1984 Ski Supreme 351....oil used?

[jess01999]

Guys. I have used the search function and can't find an exact answer for what oil others use in like engine. I have been using Mobil 5000 10w30 and realized recently I should be using an oil with higher ZDDP. Please recommend an oil I can buy easily at Walmart. I put around 25 hours a summer on the boat. Thanks!

 

[Sunnyinhollister]

If you are looking for a 10W-30 oil try Rotella T5 10W-30. It's inexpensive, has good ZDDP value, and you can get it at Wally world

 

[Donald]

I would run a 15W40. Rotella T.

 

[ddtmoto]

QS Defy 10w40....

 

[bullwinkle]

I run Delvac 1300 15W40 in my 350 Mercruiser, much more shear resistant than a 5W30 or 10W30, with it's CF-2 rating.

 

[Chirs]

Hi guys I'm in a similar boat (84 Supra with PCM SBF 351W) I've been agonizing over the same question, and after exhaustive reading on this site including white papers and data sheets, I arrived at M1 high mileage. Unfortunately it's unavailable in Canada.

Would others agree with this? I like the de sludging and seal conditioners, and the 1100 ppm Zinc and phos, but these motors are operated more like a race motor so perhaps something else would be better? My boat is used exclusively for skiing, so it's at or near WOT a lot.

In my case I don't care if I have to go to a speed shop to get it, I just want the right oil.

 

[jess01999]

Originally Posted By: Chirs
Hi guys I'm in a similar boat (84 Supra with PCM SBF 351W) I've been agonizing over the same question, and after exhaustive reading on this site including white papers and data sheets, I arrived at M1 high mileage. Unfortunately it's unavailable in Canada.

Would others agree with this? I like the de sludging and seal conditioners, and the 1100 ppm Zinc and phos, but these motors are operated more like a race motor so perhaps something else would be better? My boat is used exclusively for skiing, so it's at or near WOT a lot.

In my case I don't care if I have to go to a speed shop to get it, I just want the right oil.



After I wrote this post I looked up Mobil HM and I fill like it may be the best fit for me as well. I am a worry wart and don't stray from the OEM recommended weight oil.

 

[Chirs]

What motor do you have? The PCM manual for my motor specs 10W30 or 10W40 which are both available in the Mobil 1 High Mileage. Now all I need to do is find something just as good in Canada...

 

[jess01999]

Originally Posted By: Chirs
What motor do you have? The PCM manual for my motor specs 10W30 or 10W40 which are both available in the Mobil 1 High Mileage. Now all I need to do is find something just as good in Canada...


My manual advises the same......I have a 351/4 240hp. They also offered a 302/4 and 302/2. We have been having some warm days down here and need to get the oil changed soon. I am going to get the Mobil HM and change it this weekend........good luck on finding your oil.

 

[Bror Jace]

jess01999: "I have been using Mobil 5000 10w30 and realized recently I should be using an oil with higher ZDDP. Please recommend an oil I can buy easily at Walmart. I put around 25 hours a summer on the boat. Thanks!"

As was said before, Rotella T5 10W-30

Chirs: " ... these motors are operated more like a race motor ... my boat is used exclusively for skiing, so it's at or near WOT a lot. In my case I don't care if I have to go to a speed shop to get it, I just want the right oil. The PCM manual for my motor specs 10W-30 or 10W-40 ... "

Since your duty is definitely on the heavy side, I'd skip any of the XW-30 oils and opt for a 40 weight. I hate to sound like a broken record, but I'd still opt for a 15W40 HDEO for your application. Good add-pack for a high-moisture environment, high fuel contamination, and plenty of ZDDP for sustained high RPM operation. Pick one: Rotella, Chevron Delo, Pennzoil Long-Life, etc ...

Want the ultimate 15W-40? Go for Schaeffer's 15W-40:

http://www.schaefferoil.com/cmss_files/attachmentlibrary/TD Sheets/700.pdf

 

[ledslinger]

Originally Posted By: Chirs
Hi guys I'm in a similar boat (84 Supra with PCM SBF 351W) I've been agonizing over the same question, and after exhaustive reading on this site including white papers and data sheets, I arrived at M1 high mileage. Unfortunately it's unavailable in Canada.

Would others agree with this? I like the de sludging and seal conditioners, and the 1100 ppm Zinc and phos, but these motors are operated more like a race motor so perhaps something else would be better? My boat is used exclusively for skiing, so it's at or near WOT a lot.

In my case I don't care if I have to go to a speed shop to get it, I just want the right oil.


You must either be a barefoot competitor or ski slalom course with short course entries, or are an over 125' jumper if you run at WOT that much. I competed in three event up to 32 off slalom and didn't use WOT very often, even with 250 HP carbed small blocks.

The easy answer for all inboard ski boats is HDEO, any brand including Super Tech. My Nautique I bought new will see its 30th season this year, I have more exotic oils on the shelf but run HDEOs because I know they will make it last as long as it can. HDEOs are perfect for most marine inboards.

 

[Chirs]

I guess I over stated a bit, I'm a 15 off 30 MPH skier, but I did say at or near WOT. The deep water start is always WOT and then back down for the pass. If it's just my wife driving and me skiing, it is a way down from WOT, but when there's 5 people in the boat it does take a bit more throttle to ski. Still, compared to how a similar motor would be operating in vehicle, would you not say this is closer to race than street? This is an honest question, I'm not trying to argue, just figure out what's correct. I did consider HDEO and that would certainly open up a bit more selection for me being in Canada.

Looks like HDEO gets 2 votes for good reasons.

Thanks guys, there are others on the Supra forum that are debating this so I'll cross post your advice.

 

[DuckRyder]

My GT40 was rated HP at 4800 (or 4600 perhaps) I believe the lower rated engines may have been 4400. Stock it would pull almost exactly the rated RPM.

Cruise RPM was higher than the average V8 car.

I think M1 HM would be a good choice.

 

[jess01999]

Originally Posted By: DuckRyder
My GT40 was rated HP at 4800 (or 4600 perhaps) I believe the lower rated engines may have been 4400. Stock it would pull almost exactly the rated RPM.

Cruise RPM was higher than the average V8 car.

I think M1 HM would be a good choice.




Most of my use is between 2500 and 3000 rpm(I baby it).......I have ran Mobil 5000 in it for years with no issues.....just thought I would try to give it something with a little more zinc. I currently have no leaks so I am lucky on seal condition thus far.