Trojan Boat Forum

I recently purchased a 1979 F-32. It has the chrysler 318's. The generator is a 6500 watt Onan. The previous owner used Valvoline 10w-40 but I have been told that it would be good to go to a straight 30w. Just wondering what everyones thoughts were before I do my spring maintenance.
Thanks

Multi viscosity oil basically is better because it protects the engine when it is cold and also when it is hot.

The operator manual calls for straight 30 weight but that was before we had all the options for oil we have today.

If you operate in the northeast, 30 weight might be really too heavy when it gets cold and make it hard to start.

If you operate in the south, then 30 weight might be too thin when it gets really hot.

I prefer a good quality Amsoil 10w 30 or 10w 40. It costs more but lasts longer and is better oil that you don't have to change as much.

In my Crusaders, I have been using a good 15-40.

You can also do your own little research here too.

http://www.bobistheoilguy.com/

I have used 15W-40 in my last 3 boats and of course my current boat .
I also use in one of my cars as its the only oil that keeps it quiet and keeps it from using oil . ( 200k mile plus chevy cav. )

What do you guys think about synthetics? Besides price.....
I havent switched the boat yet but it did wonders for my truck after it hit 150k stopped oil consumption , burning and quieted down a few lifters ticking for the next 40k before I sold it. and yes it was the same weight.

I also remember when I raced motorcycles, the only thing at the track was synthetic oil.

I use 25W-50 Amsoil Synthetic in my 350 and in the generator. This stuff flows well when cold and has a high shear rating.

Synthetic by all means. It has better properties for wear and lasts longer. Costs a little more but well worth it. 15W 40 should work fine in most areas. I've seen engines that ran like crap and burned oil turn right around after a couple of oil changes and quiet down and stop burning oil when using synthetics over natual petrol oils.