What type of oil?

F

frosh coach

Member
exMember
Joined
May 7, 2007
RO Number
26203
Messages
207
Twin 1994 mercrusier 350/260 hp fwc with about 350 hours. What are others using for oil? Is it time to go synthetic? Does it have to be mercrusier?

Thanks
 
350 hours in 20 years means you will never wear out the motor it will rust away first. If you change it every year, which is a must to get the acids out you are changing it with less than 20 hours of use. Standard oil is fine, synthetic is a waste.
 
Agree on the synthetic, probably not worth the money. I have a 1999 4.3, I had been using standard dino oil (Mercruiser brand), but this year switched to the Mercruiser synthetic blend. I'm at 400hrs.
 
I'm using straight 30wt Rotella Diesel oil. It seems to be popular with owners of older engines with non-roller lifters.
 
I can't remember ever hearing of anyone blowing a motor because of the brand they used.
Lot's of people use straight 30 weight.
I now use the Mercruiser synthetic 25W40 because it's what was recommended to use in my new motors, and it only cost a few bucks more. But I don't think it really matters.
 
Rotella or Delo 15-40 as soon as the engines went out of warranty. Much cheaper than synthetic and readily available at Sams or Costco. Many diesel oils are now carrying dual ratings.
 
I've been using the Mercuiser Synthetic Blend since it first became available. I put about 25 hours a year on my boat now and change it once a year. I use synthetic oil in everything I own because of years of seeing the results of dino sludge in engines of vehicles I've worked on. I have never seen sludge in an engine that runs synthetic.
Rob
 
quote:
Originally posted by Brite Idea

I've been using the Mercuiser Synthetic Blend since it first became available. I put about 25 hours a year on my boat now and change it once a year. I use synthetic oil in everything I own because of years of seeing the results of dino sludge in engines of vehicles I've worked on. I have never seen sludge in an engine that runs synthetic.
Rob

Click to expand...

I doubt you would see sludge on any engine that had its oil changed every 20 hours.
 
quote:
Originally posted by mdoherty

quote:
Originally posted by Brite Idea

I've been using the Mercuiser Synthetic Blend since it first became available. I put about 25 hours a year on my boat now and change it once a year. I use synthetic oil in everything I own because of years of seeing the results of dino sludge in engines of vehicles I've worked on. I have never seen sludge in an engine that runs synthetic.
Rob

Click to expand...

I doubt you would see sludge on any engine that had its oil changed every 20 hours.

Click to expand...


I agree.
Not a bad idea to add a bottle of Lucas Oil Treatment, or STP either.
I put the Lucas in the motors on my boat this spring after the 1 year warranty period was over, and use STP in my 68 GTO motor.
The Lucas is compatible with the synthetic oil in the boat motors, and the STP is compatible with the blend in the GTO.
Both products leave a real nice slick coating on everything.
It might be overkill, but it doesn't hurt either.
 
Lots of different oils have been recommended, ranging from straight weights (30 or 40) to the diesel 15w/40 and the Merc 25/40. I used to use Chevron Delo straight 30 and then switched to the Merc 25/40. Not sure if there is really any difference, most likely not in my old engine. Of all the oils out there, the Merc is one of the few actually blended specifically for gas inboards. I think all these choices are fine, just don't use a light weight multi vis oil like 5w/30 or even 10w/30. They tend to thin out at the high revs common in marine inboard use. The straight weights definitely hold their viscosity better than any multi vis oil designed mainly for car use.

BTW, as a data point I noticed that the Delo straight weights used to be rated for both gas and diesel engines, now they are rated only for diesel, but the 15/40 is still rated for both.
 
quote:
Originally posted by mdoherty

I doubt you would see sludge on any engine that had its oil changed every 20 hours.

Click to expand...

Agree. After 21 years of low hours usage, it takes me 3 or 4 attemps to check the oil level. Merc used a plastic, gray, dip stick which is shiney and it becomes hard to see where the oil level mark is. The oil barely darkens over the course of 1 season of usage. I took some fine sandpaper and lightly scuffed the dipstick to make it dull. That has helped.
 
On a cold engine , one is reading much cleaner upper level oil which looks much cleaner /newer than lower level in the pan. A lot of people are fooled into thinking there oil is atill way cleaner than it really is. I never ever read on the 1st pull of the stick , warm or cold, as it gives false (higher ) reading. I always pull wipe reinsert fully , pull and roll the stick on a clean paper towel for best accuracy and always read the same side of the stick and likewise always re-insert with the ""710"" label facing the same way. Sticks that bend as they are inserted will read a bit differently on the 2 sides.

All that said, it sure seems quite a waste to pay for synthetic if changing annually with extremely low hours. FWIW,Crusader specs changes at 50 hrs for my 2003 engines, which I do several times a season using Valvoline All Fleet Plus (diesel and gas rated) SAE 15W -40. Economical HD oil frequently changed with NAPA-Gold filters. That said, at those oil changes the dipstick oil still reads almost ,even quite warm, but changed oil is pretty black with suspended solids, so perhaps synthetic would be beneficial after all even at short intervals. Note, I have a handy pan-drain remote Reverso gear pump oil changer system so essentially all flowable old oil is removed (no sludge buildup.).
(Crusader does finally say use of synthetic oil is OK now , but only if the original spec for oil & filter change interval is adhered to: every 50 hrs of operation or every 120 days whichever comes 1st.)
 
When I gave the example of never seeing sludge in an engine that uses synthetic oil I was referring to all the engines I've worked on and some of those have been high mileage auto engines. The dino tends to breakdown before it gets changed whereas the synthetic doesn't period. I agree that an engine that has low hours or low mileage between oil changes it probably doesn't matter. I know we are diligent with our boats but I've seen many cars that people routinely push the 3K oil change interval to 4K plus and don't think much of it. That was what I was talking about. I just had a friend call me to look at a 2008 Chevy with 60K on the clock busted timing chain due to dino routinely pushed to 5K,why did you think that was OK I asked he said the manual says 7500 miles between oil changes. I have to say that he didn't appreciate it when I said so how's that working out for you now? Anyway 8500 bucks for a new engine that only runs on synthetic oil.
Rob
 
I would use the best lubricating oil with the best tension retention (which are the primary qualities to prevent both wear and corrosion.
Synthetics fit this bill better than regular oil.
I use Royal Purple in my crusaders and I change it twice a year; once during winterizing and once mid season.
Cheap way to keep them running.
 
quote:
Originally posted by JVM225

I can't remember ever hearing of anyone blowing a motor because of the brand they used.

Click to expand...
While that is true, there is a difference in old school engines and the newer generation. Oil manufactures cater to the newer engines. There is quite a bit of pressure at the cam-lifter. This may become a problem on older non-roller lifter engines and those engines may see increased wear if the oil was not formulated for that. Thankfully, older boat engines do not have agressive lobes on the cam. Choosing a better oil for older designed engines is more important than choosing an oil for newer engines.
 
Pa Mikee is right. Usually motor oils labeled as "Racing Oil, or Off Road" still have some additives that are detrimental to catalytic converters. ZDDP was necessary for cam lifer lubrication. Read the labels.
 
The way some of you throw out perfectly good oil you must have money to burn. :-)

I run my high HP diesel engines on "dino" oil with bypass filters while doing regular oil analysis and rarely have to change the oil.

I've run diesel gensets with bypass filters, synthetic oil and regular oil analysis and never had to changed the oil.

In most cases oil doesn't wear out, it gets dirty. And with proper filtration that can be pretty much eliminated in a properly running engine. As long as things like the viscosity, fuel soot%, wear metals, additive package numbers, etc. are good, there is no need to change the oil. There are cases of trucks going hundreds of thousands of miles without an oil change. Some have hit a million.

I just change filters and add make up oil which refreshes the additive package while doing regular analysis.

Stuff like STP and other "motor honeys" are another total waste of money. Do you really think after doing 10 of millions of dollars worth and decades of research oil companies leave something out of their oil that makes adding snake oil like STP necessary or in any real way beneficial?

"Another type of additive is zinc dialkyldithiophosphate. Zinc-d is found in Mechanics Brand Engine Tune Up, K Mart Super Oil Treatment, and STP Engine Treatment With XEP2, among others. The touting of zinc-d as a special ingredient in engine oil additives is a little like the Shell ads which touted "Platformate." (Most gasoline has similar additives but under different names.) Zinc-d is an additive in most, if not all, major oil brands. The wonder oils just put more of the stuff in a 50 weight engine oil. It would be useful if your engine were ever operated under extremely abnormal conditions where metal contacts metal: "the zinc compounds react with the metal to prevent scuffing, particularly between cylinder bores and piston rings....unless you plan on spending a couple of hours dragging your knee at Laguna Seca, adding extra zinc compounds to your oil is usually a waste.... Also, keep in mind that high zinc content can lead to deposit formation on your valves, and spark plug fouling" (Rau).

If zinc-d is so good for your engine, why haven't oil manufacturers been putting more of it in their standard mix of oil and additives? Actually, oil companies have been decreasing the amount of zinc-d because the evidence indicates that zinc-d causes deterioration of catalytic converters.

The bottom line is that outside of the testimonials of happy and satisfied customers and the guarantees of company executives about the wonderful effects that studies have shown will follow the use of their products, there isn't much support for using oil additives. Of course, there are those millions of customers who buy the stuff: aren't they proof that these things really work? Not really. They're proof that this stuff really sells!"
 
Hey, Cap. Bill1, are you a list moderator as well as a captain?

This topic is boat related and obviously many find it interesting and worthy of discussion. If you don't....... then ignore it.
 
quote:
Originally posted by Padraig

Hey, Cap. Bill1, are you a list moderator as well as a captain?

This topic is boat related and obviously many find it interesting and worthy of discussion. If you don't....... then ignore it.

Click to expand...


Not sure how you read into my post that I in any way thought the topic was not worth discussion? In fact I thought I was adding to that discussion by pointing out ways to save money and conserve oil by using fact based methods of extending your engines oil change intervals.

So if that is of no interest to you, you feel free to ignore it.

Or perhaps you work for STP or some other motor honey company and I stepped in your rice bowl?
 
You must log in or register to reply here.
Back
Top