minxguy

Yes you are correct, the oil industry now uses cSt as the scale to measure viscosity of oil. That does not mean you cannot use SUS as a measurement also. Blackstone Labs does. It is easier to understand viscosity in measurement that are easy to comprehend, Saybolt Universal Seconds (SUS) are as you know seconds in time, right off a stopwatch. I think the average person can relate to this easier than trying to explain centistokes. We "collectively" understand MPH better/easier than say Knots or Kilometers per hour.
The SAE has min and max ratings at 0F of -17.8C for "W" rated lubes. They may not be used in the lab, but these numbers can give a customer a "feel" for the change in viscosity that a lube stock goes through from cold (0F) to the upper test temp of 210F. For example (using SUS) a 20w50 at zero degrees will take between 12,000-48,000 seconds (200-800 minutes) for 60ml (approx 2oz) to pass thru the viscosimeter. That same oil when tested at 210F will pass thru between 85-110 seconds. (1.5-2 minutes). Oil thins with heat.
I also agree with your and Hydro's statement of too thick an oil causing wear. I would not want to start my engine with an SAE 40 at 15F. In the time that it would take to get oil to the top end,you my expereince som engine wear, and over enough of these starts in cool weather, your engine is worn out.
I stated "use an oil you are comfortable with" IMO you can't beat a 15w-50 or a 20w 50 vicsosity is our application. Oil viscosity is your first line of defense against wear. Too thin and parts wear out. Ever wonder why they change the engine after qualifying at a cup race? They run super thin oils and they know that the engine would not last the duration of the race. I am strictly talking viscosity, additives are another story. Ken

Hydrocruiser

Sterling Engines uses 15W-50 EP M-1 in 1,000+HP offshore engines that go in race boats.

Trust me...15W-50 synthetic oil is perfect. I would not say the same about conventional oil as they can shear a lot more.


Even Merc's 25W-40 blend is too thick for colder weather...ask them as I did.

M-1 15W-50 synthetic "pumps" like a 10W-40 conventional oil would.

Another synthetic "plus".

o2man98

Looks like Mobil 1 may now be making the 15w-50 EP with a majority of Grp III basestock.

http://theoildrop.server101.com/foru...gonew=1#UNREAD

Wobble

That sucks, They did say that the 10w40 and 20w50 vtwin motorcycle oils are still full synthetic. I switched from the 15w50 to vtwin when they reformulated for emissions over a year ago, didn't realize they had cut the synthetic content also.

sleeper_dave

Can you guys take a look at these results and tell me what you think?

Start with the oil. 26 hrs on oil. 1 quart added @ 5 hrs on oil, filter changed and 1.25 quarts added @ 22 hrs on oil. Rebuilt 502 w/ 130 hrs on it, stock, carb'd. Merc 25w40.



On to the gear lube. This is where i'd really like some input. I ran this gear lube all season. Merc HP gear lube. Any reason I can't do the same next year? I'd say a typical summer is 70-100 hrs for me, this year i only got 69 hrs in.

I took this sample without draining the drive. I took it from the top fill port with the little pump blackstone sells.

Hydrocruiser

Are double digit copper and iron levels acceptable?

sleeper_dave

I got the dyson analysis too, on the oil.

here's what he said

Hydrocruiser

The copper levels indicate significant upper valve train wear and the iron indicates fairly significant cylinder wear and additionally lots of wear in the lower bearings....I am most concerned about the wear taking place in the crankshaft bearings. Could lead to early failure.

Lots of fuel is getting into the oil...fix this fast!

A fact is that Mobil-1 (or any good synthetic oil) 15W-50EP can handle fuel dilution better and prevent this type of wear much better than conventional oil can.

When you check your oil sniff the dipstick for gasoline...if you semll gas change the oil immediately.

I am also wondering if you got a decent job done on your rebuild dude or not?

sleeper_dave

I probably got ****ed on the rebuild. They changed management at the shop almost immediately after I got the boat back. But it's not a high HP build, just a stock rebuild. I have pics of what came out, if this motor pops and it doesn't have the same pistons, crank, and block when I take it apart as the one I dropped off, i'll be suing someone. It shouldn't be too hard for a supposedly reputable race shop (heads up racing) to toss rings and bearings in a big block, and have the crank cut.

I will be running synthetic next year. I will also try to figure out how to adjust the carb. I bet the idle mixture could be backed down a bit. The motor will get plugs and wires in the spring.

Do you have any opinion on the condition of the outdrive gear lube? Should I be changing it more often than I have been? I've been doing it annually.

Hydrocruiser

The gear lube has little if any ZDDP anti-wear additives in it and your iron levels are very high showing significant wear.

Pull the carbs and get them checked out if not rebuilt or replaced. I would compression test the engine FIRST as a bad ring job can lead to fuel contamination as well and if it isn't right go after the rebuilder.

What lube were you running?