod]

Bost engines are under quite a load.

 

[PontiacHO]

Can’t offer any comfort on the oil change however my assumption is this is a roller cam engine. VR-1 is great oil for a race engine (flat tappets) but has limited detergents. As mentioned previously a quality heavy duty 15w40 is fine or the tried and true (preferred) Quicksilver 25w40 marine oil.

 

[ringmaster]

This Quicksilver? I haven’t heard of the brand before now.

25W-40 Synthetic Marine Engine Oil | Quicksilver

 

[PontiacHO]

Yes. Conventional or Synthetic. Created for Mercury 4 stroke engines but a fine product. Some folks will argue this but it’s only my opinion…it has more anti foaming agents along with the stuff that negates the effects of the additional moisture that marine engines are subjected to. Marine engines may have been based on automotive engines however they are subjected to much higher RPMs for a longer amount of time. An oil that has more anti foaming agents is definitely a plus….

 

[brandon9715]

Not to be an Amsoil shill, but if it were me I would run their dedicated marine oil. A dedicated oil is ideal in a high-load situation like boating imo.