ok, so why not synthetic oil in the 500EFI's???

Remember Mercury does not make their own oil they have it blended to their specs. What does Mercury know that Mobil Royal Purple and the others don't know about racing engines.

I don't know but I use the Mercury 20w40 and change it 3 times each season.

I have always run full synthetics... myself and the previous owner always used Mobil 1 15w-50 and got 500 hours on them. When we freshened them up, the motors looked great. Thats reason enough for me.... Now since my rebuilds, I ONLY run Amsoil Dominator Racing oil 15w-50... and I sleep just fine at night. I have 502's with SC's making 6 pounds of boost....
At the end of the day, its cheap insurance.

The one conversation I had with the team at Merc Racing about syn oil was explained to me as they contain too much parafin??? Not sure what that has to do with it - but that's the quote I got....

Parrifin is in a petroleum oil, not synthetic.


See how much Mercury knows about oil.

Ken

has anyone seen premature failure as a result of using synthetic in 500efi? if the rollers on the cam cant spin properly on synthetic, then there would be synthetic users reporting cam failure of some sort. maybe this is a problem at high rpm only?

harley tried to pull the same story on us''dont use synthetics in our engines!!'' now that they sell it,its a different story...we opened hundreds of H-D engines running synthetics,with no evidence of rollers sliding on the cams...just imagine a roller sliding on a cam with 180 pounds of spring on its head...that doesn't happen...everything i own with an engine runs synthetic oil
jack
hdr precision

Minxguy is absolutely right. It's the mineral oil that contains parrifin's not the synthetic. The parrifin's are a "waxy" buildup and sometimes cause a gasket to swell.. The synthetic actually cleans that build up. So, think about a timing chain seal. If it has swollen and of course the crank revolving is causing some sort of wear to the seal. Now shrink that seal back down and you have a leak. But, in my opinion the real reason to use a synthetic is because it is just a better product. Not even talking about who is better! If you could see the molecules in the mineral oil you would find they are not the same size. If you take a one foot square piece of glass and place it on top of 100 rocks of roughly the same size how many rocks do you think it will contact.........10 or 15 (10-15%). Remove the rocks and place 100 man made marble's under the glass. Now it contacts 100%. That is what the synthetic does for you as it is man made. Would you rather have a bearing contacting the crank at 15% of the surface or 100%?

Everytime I read these threads on use of synthetic oils in Mercury Racing engines and those comments about roller lifters not rolling properly over roller camshafts I absolutly CRACK UP and if I am drinking hot coffee or otherwise I usally spit it out laughing my ass off! I am always amazed at the Bullsh*t spread around about the use of synthetics in marine engines! Use the correct weights and types and you will ALWAYS have less wear, less heat and more power using synthetics PERIOD!

Parafin in synthetics - WOW that Merc rep must have been smok'in his crack pipe to hard!

Someone's gonna have to bend my mind real hard to get me to change my experience in this area. You take apart, build and manufacture as many engines as I have and others in the industry who know the benefits of proper synthetic oil use and your gonna be old and gray before you ever convince us otherwise!

Mercury's 25-40w blended premium (Quicksilver) oil is a very good quality oil and will work wondefully in any Mercury engine where its recommended. You should probably buy some Mercury (Brunswick) stock at the same time and maybe you get a little return on that big investment in their promoted-overhyped oils?

Best Regards,
Ray @ Raylar