Got a 351W Marine long block I am just about ready to stuff into my 23 footer. The Dog House is her name

I need oil that will holt up to near WOT for prolong times as whell as running at just off idle while fighting rough seas. I'm afraid of the auto oils as this 351W has nothing roller on it. And looking thrugh all the oil at Nappa (they are all I got) I could find nothing ya or nay on ZPPD. So I got 15W40 truck oil thinking it would still have the additives that my engine needs. Is this oil going to work or will it cause me problems. Know that I always let my boat get to operating temp before leving the dock. Any input is welcome be it ya or nay.

Arctic

 

Don't know about WOT for extended periods, but the diesel rated oils will have the highest levels of antiwear additives (zinc, phosphorous, etc.) that you can get premixed relatively economically. For extended WOT, it might be necessary to go with something like Royal Purple, Red Line, or Valvoline Racing oil which I believe also have a good additive package and are intended for high rpm applications. These are of course pricier than off the shelf diesel rated oil.

FWIW, I am currently running Rotella 10w-30 in my 351M, rebuilt 1-1/2 years ago.

On edit, there are some oil additives (GM EOS - I've heard going out of production, CD2, Valvoline Synpower) which can be added to your oil to bump up the levels of antiwear agents.

 

Good info Jason. I'll start her and test run her in the shop on the 15W40 truck oil. As she is pretty dry from sitting so long. Than chance to one of the ones you mentioned. I figured that the truck oil May be a little heavy for running 3/4 WOT. Thanks

Arctic

 

Sounds like you could make good use of a synthetic crankcase lube.

On the start-up, why not consider removing the spark plugs & ground the ignition system, disable the fuel pump, squirt some Marvel Oil or the like, into each cylinder, to lube the rings, then crank the engine, to spread the oil in the cylndes, build oil pressure to pre oil the bearings, cam, lifters, ect, then reinstall the plugs, enable the ignition & fuel pump & start er up. Bet she'd appreciate all the attention & not be started up dry!!!!

Just an additional thought or two!!!!

 

Thanks pawpaw. I will do something just like that. No use scoring the cyl up any more than I have to. As she is a new engine. Just been sitting for three years in this salt air.

Thanks bud Tricky

 

15W-40 truck oil is exactly the WRONG thing to be using! "Valvoline Racing Oil" is what you want, or 30 - 50 weight aircraft engine oil. Doesn't MerCruiser sell boat motor oil Given that you warm her up before hammering the throttle, a straight 30 weight should be about perfect. All of those additives (read ash) used in modern oils can lead to preignition causing deposits -that's the rub, and the 15W-40 you selected probably has somewhere around 1% sulfated ash. What is important, however, is that you change oil often and keep the oil temperature under 270* Your boat motor is no different than a drag race engine, so treat it like one and be happy. It will reward you by reliably wanking out full throttle revs.

 

I expected better responses about oils specially from this site but its ok I guess. This is all you need Royal Purple. Buy a quart and try this yourself. put half a quart of water and half a quart of royal purple in a blender and blend it for 5, 10 ,30min what ever you want then shut it off and come back to it in 30 minutes. You will find out it will fully seperate. Now try this with any other oil synthetic or non, and look at your results. Then you will understand for your application and many others royal purple takes the cake. www.royalpurple.com check it out.

 

A 351 is an automotive-based engine, nothing even close to an air-cooled aircraft engine. Exactly how are all of these preignition-causing deposits going to come from? A/C engines are naturally prone to such problems due to the open combustion chamber shape and huge bore sizes (360ci from a short stroke FOUR). His engine is not set up so "loose" that it is going to burn significant amounts of oil. Aviation and true "racing" oils are essentially non-detergent in order to be "ashless". Look at all the trouble with Lycoming cams and lifters. That is why the expensive TCP additive is mandatory many of them.

Jim

 

Since a major by-product of combustion is water, how is RP going to handle it, settle it out at the bottom of the pan, right at the pickup screen? Oils like Delo 400, due to a robust additive package, can easily absorb and safely suspend a large amount of contaminants.

Jim

 

Now I am really confused. I'll test and tune her on the 15W40. But what than? I'll drain er and put in what evever ya all think is best. Please let me know. I plan on living on her and touring Southeast Alaska and want the best for her. But I have been out of the loop for so long and oil has chanced so much that I am really confused.

Thanks Arctic

 

I have a 1997 Ski Nautique with a 351 "GT-40" motor, with more than 1900 hours on it. I have used Valvoline 40 wt racing oil,(part number 223) and the Motorcraft FL1-A oil filters in it since new. Changed every 50 hours, or at end of season layup.

 

Look I hate to put it this way but go to the web site and check out the specs and the videos if you trust the companies that test this product then trust me you will love it. www.royalpurple.com you can get it in 15-40. It is a very High grade synthetic and it you dont have to worry about all the b/s that you get when talking about the leading compation. if you are out in the middle of nowhere and you run a quart low it blends beutifully with any oil and ontop of that it has molly-b as a base line ingredient the percs go on and on. let me know what you are going to do and if you have any more questions that you might not get on the web site just shoot me an email. I own an auto shop and I am the leading retailer for royal purple in Maine. (maine auto service).

 

Rotella 10w40 is a good oil and should meet the specs for your application.


For Mobile 1 only the 0w40 meets specs for Mercedes gas and Diesel's. This is used in their high performance engines and diesels. It is a synthetic as Royal Purple but I don't know the specs on Royal Purple.

I would consider 0w40 Mobile 1. I run it in my corvette and custom build v8 mercedes engine. Both engines are high $$ engines and put to the test.

Many times I hit the rev limiter on the vet on the track. Never an engine. You must consider however your boat engine will run peak rpm sustained. FAA testing on auto engine for certification (last time I checked) No auto engine passed the 100 hr check and I am sure you want more than 100 hrs on your boat.

Best of luck on your decision.

 

not to doubt your choice but have you ever taken a valve cover off an engine running mobil 1 for more then six months. Its a good oil and has a high shear factor but leaves alot of residue and grime.

 

Amazing,, never saw that on my Corvette or Mercedes. Yup,, I have looked.