Ric232

It's interesting that Volvo Penta recommends straight 30W SYNTHETIC for their engines. Problem is, I can't find straight weight syn oils anywhere, except Redline's non-detergent oils, which are strictly for racing.

wild willy

gettin'bye; i have been pondering the very same thing about GM using synthetic oil on some new motors!! i wish we could get someone from GM to explain this!!! i have tryed to use synthetic oil in a new 502 motor before and i couldn't get the rings to seat!! i drained it and put in straight 40 weight and they finally seated!! bill

h2owarrior

What I find interesting is Mercury recommends a straight weight oil for their high perfomrance engines (or they did with my 454 Mags) but their oil is a multi-vis oil.

I use straight weight oil. 40W Valvoline Racing oil. I sold my boat with the 454's last year, it had over 400 hors and is still going strong according to the new owner.

I think the question of wether or not you use the multi-vis oil is how hard you run the boat. I work for a large deisel engine manufacturer and discussed this issue with one of our oil experts. The response was "with the current technology and advatages of the multi-vis oils, using a straight weight oil limits the performance adavatages the multi's provide in varying temperature condistions". Yes the guy is an engineer.

You stated that the reason for the lower "W"(winter) rating was for starting purposes. I believe this rating is more for flow charateristics and ensuring that all parts of the engine (cams, lifters, etc.) receive lubrication even in low tempuratures than actually cranking the engine over.

Bottom line to the conversation was, if you are oprerating in tempuratures above 60 degress F, use a straight weight oil. Below that you may want to consider the Multi-vis.

Something else he indicated was that for the oil to provide its best lubricating properties, it needs to be above 140 F.

Like I said I use straight weight in my boat, but I use 15W40 in my deisel. Go figure.

GETTINBYE

Wild Willy / Bill

So far I have always used Valvoline products in everything I own and have had great results. Did not use any synthetics until we bought a 2002 Camaro SS. As stated its factory fill was Mobil 1 5 -30. This is what I have used in it so far. Am going to try Rotella 5-40 on the next oil change in the Duramax and see if I can tell any difference from the Rotella 15-40 that I have used so far in it.

As far as the boat goes I have used Valvoline 20-50 both racing and non racing, straight 40 racing, and even straight 50 racing depending on what I was able to get my hands on at that particular time.

I am, for whatever reason, going to try Mobil 1 15-50 full synthetic in it at the next change as well as a different gear lube othger than the Merc. HP. Am curious to see if there will be any noticable differences. Have noticed that some props tend to spin more freely than others when spun by hand. Is there free horsepower to be found out there?

Be Safe,
Mark

wild willy

mark;i have been using straight 40 wt kendall racing this year in the boat just because mercury doesn't recomend synthetic and my motor was still under warranty, but now i am switching to mobil 1 . reason is a engine builder posted here a while back saying that on the dyno he has seen an increase of up to 20 hp using synthetic oil .you and i have been in the performance game for a long time! we both keep searching for that little extra!!! see you next spring!!!!! bill

GETTINBYE

Wild Willy,

My thoughts exactly. 15 - 20 HP equals 1 MPH is generally the accepted equation. Every little bit helps & we can always switch back if there is no gain. Have seen the 10 - 20 HP increase comments as well. Notice that amount in the boat? May be wishfull thinking but worth a try. They have to have oil of some sort.

Be safe,
Mark

And yes we will see you next spring. Damn I have a feeling its going to be a long winter.

KAAMA

The performance and how an oil operates within an engine is certainly important and a 20hp gain is a nice gain if true when using a synthetic based oil. However, I also try to look at it from a endurance/longevity point of view and its affect on parts over time as well.

I guess there's a lot to take into account here. It's trying to weigh out all the pro's and con's of a synthetic vs mineral based oil. I would like to try a synthetic oil, but I don't want it to have a damaging effect on my roller lifters. I change my oil every 10-15 hours and I know with a synthetic it doesn't need to be change out as often as a mineral based oil. What is recommended in oil changes for you guys who are running synthetics?----and how often do you actually change your synthetic oil? If oil has to be changed often within a marine engine no matter if you are using a synthetic or mineral based oil---then what are the advantages of a synthetic based oil? I am sure there may be some advantages----but certainly the cost of a synthetic is NOT one of them. If my engines had flat tappet cams/lifters then perhaps I would be interested in using a synthetic oil----especially with all the idling a marine engine sees.......and I hear that is where a marine engine's lifters are at most risk of wear no matter if they are flat tappet lifters or roller lifters.

Any feedback or ideas?

corey

Dennis,

Its been said in a round-about way here, but the lower viscosity is important not just for cold weather cranking ease, but also to get the oil distributed quickly after the cold engine has started--otherwise, extra wear will occur!

turbo2256

I have to wounder if the roller lifter problem is with the solid roller lifters were the spring pressure is much greater and the lobes are more radical than with the hyd ones.

Keith

Dennis,

Great article and input from all. From personal experience, I've always used straight 40wt in summer, and 30wt for 1st 2 months of season, and your answer sums up what I've been told over the years.

In any case, I think it's just as important to mention at the end of the article, he should change the oil filter and oil both on a regular basis, 40 hours time max if he goes with regular. I have a pair of 454Magnums built in 1990 and they're incredibly clean, no sludge build up. One just finally blew a head gasket and the other still runs like a watch. Approximately 700 trouble free hours on them.

I'm not a racer, have never used any synthetics because I can't justify the additional cost. Prefer to use the regular and change it often to keep it fresh, about $30 of preventive maintenance. Merc and GM spend a whole lot of money in Research and Development than me, so I went with what the manual recommended - straight weights, and found no issue with that.