oil for a marine 351w?

[MurkyAsparagus]

I may be picking up an older Mastercraft boat w/ the 351w engine.

It has flat tappet cams, requiring an high amount of ZDDP.

I’ve kept a mental note of all the oils available locally that also have high ZDDP. Here’s the list, let me know if you have any other ideas! I’m interested to see what everyone thinks of the Supertech, it has a pretty stout additive package for the price, and has even shown some good UOAs in semis on this forum. Thanks again!

1. Valvoline VR1 - 20w50
2. Castrol GTX - 20w50
3. M1 - 15w50
4. Rotella T4/T5/T6 - 15w40
5. Supertech HDEO Full Synthetic - 15w40
6. Mobil Delvac Extreme - 15w40

Here’s the diesel VOA database for those who may be interested.

Thread 'VOA Diesel Oil Database'

Dec 5, 2022

I stumbled across @himemsys thread that combined a bunch of PCMO VOA in one spreadsheet (You can find that sheet linked below). I figured it was such a great idea that I decided to also put one together but with HDEO (Diesel Oil).

https://bobistheoilguy.com/forums/threads/voa-database.360118/#post-6244004

I created a line that adds up the Additive Package in the oil. This is displayed with the most additives towards the top, to the least additives at the bottom. This line is labeled "Add Pack". It is not listed in alphabetical order. On the bottom left side of the sheet...

• fantastic
• Replies: 44
• Forum: Virgin Oil Analysis - PCMO/HDEO

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[thastinger]

I would probably go with an actual Marine 25-40 for that as I suspect you won't be lightly cruising a mastercraft, if not then M1 15-50 would be decent and Royal Purple has an HPS line of oils that have high ZDDP levels (maybe their 10-40 HPS would be good). My larger concern would be the gimbal bearing and outdrive oil.

 

[Chris142]

Is that engine any different than one in a truck? The trucks are not eating cams with lowered zddp oils.

 

[Rand]

Is that engine any different than one in a truck? The trucks are not eating cams with lowered zddp oils.

there is no 15hp crusing down the highway with boat engines.. they are sucking down gas and producing hundreds of hp for long periods.

However being its not a racing engine not sure how much "elevated" zddp is needed.. rather than a normal high 1000ppm~~ level.

a decent 15w40 fleet oil or marine 25w40 would likely be my pick.. with no farther background info available.

 

[Zap1967]

I’ve logged thousands and thousands of hours on 351 flat tappet marine engines using rotella 15-40 T4.

If you’re going to run wide open a lot like barefoot type of service I’d probably go T6 for the higher temperature tolerance (large mains in the 351 heat up oil even though they don’t make much power). Fords tend to have pretty tight bearing tolerances so the 20-50 isn’t normally necessary.

Basically anything I ski with now is a big block Chevy but I do run one barefoot rig that’s a stock 240 horse 351. It will get the at speed oil pressure a bit low for my taste so it’s got normal VR1 20-50 in it. It basically runs wide open 4600 rpms any time we use it.

351s are much more tolerant of ZDDP levels vs the big block Chevy.

 

[JavierH19]

Any of those will be fine. If you want a solid well priced oil this is what I use in my gas engines. The 10w-30 is 3.5 hths while the 15w-40 is 4.2. Both are sufficient viscosity wise and the PDS for both claim 1270 zinc and 1150 phos.

I'd use the 15w-40 if it was mine but the 30 is good to use too though the noack on the 30 is 13 while the 40 is a better 10 but I'd never complain with the 10w-30 in my sumps. Order at least $45 for free shipping which is what I do. Lowes has other Mag 1 oils like gear and hydraulic oil.

https://www.lowes.com/pd/MAG-1-Mag-1-10W30-CK4-H-D-Diesel-Oil-2-5-Gal/5001933103
https://mag1.com/products/73/pds/

https://www.lowes.com/pd/MAG-1-Mag-1-15W40-CK4-H-D-Diesel-Oil-2-5-Gal/5001932875
https://mag1.com/products/72/pds/

 

[Chris142]

About what year is the engine? I remember that Ford went to roller cams in the v8's around 1986

 

[SC Maintenance]

Is that engine any different than one in a truck? The trucks are not eating cams with lowered zddp oils.

They run backwards comparatively, and hence has a different cam. Other than that, not much. I agree that they were not known to have cam problems like some other flat tappets, and in this case they didn't make enough power to really hurt themselves. If you get further up the HP curve the weak link was the rod bearings IIRC.

Having said that no CAT - no reason not to run higher ZDDP if you like.

About what year is the engine? I remember that Ford went to roller cams in the v8's around 1986

I think the rollers came out with the TB fuel injection, and I don't think those ever went into marine. I could easily be wrong - marine stuff is very poorly documented.

 

[Rand]

Any of those will be fine. If you want a solid well priced oil this is what I use in my gas engines. The 10w-30 is 3.5 hths while the 15w-40 is 4.2. Both are sufficient viscosity wise and the PDS for both claim 1270 zinc and 1150 phos.

I'd use the 15w-40 if it was mine but the 30 is good to use too though the noack on the 30 is 13 while the 40 is a better 10 but I'd never complain with the 10w-30 in my sumps. Order at least $45 for free shipping which is what I do. Lowes has other Mag 1 oils like gear and hydraulic oil.

https://www.lowes.com/pd/MAG-1-Mag-1-10W30-CK4-H-D-Diesel-Oil-2-5-Gal/5001933103
https://mag1.com/products/73/pds/

https://www.lowes.com/pd/MAG-1-Mag-1-15W40-CK4-H-D-Diesel-Oil-2-5-Gal/5001932875
https://mag1.com/products/72/pds/

while the price is attractive.. being dirt cheap and conventional how fast do they shear down?

 

[JavierH19]

while the price is attractive.. being dirt cheap and conventional how fast do they shear down?

That I don't know for sure but they do have some diesel approvals specifically volvo vds 4.5 and volvo dictates that 3.4 3.9 is the after shear hths. 3.4 is for 30 grades and 3.9 for 40 grade so with 3.5 on the 10w-30 it can only go down by .1 and with 4.2 on the 15w-40 asking for 3.9 shouldn't be too much since it says it's approved for it on the pds.

The mag 1 15w-40 is made by warren and is likely the exact same as supertech 15w-40 which did have high aw additives in a voa I saw. The 351w ran regular pcmo 5/10w-30 and that was much worse than a modern conventional 10w-30 pcmo and hdeo made today so I imagine it'll be ok at minimum since it's better than what the engine was made to take.

 

[OVERKILL]

We have the GT40 version in our '95 Supra, I've been running Delvac 1 5W-40 in it with a Fleetguard filter.

 

[Zap1967]

About what year is the engine? I remember that Ford went to roller cams in the v8's around 1986

Ford Windsor engines never received roller lifters in marine flavor. Last production was 02 for Pleasurecraft as the GT-40 still using flat tappet (just like the hi po 351 in the first gen Lightning).

 

[PontiacHO]

I had the 351 FI engine in my last pleasure boat. The dealer serviced it while under warranty using Union 76 10w40 racing oil. High zinc. Carry on with VR1.

 

[eljefino]

Marine cams are radically different than automotive ones. Auto you want a nice even torque curve from 1500 to 4k RPM. Marine you want the tq curve to keep going up and up until redline. Not surprised they didn't bother switching to a roller.

 

[MurkyAsparagus]

I would probably go with an actual Marine 25-40 for that as I suspect you won't be lightly cruising a mastercraft, if not then M1 15-50 would be decent and Royal Purple has an HPS line of oils that have high ZDDP levels (maybe their 10-40 HPS would be good). My larger concern would be the gimbal bearing and outdrive oil.

Any recommendations for a marine grade oil?

From what I’ve read, most run VR1 racing oil or the like.

 

[MurkyAsparagus]

Is that engine any different than one in a truck? The trucks are not eating cams with lowered zddp oils.

It’s different in a few different ways. I’m not as familiar with it as I am other engines. I’m more familiar with the more modern engines.

 

[MurkyAsparagus]

I’ve logged thousands and thousands of hours on 351 flat tappet marine engines using rotella 15-40 T4.

If you’re going to run wide open a lot like barefoot type of service I’d probably go T6 for the higher temperature tolerance (large mains in the 351 heat up oil even though they don’t make much power). Fords tend to have pretty tight bearing tolerances so the 20-50 isn’t normally necessary.

Basically anything I ski with now is a big block Chevy but I do run one barefoot rig that’s a stock 240 horse 351. It will get the at speed oil pressure a bit low for my taste so it’s got normal VR1 20-50 in it. It basically runs wide open 4600 rpms any time we use it.

351s are much more tolerant of ZDDP levels vs the big block Chevy.

Thanks for the info!

There’s going to be a good bit of barefooting that’s going to be happening .

 

[MurkyAsparagus]

About what year is the engine? I remember that Ford went to roller cams in the v8's around 1986

1990.

 

[OVERKILL]

It’s different in a few different ways. I’m not as familiar with it as I am other engines. I’m more familiar with the more modern engines.

It's mostly just the cam that's different from the Lightning truck engine. It's a 351W block with GT40 heads and the GT40 intake (at least that's what we have, there are three or four different versions).

Windsors are not picky on oil. We've owned a few marine Windsors, had a Mercruiser 888 (188HP 302) sterndrive on a Glastron that had thousands of hours on it, engine outlived the boat and it wasn't fed anything more exotic than GTX or VWB 10W-30.

Not sure what sort of duty cycle racing oil is designed for, but we know HDEO's are geared toward engines that spend lots of time at high load and moderate RPM, which has some parallels with marine use and several of the marine OEM's recommend HDEO's I assume for this reason.

Historically, the reason for the narrow spread on the marine lubricants is to keep VII content low, as they don't really need a Winter grade that excels below freezing. But, with higher quality base oils, you can get something like the HPL No VII 10W-40 that's completely VII-free.

 

[thastinger]

Any recommendations for a marine grade oil?

From what I’ve read, most run VR1 racing oil or the like.

VR1 or Castrol 20-50 "classic car high zinc" would both be fine. If you are looking for something with ZDDP levels over 1000PPM then you are going to be looking for oils that DONT meet API SP standards because 800PPM is the limit there.
Even the marine oils have cut waaay back on ZDDP levels because new boats have cats now.
Royal Purple makes a line of oils called HPS, that has high levels of ZDDP. I've ran that in my 4.3 Volvo Wellcraft for years with good results. They have 5-30, 10-40 and 20-50 in the HPS line. You can find UOA and VOA of that oil on here with a search.
Otherwise, you would be into motorcycle oils like Mobil 1 4T or backup generator oils like Kohler 10-30 (a very stout oil with VOA on here).