Hydrocruiser

Got a question as to what is unique about some of the popular synthetic oils?

-Just compare some virgin oil samples and you can see for yourself!

LILGUY

Would Mbl1 VT 20/50 be appropriate for a stock Merc 6.2..Running 40 wt Pennzoil since change.60 hrs on engine.

Hydrocruiser

I think you should just ask.."can I switch to a synthetic oil"...answer is yes.

Then decide on the one best for you with the information here.


I am trying not to make recommendations anymore...just provide the factual info. My positions have not changed just taking a bit more of a back seat...

This would be a good question for Vandy..aka Craig as he is our Mobil expert and can get info for us that is not available elsewhere. I would be interested in knowing his feelings and experience with V-twin.

vandy021

Hydros recommendation is fine for the 20w50. He can recommend any oil that he would like. For years thousands of people have used the 15w50 and have had no problems in a marine application. The new EP is basically a marketing gimmic if you want the absolute truth. The oil has been reformulated, but I still have 25,000 mile warranty cards in my office from the original Mobil 1 days. They are guaranteeing the new EP for 15K. Kinda weird?? The first time I have ever heard about people using 20w50 in a marine application was on this forum. ExxonMobil has a full on-slate of Marine lubricants that they stand by but the only problem they are for crosshead diesels and trunk piston. I do know though that Mercury will not void warranty for switching over, or at least that's what they told me in person a few weeks ago. Most Sterling engines come out of the shop with Mobil 1 and Neil from Cig swearers by it. We have used it for over 15 years on our boats and we have done religious oil sampling thru Mobil and independently and the oil has stood up time and time again. We have even run engines with conventional in one and the syn in another. You will not be disappointed. Any synthetic will work. If you like Klotz, or Amsoil, or Royal Purple. A lot of it is personal preference and what gives you a fuzzy feeling. If you are not running a dry sump motor or blown engine you will be fine. Let the engine get five hours on it's inital and then you can move to synthetics. If you look at Mobil's website they say nothing about Marine Lubricants. It's all PVL and Aviation. Millions have used it, it's worked 99% of the time and the choice is up to you. Short answer w/o all the numbers, synthetics are better than conventional, they have no impurities.

Hydrocruiser

Cig and Sterling using 15W-50 or 20W-50?

I know it's Mobil-1 for sure at Sterling...they like the way it mixes with gas and protects I was told in the event gas finds it's way in...

vandy021

15w50. And yes gas does get in with the 1050's. We had bad fuel dilution. With those motors, you had to change the oil every 10 hrs. No matter what syn. you used. Every analysis came back with heavy fuel. Even if the motors were leaned out.

Hydrocruiser

True of many blower engines...some oils don't mix with gas ...M-1 is a good choice for a blower engine.

tomcat

Stupid question, but are these engines with bad fuel dilution supercharged, and are they using excess fuel as a cooling/detonation control?

bob

Hydro-why do you feel 50-60 wt oil is recommended for race applications? I could Cut/paste some oil company statements regarding this but I am looking for a non biased opinion.

vandy021

You need to call Mike at Sterling on that. We just had viscosity come back out of whack from ExxonMobil with the Signum Oil Analysis. It was showing very heavy fuel dilution. Even with turning things back, leaning it out, going hotter on the spark plugs. They were 1050 Sterlings. Sterlings engines ran very cold and never showed any water or oil pressure. We called him, the new boat owner called him and he said that's how they run, maybe that has something to do with it??? The engines were just ran over by his crew with the new owner and seem to be fine. I am not sure. I can look for the results sometime. They are not confidential since we owned the boat.