I have a new to me 2000 year Formula 26' with a Mercrusier 496 cid 375 HP with 130 hours on it. Would like to use synthetic. What synthetic oil has anyone used with good results. Thanks a lot!
What oil in 496 cid 375 HP Mercrusier
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Originally Posted By: lars11
Why do you want synthetic? I don't think Merc recommends that, more like advising against it as I recall.
He spun a bearing in his last boat on dino and it cost him $10,000 for the rebuild. The marina who did the repair told him to use M1 oil. Also the marina where he bought the Sea Ray told him to use M1 0-40.
Why do you want synthetic? I don't think Merc recommends that, more like advising against it as I recall.
He spun a bearing in his last boat on dino and it cost him $10,000 for the rebuild. The marina who did the repair told him to use M1 oil. Also the marina where he bought the Sea Ray told him to use M1 0-40.
I think some of the diesel oils seem to be popular in Marine applications. Rotella especially. Not sure whether the T-syn 5w40 or the dino 15w40 would be best.
Or a quality 10w40 like Mystik maybe??? My point is, that a more "heady-duty" oil is probably in order for a Marine application due to constant RPM's and pulling, etc. vs. say an regular car oil.
Or a quality 10w40 like Mystik maybe??? My point is, that a more "heady-duty" oil is probably in order for a Marine application due to constant RPM's and pulling, etc. vs. say an regular car oil.
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M1 0w-40 ??? I don't think so. Not in a marine engine.
Too Heavy a load and too much rpm for using 0w oil.
Use the Merc synthetic blend or the Merc 4 stroke oil
It's good stuff.
Too Heavy a load and too much rpm for using 0w oil.
Use the Merc synthetic blend or the Merc 4 stroke oil
It's good stuff.
Originally Posted By: BUBBA0420
M1 0w-40 ??? I don't think so. Not in a marine engine.
Too Heavy a load and too much rpm for using 0w oil.
Use the Merc synthetic blend or the Merc 4 stroke oil
It's good stuff.
0w40 is not a 0weight oil. That oil is 40 weight, nothing wrong with using it.
M1 0w-40 ??? I don't think so. Not in a marine engine.
Too Heavy a load and too much rpm for using 0w oil.
Use the Merc synthetic blend or the Merc 4 stroke oil
It's good stuff.
0w40 is not a 0weight oil. That oil is 40 weight, nothing wrong with using it.
"0w40 is not a 0weight oil. That oil is 40 weight, nothing wrong with using it."
Correct ... it is a 40 weight ... but this stuff used to have a reputation for shearing. Is that still the case? I think the constant stress of marine use would tear this stuff up ... and I don't see the point of its ultra-low pouring point being much of an advantage in a marine (fresh water) application where temps below freezing are very rare.
I'd use a 5W-40 if you want to go synthetic ... but still contend a 15W-40 is excellent for most marine applications. It's about picking one with the best add-pack ... Schaeffer, Chevron Delo, Pennzoil Long Life, etc ...
Correct ... it is a 40 weight ... but this stuff used to have a reputation for shearing. Is that still the case? I think the constant stress of marine use would tear this stuff up ... and I don't see the point of its ultra-low pouring point being much of an advantage in a marine (fresh water) application where temps below freezing are very rare.
I'd use a 5W-40 if you want to go synthetic ... but still contend a 15W-40 is excellent for most marine applications. It's about picking one with the best add-pack ... Schaeffer, Chevron Delo, Pennzoil Long Life, etc ...
No way, no how, would I ever use M1 0w-40 in this engine. This isn't a prissy German turbo crusier running dry roads. I don't care what the shop said. This stuff turns into a thick 20 under good conditions. I can't imagine what it becomes once you load it up with fuel and water.
Marine apps present unusual fuel dilution, high moisture and extreme shearing conditions all at once. Typical PCMOs don't handle that as well. The usual advantages of synthetics aren't as profound in this environment. Chemical stability is more important than anything else with a marine oil.
20w-50 racing (or M1 15w-50), HDEO 15w-40 or straight 30 or 40. Those are the better, customary, choices. Down south, I'd be eyeing straight weights. You can spend extra on synth if you want. But unless racing or really pushing it, conventional is just as good. Avoid ester oils except at very short changes (racing).
Marine apps present unusual fuel dilution, high moisture and extreme shearing conditions all at once. Typical PCMOs don't handle that as well. The usual advantages of synthetics aren't as profound in this environment. Chemical stability is more important than anything else with a marine oil.
20w-50 racing (or M1 15w-50), HDEO 15w-40 or straight 30 or 40. Those are the better, customary, choices. Down south, I'd be eyeing straight weights. You can spend extra on synth if you want. But unless racing or really pushing it, conventional is just as good. Avoid ester oils except at very short changes (racing).
Thanks for backing up my post above, Volvohead.
Can you tell me why so many marine users use a 20W-50 today? Is that weight really needed to support the mains these engines ... or is it assumed there will be some dilution and/or shearing early on in the oil use interval?
Seems to me most engines are burdened unnecessarily by this extra-heavy stuff.
Can you tell me why so many marine users use a 20W-50 today? Is that weight really needed to support the mains these engines ... or is it assumed there will be some dilution and/or shearing early on in the oil use interval?
Seems to me most engines are burdened unnecessarily by this extra-heavy stuff.
The heavier weights are needed to combat dilution and higher contamination rates. You don't need the heavier weight for the mechanical loads. But the oil will be chemically thinned out and its ability compromised. And the engines are typically running simultaneously under very high sustained shearing loads. All in all, a bad combination.
So, the answer is all of the above. And that is why the engines are perhaps initially burdened from a friction perspective running heavier weights, but in the end it is a good trade-off. The only alternative is running thinner weights at unreasonably short intervals, which can take the fun out of boating.
It doesn't make sense applying PCMO/thin oil philosophies to marine engines. The environment is completely different, and the consequences are very expensive.
20w-50 and 15w-40 are considered good compromise weights, which is why they are so popular.
So, the answer is all of the above. And that is why the engines are perhaps initially burdened from a friction perspective running heavier weights, but in the end it is a good trade-off. The only alternative is running thinner weights at unreasonably short intervals, which can take the fun out of boating.
It doesn't make sense applying PCMO/thin oil philosophies to marine engines. The environment is completely different, and the consequences are very expensive.
20w-50 and 15w-40 are considered good compromise weights, which is why they are so popular.
Volvohead, What is your opinion of 5-50 Castrol Syntec for marine use? Would you say it is like your description of 20-50 and 15-50 or you would not use it like your description of 0-40?
Thanks!
Thanks!
callbay, while waiting for Volvohead,
I would say that Castrol Syntec is something in-between those other oils ... and would not be my first (or second or third choice). Even a synthetic with that wide a spread is prone to shearing ... and I haven't seen a UOA of that stuff in a while so I can't comment on the add-pack ... but it's a PCMO so it's at least suspect.
The fleet/diesel/marine 15W-40s are pretty widely available (and economical) so those would be my first pick. At any sign of shearing or unstable oil pressure (yes, I would do a few UOAs and watch the gauges like a hawk until I got consistent results) I might step up to one of the aforementioned 20W-50s with Max-Life 20W-50 probably being my first pick among those.
I would say that Castrol Syntec is something in-between those other oils ... and would not be my first (or second or third choice). Even a synthetic with that wide a spread is prone to shearing ... and I haven't seen a UOA of that stuff in a while so I can't comment on the add-pack ... but it's a PCMO so it's at least suspect.
The fleet/diesel/marine 15W-40s are pretty widely available (and economical) so those would be my first pick. At any sign of shearing or unstable oil pressure (yes, I would do a few UOAs and watch the gauges like a hawk until I got consistent results) I might step up to one of the aforementioned 20W-50s with Max-Life 20W-50 probably being my first pick among those.
Originally Posted By: callbay
Volvohead, What is your opinion of 5-50 Castrol Syntec for marine use? Would you say it is like your description of 20-50 and 15-50 or you would not use it like your description of 0-40?
Thanks!
I'd shy away from it. It's likely a Group III with a complex VII package. Oils with more complex VI chemistry, such as M1 0w-40, are outstanding performers in automotive use, but not necessarily the best pick here. I'm not saying it won't work out just fine, but there is a higher risk of problems with them. Whether you want to take that risk with a $15,000+ marine engine is up to you.
I know that this is entirely counterculture to what's propounded elsewhere around BITOG. But the unique conditions of marine duty really separate the men from the boys chemically. The marine lubricating environment is almost neanderthal compared to what goes on on land. High tech doesn't necessarily work in a lot of marine engines, which, by the way, are at heart still low tech themselves. Things like FWC and FI help, but it's still a wet, fuel rich environment.
I'm not saying to run QS HD30. But oils that are generally chemically very stable tend to put up with marine conditions better. The only auto analogy I can come up with is a BMW engine recently discussed on an import oil thread that was destroying PCMOs with high shear/high fuel dilution conditions. BMW's solution was . . . a higher viscosity oil. And from the post, the only other oil that could put up with it was RLI.
Volvohead, What is your opinion of 5-50 Castrol Syntec for marine use? Would you say it is like your description of 20-50 and 15-50 or you would not use it like your description of 0-40?
Thanks!
I'd shy away from it. It's likely a Group III with a complex VII package. Oils with more complex VI chemistry, such as M1 0w-40, are outstanding performers in automotive use, but not necessarily the best pick here. I'm not saying it won't work out just fine, but there is a higher risk of problems with them. Whether you want to take that risk with a $15,000+ marine engine is up to you.
I know that this is entirely counterculture to what's propounded elsewhere around BITOG. But the unique conditions of marine duty really separate the men from the boys chemically. The marine lubricating environment is almost neanderthal compared to what goes on on land. High tech doesn't necessarily work in a lot of marine engines, which, by the way, are at heart still low tech themselves. Things like FWC and FI help, but it's still a wet, fuel rich environment.
I'm not saying to run QS HD30. But oils that are generally chemically very stable tend to put up with marine conditions better. The only auto analogy I can come up with is a BMW engine recently discussed on an import oil thread that was destroying PCMOs with high shear/high fuel dilution conditions. BMW's solution was . . . a higher viscosity oil. And from the post, the only other oil that could put up with it was RLI.
My boss has a 454 Mercruiser, and had many problems with it until he ran Castrol Syntec 20w50.
I'm not going to say that it is the best, but it certainly works.
I'm not going to say that it is the best, but it certainly works.
Marine engines get:
1. serious fuel dilution
2. serious corrosion issues from sitting for long periods
3. heavy shock loading from running 3200-4500 rpm all day
I would only go with Merc 25w40 dino or syn blend oil or a similar 40w marine rated oil like Pennzoil. Some guys use a 15w40 HDEO but chenge them often.
I have twin 454 cid EFI 380 HP Mercury Horizon engines that I run on Merc dino 25w40 and they run fantastic after 9 years. I change oil at 50 hours. The factory OCI for my engines is 100 hours. I was going to ise a 15w40 but my marine wrench told me not to run it past 30 hours which is a PIA for me to change oil that often. The Merc oils have no VII's in them and are very shear stable.
1. serious fuel dilution
2. serious corrosion issues from sitting for long periods
3. heavy shock loading from running 3200-4500 rpm all day
I would only go with Merc 25w40 dino or syn blend oil or a similar 40w marine rated oil like Pennzoil. Some guys use a 15w40 HDEO but chenge them often.
I have twin 454 cid EFI 380 HP Mercury Horizon engines that I run on Merc dino 25w40 and they run fantastic after 9 years. I change oil at 50 hours. The factory OCI for my engines is 100 hours. I was going to ise a 15w40 but my marine wrench told me not to run it past 30 hours which is a PIA for me to change oil that often. The Merc oils have no VII's in them and are very shear stable.
Originally Posted By: PT1
Marine engines get:
1. serious fuel dilution
I'm boat dumb. Why more fuel dilution than any other engine?
Marine engines get:
1. serious fuel dilution
I'm boat dumb. Why more fuel dilution than any other engine?
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