switching to synthetic motor oil?

Is it ok to switch to synthetic motor oil in our V-8's? I run it in my diesel truck with good results. I am willing to spend a little extra money on the boat and wondering if this is a good thing to do.

Any experiences?

On the newer motors PCM does not recommend it.
My Excalibur runs what is basically Diesel Oil 15w-40.

Check out the PCM site here - PCM Website

Not to mention you already have over 1000 hours on that engine running the dyno. Leave it.

M3Fan wrote: Here's another use for that money: Sign up for the reunion.

I've heard that its ok for new motors but that it can be a harsh transition for a motor with several miles/hours.

Help me out here, I switched to synthetic oil when I had about 300 HRS on the 88. I did this because I was running around 100 Hrs a season and just wanted to skip a mid season oil change. Have 1334 Hrs now and still running synthetic, should I switch back to Dyno oil ???? Mostly I was using Amsoil Marine oil 15W-40 and is rated for light or heavy duty diesel marine applications???

used royal purple only in all my diesels great stuff. Run it in my commercial mower also.

I wouldn't switch over to synthetic on an older boat because it may cause leaking or other problems, but it may be worth considering on a newer one. I switched to Amsoil on an '03 with 250 hours. It's got about 350 now. I run it in my trucks and go 10-12k between changes. I'm not convinced on the benefit for a boat yet though, as I still change the oil at 50 hours.

I use Mobil 1 in EVERYTHING I own since about '85. I use it in my pressure washer and lawn mower even. I ran four vehicles over 200K miles and never had a mechanical problem of any kind or used oil. My boat started running M1 at the 450HR mark (when I bought it). Now has 1200 and when I changed the heads and intake, the lifter valley looked brand new (that was at 800HR's). I change the oil filter every 2K miles on my vehicles and then top off the amount the filter holds, then do a complete oil change at the 8K miles mark (per most new engine warranty requirements). The boat I change the filter every 10-15 hours and then a complete change at the end of the season. I've never had a leak, or started using any oil because of a switch to synthetic. As far as I'm concerned, you could never pay me enough to use dyno oil again. If you live in a place where you have a vehicle exposed to extreme cold (North) or extreme hot (South or under a boats engine cover) you cannot go wrong with synthetic. If you're worried about cost, changing the filter the way I do becomes a break even proposition over dyno if you keep a vehicle for 50K miles. That's assuming that you do a complete dyno oil change every 2K and the synthetic oil filter every 2K with a complete change at 8K. I figured it out once apon a time. As far as newer vehicles not running synthetic, I can't imagine that any engine would not run with less friction and be better protected over dyno. Engine manfacturers don't recommend synthetic because people who aren't in-the-know try to run synthetic way longer than normal WITHOUT changing the filter. There isn't an engine warranty in existance that will not cover a failure because you used synthetic oil. They won't cover it if there is evidence that the oil was not changed when it should be (dyno or synthetic). Sorry for length but I could go on for hours about this.

TRBenj, I completely agree with your mind set, Rotella and a FL1A Motorcraft,chang it as the book say's and live a long and prosperous life Luke Skywalker.......boat dr

TRBenj, too many schools and warranty issues involved in denied claims. Run the stuff that came on the unit from the factory.
Mercruiser will not pay on a claim that involves synthetic,engine or drive train.To me that's a strong statement ,don't use the stuff and ask us to foot the bill on parts or labor............boat dr

Lorenr,I would not tell that story to my best friend,the only thing I can say is I hope you did not put used oil in a Correct Craft.
And you go on to say you sprurged on a 15.00 dollar oil change,then ruined a tranny from a loose prop shaft,Dad had a saying that applies perfectly in this case.
Penny wise and dollar foolish..........

The additives are not there only for the cam break-in , the lifters need the heavy metals for a long life,Run cheap oil and filters, don't tighten any bolts and God forbid ,Do Not Install A New Impeller Every Season...............boat dr

boat dr,

I know that my post seems odd, but I really have been doing this for a long time. Read my post carefully. I put that stuff in there for a reason.

I built drag racing engines and transmissions for a long time before I got smart and bought a ski boat. I like the rest of you, started out by using the best parts and maintenance programs possible. However, I wasn't as fast as other guys so I wondered what it was that made their motors better. What I found was "forget all the romance BS and pay attention to the basics".

I've seen guys run their used oil through cheese cloth before putting it back in the motor.

You could easily run synthetic engine oil for 10,000 miles, filter it properly and put back in the motor. No kidding.

Probably the hardest thing for fresh water cooled engines is condensate in the oil pan.(motor does not get hot enough to boil off the moisture) That might be the only reason to change the oil.

Mercruiser will not pay on a claim that involves synthetic,engine or drive train.To me that's a strong statement ,don't use the stuff and ask us to foot the bill on parts or labor............boat dr
Maintain the motor at regular intervals{50hrs.}10/30 or 20/50, ain't nuttin special about that,just don't expect them to pay if you deviate.

As for warranty claims,if they insist that you use a particular product to keep from voiding your warranty...federal law says they must provide it to you free of charge.

when do you get to a point in a motors life when you decide i better run synthetic?
Ive never got to that point yet and probably never will unless its designed for use with synthetic oil. along with transmissions, synthetics are great for mechanical transmissions but in many cases not for hydraulic transmissions in fact in some of the higher performance transmissions we build we recomended type F because it has an additive that increases co-efficience of friction which means the pack wont break loose as it would with normal ATF and with the introduction of synthetics you have more of a chance to allow the clutches to slip. Ive never heard anyone say the engine failed cause i changed the oil when i was suppose to. it's the engines that fail when your on 5 season intervals on boats and every 50,000 on a car