minxguy

I know Spectro Platinum is 100% PAO.
Ken

minxguy

Yes you can mix he two. At what ratio? I do not know. I guess I would start by throwing in a qt of 20/50 and the balance 5/30.
I guessing your valves were not floating, your lifters were making noise because they were not pumping up. A 5/30 oil will get to the lifters faster.
Ken

Hydrocruiser

Oil needs to be labeled I believed to include basestock and levels of additives.

Consumers don't know what they are paying for.

...hello Ralph Nader..

Rage

Or a oil rating system that acurately quantifies the performance merits/short comings of the base stock used in the oil being marketed.

minxguy

Rage, just remember that there is a quality level rating in place for finished lubricants.....
it is the API rating on the bottle. The SAE qualitifies viscosity. the API qualifies quality.
Ken

Rage

Ken, I am totally ignorant as to the merit of the API rating and I understand that the SAE viscosity rating is only for new oil? I am thinking of the oil rating short fall, as I perceive it exists from listening to you all, in that the difference in viscosity drop over time/usage of one oil versus another oil is not recognized by the current rating standards. That seems to be one of the main merits of the Group IV base oils versus the Group III and lower oils that I am hearing discussed. Am I wrong here?

Rage

Different subject, lower unit oil change intervals/oil testing. After the first season with the OEM LU oil fill I switched to the Redline Heavy Shockproof Gear Lube. Over many years of boating and using Merc LU gear oils I have become used to the darkening of the oils as they accumulate hours of use. After 80 hours of use the Redline HDSGL looked like new in color "pink". There was only the lightest coating of metal dust on the lower drain plug magnet and even less on the upper. This may have been left over wear debris from the OEM oil and the previous 90 hours of use.

How do I determine when I actually need to change a LUGL like Redline HDSGL? Will a Blackstone oil test provide a definitive indication? What is/are the key items on a Blackstone report to base the need to change decision? The Redline gives me a sense of security that I am using the best there is for the Bravo 1 but it is extremely messy to change.

Engine is a single 496 @~525hp on a 3700# 25ft and duty cycle is mostly cruising with occasional hot runs.

minxguy

API's (American Petroleum Instute) purpose is to set levels of additive performance with technical input from SAE and ASTM. These levels have to do with additives like zinc, detergent, deposit control, oxidation etc.
You are correct in the way you perceive the viscosity issue. The SAE only concerns itself with new oil, not used. Yes, one of the main merits of a Group IV is better viscosity retention over time.
Ken

minxguy

Rage, I would quess that the lack of color change is due to the synthectic gear oil not oxidizing as rapidly as the OEM petroleum. As far a drain interval, run the unit and the drain out X number of ounces (top off with the same oil that is in the lower unit) and ship it off for an analysis. The first thing i would look for is water, (the oil should have gotten milky though) and wear metals. I would doubt that a quality synthetic would fall out of grade that fast, but I think they also do a viscosity report.
Full synthetic gear oils can run in excess of 250,000 miles in over the road trucks. I would think it would hold up for 100 hours.
Personally, I change at the end of every season 25-30 hours.
I use Spectro full synthetic 75w-140 GL-5 and honestly I do not find it very messy to change. It seems to be no more messy than a petroleum 80w-90.
Ken

Rage

Ken, actually I was contemplating running the Redline ShockProof Heavy gear oil multiple seasons if it was retaining like new properties (that I could prove by analysis) and no water contamination.

I would hazard a guess that you have never used the Redline ShockProof Heavy gear lube. It is not like any oil, synthetic or other that I have experienced in that regard. Its nature seems kind of like a fluid RTV silicone caulk.

I will try the sampling and oil test you suggest at the end of next season.