Synthetic oil ?

[Suprapots99]

Is there any objections other than cost to using a full synthetic?

[wotan2525]

What year boat and what size engine?

[KarolinaKid]

Is there any objections other than cost to using a full synthetic?

I've run full synthetic in the engine and tranny for years.

[supraaddict]

I was wondering about this also. I have heard Royal Purple is good to use in the 5.7L.

[autobahnracing]

I have been running Amsoil for many years in my pcm 350, not a single problem or complaint.

[michael hunter]

I have run Mobil 1 15w50 in my 89 since break in has 770 hours now no problems.

[docdrs]

Your not supposed to use synthetic till after 100 hours. fwiw

[autobahnracing]

Your not supposed to use synthetic till after 100 hours. fwiw

+100

Put it in a new race engine once and never did get the rings to seat.

[TitanTn]

I used synthetic on almost everything I own. I struggle on the decision to put it in the boat though, because I change it every season and the amount of use is so low. It seems like a waste to run synthetic for 5 months and only every other weekend.

But no, I don't think there are any objections. After the recommended break-in, you're not going to hurt anything. I just wonder if you get any benefit out of it.

[michael hunter]

I remember the 35 hour years when I lived up north . Here in Georgia the season is so long and I am so close to the lake I average 250-300 hours a year. That's 5-6 oil changes a year. Even at that I still use the synthetic I feel the extra protection is worth the extra cost. Note the older flat lifter engines require ZDDP additive . Mobile 1 15w50 has the additives for older engines some of their other weights do not.

[csuggs]

I remember the 35 hour years when I lived up north . Here in Georgia the season is so long and I am so close to the lake I average 250-300 hours a year. That's 5-6 oil changes a year. Even at that I still use the synthetic I feel the extra protection is worth the extra cost. Note the older flat lifter engines require ZDDP additive . Mobile 1 15w50 has the additives for older engines some of their other weights do not.

Ditto what Mike said. In my opinion Mobil-1 is like cheap insurance . . . .

[cadunkle]

Synthetic is fine, and if your rings are sealing well (and oil stays visibly clean) you can run extended change intervals. Change the filter around 50 hrs and top off, then change oil at 100 hrs. Synthetic oil does not break down as quickly as dino oil. For a flat tappet cam you generally want phos/zinc levels over 1000 ppm. Stock pressure valve springs and 800 ppm is fine, I would be concerned with less though. More aggressive ramp rates on the cam and higher spring pressures and 1000-1200.

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf
http://www.amsoil.lube-direct.com/2011/07/high-zinc-oil-amsoil/

Basically for a stock marine cam with low lift, slow ramp rates, and low spring pressures you can run whatever oil you want and have no worries. If you upgrade the cam and valve springs, be more picky on what oil you run.

[TitanTn]

It seems auto mechanics never retire, they just change their oil 5-6 times a year. Holy Moly!

Wouldn't it be cool to use your boat enough to ask yourself "Do I need that 6th oil change or not?"

[KarolinaKid]

Wouldn't it be cool to use your boat enough to ask yourself "Do I need that 6th oil change or not?"

Yes, that would be freaking awesome!

[Jetlink]

I am averaging a single oil change a year on both the boat and the tow pig... Next year it might be two oil changes on the boat while still one on the tow pig. Only running synthetic in two vehicles though, not the boat.