Dixie Life
Senior Member
Time to change my oil on the FL120. I'm planning on refilling with Mobil1 syn for diesels. Any advice?
Syn Oil?
- Thread starter Dixie Life
- Start date
The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Baggiolini
Senior Member
I'm in the same quandary. Guy on the dock who has the same power set up 6BT/Twindisc 502, who runs a dive boat when to synthetic but I'm not so sure about changing what she has known for 22 years.
Nomad Willy
Guru
Synthetic oil dos'nt have any benefits unless your'e racing or for some other reason running your engine at the ragged edge heat wise. Buy regular oil (30W) and change twice as often. Then you will actually be doing your engine a favor. But synthetic oil is better than refined crude in every way except price. But you wo'nt experience any benefits unless you run your oil around 300 degrees. I change my oil frequently but I change the filter every third time. In the relatively dust/dirt free environment of the engine compartment of a boat it would take years to trap enough stuff to require a filter change. Whatever type or brand you use make sure the duty rating (like SJ) is recommended by your engine manufacturer. Follow the manufacturer before dealers and mechanics. Manufacturers formulate their recommendations from engineers.
Conrad
Guru
- Joined
- Oct 19, 2007
- Messages
- 1,972
- Location
- Canada
- Vessel Name
- Blue Sky
- Vessel Make
- Nordic Tugs 42 Hull #001
Not sure I can add anything, but we have synthetic (Amsoil) in our Volvo; the previous owner had always used it (he was an Amsoil rep) and swore by it, not surprisingly. He suggested an easy 500 - 600 hours between changes which sounds like a stretch, although the engine also has an oil bypass filter which I'm sure helps.
The key thing to remember is that you cannot mix conventional and synthetic oils. And synthetic is very expensive. Our engine has approximately 4500 hours on it and just purrs along.
The key thing to remember is that you cannot mix conventional and synthetic oils. And synthetic is very expensive. Our engine has approximately 4500 hours on it and just purrs along.
Fotoman
Guru
- Joined
- Nov 12, 2009
- Messages
- 649
I don't thnk you want to do that. There was some previous discussions on this forum about that. I don't remember the detais but bottom line these engines were made way before synt oil and they would probably not take it too well. In any event, you should call American Diesel to ask them.
Phil Fill
Guru
- Joined
- Oct 11, 2007
- Messages
- 2,919
- Location
- US
- Vessel Name
- Eagle
- Vessel Make
- Roughwater 58 pilot house
I would not use a syn in an older diesel engine especially an older 2 stroke and/or if syn is multi weight when the mfg recommend is single weight. Make sure it meets the mfg requirement.
I have heard on other forums from people who say they have run synthetics in an engine like the FL120 with no problems. However when we bought our boat one of the first questions I asked was what kind of oil should we use. The answers from people ranging from engineers in the marine diesel manufacturing industry to our local diesel shop to long -time operators of similar engines was "use what the manual recommends." In the case of the FL120 in this climate, that is 30 wt oil. So that's what we have used for the last 13 years--- Delo 400 30wt.
I have heard the reasons not to use synthetic in an old technology diesel, particularly one with a fair number of hours on it. Leaking seals and gaskets, less-than-ideal lubrication immediately after starup, and so forth. Since we have never run synthetic in our engines I cannot say from experience whether these potential problems are real or not.
I was told by the fellow in the marine diesel design and manufacturing industry that if we had our FL120s completely rebuilt using seals and gaskets of the "right" materials, then using synthetic oil would probably be okay. My wife's new Subaru calls for synthetic oil exclusively and this is a growing trend with the latest generation engines.
But for an old thumper like the FL120, I will stick with the oil it was designed to use, which is single weight dinosaur oil. These engines have a reputation for going some 12,000-14,000 hours in recreational boat service assuming regular use and proper operation and maintenance. At that rate the engines will outlast me probably. So I see no reason to switch to a different and more expensive oil for either no benefit or one that nobody will ever realize. The engines will most likely fail for some other reason long before the lubrication advantages of dinosaur or synthetic oil make any difference.
I have heard the reasons not to use synthetic in an old technology diesel, particularly one with a fair number of hours on it. Leaking seals and gaskets, less-than-ideal lubrication immediately after starup, and so forth. Since we have never run synthetic in our engines I cannot say from experience whether these potential problems are real or not.
I was told by the fellow in the marine diesel design and manufacturing industry that if we had our FL120s completely rebuilt using seals and gaskets of the "right" materials, then using synthetic oil would probably be okay. My wife's new Subaru calls for synthetic oil exclusively and this is a growing trend with the latest generation engines.
But for an old thumper like the FL120, I will stick with the oil it was designed to use, which is single weight dinosaur oil. These engines have a reputation for going some 12,000-14,000 hours in recreational boat service assuming regular use and proper operation and maintenance. At that rate the engines will outlast me probably. So I see no reason to switch to a different and more expensive oil for either no benefit or one that nobody will ever realize. The engines will most likely fail for some other reason long before the lubrication advantages of dinosaur or synthetic oil make any difference.
Last edited:
jleonard
Guru
- Joined
- Jun 25, 2008
- Messages
- 5,063
I wouldn't change to synthetic mainly for fear the seals would start leaking. I could see advantages though especially to reduce wear from a dry start, but that may be more theory than practicality.
I believe in keeping consistant with oil brand and type. That is why I continue to use 15-40 in my Lehman becuase the previous owners used that.
Funny that many become really passionate about oil brand when in fact there are few failures that are oil brand related.
I believe in keeping consistant with oil brand and type. That is why I continue to use 15-40 in my Lehman becuase the previous owners used that.
Funny that many become really passionate about oil brand when in fact there are few failures that are oil brand related.
psneeld
Guru
What I have read (thousands of pages of tech reference).....is that syn oil for the average user (driver or boater) is you are wasting your money unless you do oil anaysis and change your oil based on that (even then you can argue tha dino oil is satisfactory).
The trick is that oil is changed when either particulate accumulation or oil ph/additive formulations are no longer doing their job.
Almost universally a 200 hr oil change of dino oil with filter if your engine is still pretty normal and your engine will last as long as it was meant to and oil won't be the reason it fails.
Syn oil is OK to use....multi-weight is OK to use...single weight is OK to use unless operating over a temp range that single weight would prevent easy starts.
A lot of discussion about seals and everything else is hit or miss depending on the oil and engine...but for the most part modern oils are so superior to the older engines and components...almost anything you use, mix or anything else winds up being OK unless you are subjecting your engine to severe service...which most of us aren't because there's the constant crap about running our engines "underloaded".
The trick is that oil is changed when either particulate accumulation or oil ph/additive formulations are no longer doing their job.
Almost universally a 200 hr oil change of dino oil with filter if your engine is still pretty normal and your engine will last as long as it was meant to and oil won't be the reason it fails.
Syn oil is OK to use....multi-weight is OK to use...single weight is OK to use unless operating over a temp range that single weight would prevent easy starts.
A lot of discussion about seals and everything else is hit or miss depending on the oil and engine...but for the most part modern oils are so superior to the older engines and components...almost anything you use, mix or anything else winds up being OK unless you are subjecting your engine to severe service...which most of us aren't because there's the constant crap about running our engines "underloaded".
Nomad Willy
Guru
The seal issues using synthetic is an old problem and was completely solved years ago. All modern synthetics have an additive to counteract the effect on seals. It was swelling or shrinking.....can't remember which.
As for synthetics in older engines the're just as good of a waste of money in an old engine as a new one. Put syn in your Model A if you want.
Also one should consider that synthetic oil probably needs no viscosity improvers to achieve a multi-vis rating. Viscosity wise synthetic oil dos'nt thicken and thin out as much as dino oil does when heated and cooled. The bottom line is that you do'nt need it at all. Ther'es no downside though beyond the loss of your money.
As for synthetics in older engines the're just as good of a waste of money in an old engine as a new one. Put syn in your Model A if you want.
Also one should consider that synthetic oil probably needs no viscosity improvers to achieve a multi-vis rating. Viscosity wise synthetic oil dos'nt thicken and thin out as much as dino oil does when heated and cooled. The bottom line is that you do'nt need it at all. Ther'es no downside though beyond the loss of your money.
HopCar
Guru
- Joined
- Aug 20, 2011
- Messages
- 5,308
- Vessel Name
- Possum
- Vessel Make
- Ellis 28
I spoke to our oil supplier about this just a couple of months ago. Among other things he said it was bad to switch an engine that had been running on petro oil for many years to synthetic. He seemed to think it was a good idea for new engines that were run enough to require frequent oil changes. The extended run time on synthetic oil made it more economical. If you only change your oil once or twice a year, it's not worth the extra cost.
- Joined
- Jun 25, 2008
- Messages
- 10,104
- Location
- Australia
- Vessel Name
- Now boatless - sold 6/2018
- Vessel Make
- Had a Clipper (CHB) 34
That's my take on it as well. Same for cars. No real point putting expensive synthetic oil in an older car, but from new yes, so one can take advantage of a significantly longer service interval. Ditto boats. However, I did depart from Marin's "follow the manual literally" advice a bit, and I use 15-40 Castrol Magnetec Diesel in my FL120, and it has been running great, and even tho she has done well over 4000hrs (hr meter now broken, so no real idea), uses virtually no oil between annual seasonal changes.
JD
Guru
I'm sorry but I can't agree with this 100%. It may have been true for an engine that was built in 1970 but remember the engineers didn't have at their disposal the things that are at the disposal of engineers today.
As an example what if you had a heart attack today and the Dr. that came into the room to treat you was 90 years old and he said "take two aspirins and get a lot of bed rest" because that was the way they did it when he got out of medical school in 1950. Would you do that or would you like to have the triple by pass, or valve replacement that has saved so many people in the last 40 years?
The point is that there are oils and lubricants that are available today that were not even thought of when your engine was built so there was no way for the manual to recommend them. Read the side of the can. If it meets or exceeds the SAE Specs for your engine it will not hurt your engine.
Nomad Willy
Guru
JD,
Of course syn will not hurt your engine. It's better except for the price so how is it going to hurt your engine? But Peter there's not point in putting syn in anything unless it's going to get real hot and experience extreme pressure and our trawlers and cars do'nt do that so syn oil is just a waste of money. Syn oil dos'nt wear out so quickly but it accumulates carbon just as fast and many to most say it's the carbon that wears out the engines. If I had an old car w lots of miles on it I'd put syn oil in it but only if someone gave me the syn oil.
Of course syn will not hurt your engine. It's better except for the price so how is it going to hurt your engine? But Peter there's not point in putting syn in anything unless it's going to get real hot and experience extreme pressure and our trawlers and cars do'nt do that so syn oil is just a waste of money. Syn oil dos'nt wear out so quickly but it accumulates carbon just as fast and many to most say it's the carbon that wears out the engines. If I had an old car w lots of miles on it I'd put syn oil in it but only if someone gave me the syn oil.
According to the car people synthetics are recommended for a lot of new cars (like our Subaru) because the new engines have extremely tight tolerances and need that type of oil.
A former neighbor bought a 40th Anniversary special Corvette when they came out and on that car the factory warranty was immediatley voided if you put anything other than the recommended synthetic in it. The manual for our Subaru specifies synthetic (0-20 wt) but says that "in an emergency" regular oil (aka dinosaur oil) can be used but the oil must be changed back to the 0-20 wt synthetic at the first opportunity. Extremely tight tolerances is the reason given.
A former neighbor bought a 40th Anniversary special Corvette when they came out and on that car the factory warranty was immediatley voided if you put anything other than the recommended synthetic in it. The manual for our Subaru specifies synthetic (0-20 wt) but says that "in an emergency" regular oil (aka dinosaur oil) can be used but the oil must be changed back to the 0-20 wt synthetic at the first opportunity. Extremely tight tolerances is the reason given.
FF
Guru
- Joined
- Oct 12, 2007
- Messages
- 22,552
"Of course syn will not hurt your engine. It's better except for the price so how is it going to hurt your engine?"
EASY, its special effects can HARM the engine by reducing protection.
The Syn oil is great oil for extreme loads and high heat,but it is created to scrape easier off the cylinder walls.
This will give the engine 1 to 1 1/2 better fuel burn . But the chemistry that lets it scrape off also helps it run off.
A few days after an engine is shut down there may not be enough residual oil on the cylinder walls to keep them from rusting.
Less of a problem on a truck operated 250 days a year .
BUT on a boat with the usual wet exhaust there is frequently water in the exhaust all the time.Esp if a muffler or water lift silencer is aboard.
The choice of 1% better fuel burn VS rusty cylinder walls keeps me on std oil , and fogging fluid when there will be a known stand down time.
FF
EASY, its special effects can HARM the engine by reducing protection.
The Syn oil is great oil for extreme loads and high heat,but it is created to scrape easier off the cylinder walls.
This will give the engine 1 to 1 1/2 better fuel burn . But the chemistry that lets it scrape off also helps it run off.
A few days after an engine is shut down there may not be enough residual oil on the cylinder walls to keep them from rusting.
Less of a problem on a truck operated 250 days a year .
BUT on a boat with the usual wet exhaust there is frequently water in the exhaust all the time.Esp if a muffler or water lift silencer is aboard.
The choice of 1% better fuel burn VS rusty cylinder walls keeps me on std oil , and fogging fluid when there will be a known stand down time.
FF
JD
Guru
I'm not advocating the use of Syn in an older engine. I was just pointing out that if the Specs on the can indicate it is better than the original requirement it will not hurt the engine.
My experience with Syn has been positive so far. The 2001 Audi TT we had went 120k miles with out a leak, never burned a drop between the 10k recommended oil changes and never had a lubrication problem. My 2003 Mercedes has 152k miles on it, has used Syn oil as well and has had the same results as has my 2010 VW TDI with over 59k miles. Now is it the oil or just better engines. I don't know but what I do know is that the sun glasses I wear have been advertised to keep Pink Elephants away and in the last ten years they have worked flawlessly. So maybe it is the same for the Syn oil.
My experience with Syn has been positive so far. The 2001 Audi TT we had went 120k miles with out a leak, never burned a drop between the 10k recommended oil changes and never had a lubrication problem. My 2003 Mercedes has 152k miles on it, has used Syn oil as well and has had the same results as has my 2010 VW TDI with over 59k miles. Now is it the oil or just better engines. I don't know but what I do know is that the sun glasses I wear have been advertised to keep Pink Elephants away and in the last ten years they have worked flawlessly. So maybe it is the same for the Syn oil.
Daddyo
Guru
I asked Bob Smith himself about this last year. Bottom line is he said it was fine but use single weight SAE30. He didn't see much benefit other then the longer cycle between changes. The other experts I've spoken with are Zimmerman Marine and they say it will actually make the engine run quieter with the synthetic. As to the cost it is actually a little cheaper the conventional oil when you factor in the savings of double life of the oil and half as many filter changes.
I thought some commercial oils are just that - a blend of synthetic and "dino" oil. Am I wrong on that?
The guy at the local Jiffy Lube keeps trying to get me to put synthetic oil (at a $50 upcharge) in my 2007 Toyota with 65K miles on it. He says it's recommended.
I suppose I might get 2% better gas mileage, but I don't think there would ever be a payback.
My Volvo diesel (in my boat) has 3K hours on it with dino oil and it's running fine. I think I'll let well enough alone.
I suppose I might get 2% better gas mileage, but I don't think there would ever be a payback.
My Volvo diesel (in my boat) has 3K hours on it with dino oil and it's running fine. I think I'll let well enough alone.
- Joined
- Oct 6, 2007
- Messages
- 841
- Location
- Poulsbo, WA
- Vessel Name
- Dream Catcher
- Vessel Make
- Nordic Tug 37-065
Another reason to stick with a readily available quality dino oil: I can get Delo 15-40 just about anywhere along the Inside Passage, and I need to change the oil 3-5 times each summer.
psneeld
Guru
True for tannies and gearboxes...problem with combustion engines is the acidity builds...so without oil analysis doubling the interval can be an iffy thing....probably OK if the hrs are accumulated over a short calendar period.
psneeld
Guru
I run the Rotella 5W-40 in my truck in the winter and I'm pretty sure it's a blend and not a true syn like Mobile 1.
Some oil "experts" believe a blend is better in the long run for normal use because it clings better as FF was pointing out. (best of both worlds without downsides other than it will cook faster at higher than normal operating temps but unfortunately twice the price)
Conrad
Guru
- Joined
- Oct 19, 2007
- Messages
- 1,972
- Location
- Canada
- Vessel Name
- Blue Sky
- Vessel Make
- Nordic Tugs 42 Hull #001
I'm just going by what the mechanics have told me; that applies to the boat, and all three of my vehicles. The blends may have some peculiarities that allow them to coexist, I don't know.
Having said that, another "truism" that I've been told over the years is that you never use synthetic oil to break in a new engine. Yet when you look at Amsoil's site they say you can.
Given the choice, I'd probably stay conventional, as it just makes life simpler.
Phil Fill
Guru
- Joined
- Oct 11, 2007
- Messages
- 2,919
- Location
- US
- Vessel Name
- Eagle
- Vessel Make
- Roughwater 58 pilot house
A big difference is if the engine is a 2 stroke or 4 stroke. If 2 stoke the oil need to be thick and cling, and low sulfur/detergent. The reason is at least one cylinder on a 2 stroke is open at any time. Thus the cylinder wall should have a think lasting clingy coating if not run for long periods of time. It is also recomend to turn/bump/start the engine every once in a while. Second is the sulfur/detergent as a two stock cylinder ride on a thin film of oil, and some oils are to thin and clean. Anyway I will only use single 30 or 40 weight oil in the Eagle 1978 engines.
As to when oil is change it is dependant on the corbon and sulfur and/or how dirty the oil is. If you take oil samples you can push oil chnages to 200+ hours. You can buy test kits at many marine stores. I am not sure where the 100 hour or 3,000 miles came from? It use to be 200 hours and 5,000 miles?
We had some great discussion in the past and I ma to lazy to go find pull out the detail again. So you newbies can do it as us older have already been thorugh it and decided.
As to when oil is change it is dependant on the corbon and sulfur and/or how dirty the oil is. If you take oil samples you can push oil chnages to 200+ hours. You can buy test kits at many marine stores. I am not sure where the 100 hour or 3,000 miles came from? It use to be 200 hours and 5,000 miles?
We had some great discussion in the past and I ma to lazy to go find pull out the detail again. So you newbies can do it as us older have already been thorugh it and decided.
Nomad Willy
Guru
Richard,
Yes.....That's one of the reasons I use the same brand but I do not use multi-vis. I think that unless we have some trouble cranking in low temps multi-vis is totally not needed. For the same reason I have a bronze Jabsco sea water pump. Any NAPA in SE has impellers.
psneeld,
I agree. Half the interval w inexpensive dino oil seems much more effective. I believe good quality dino oil like Shell or Chevron is 100% as good as synthetic if not over stressed and you could run your non-turbo'd at WOT for hours and not over stress your oil. And I'll bet you could run a turbo engine on dino oil at at least 80% load and it looks like nobody here does that. If you put straight 30W or 40W in your engine and do'nt have trouble cranking and starting you're good to go w 100% dino.
Conrad,
Mechanics are not engineers and remember that mechanics told us for decades not to put a battery on concrete? We all know that was/is total bunk now but most everybody bought into that. Not using syn for break-in comes from the belief that there is not enough engine wear properly seat the rings. I do'nt know if that's true (I suspect not) but it wont hurt to break in w dino and for that matter it wont hurt to run dino for the whole engine's life.
Phil Fill,
I agree .......30 or 40 weight oil for our boat engines. I'll talk about it again as that's what we do on TF.http://www.trawlerforum.com/forums/images/trawler/smilies/sk/dance.gif
Yes.....That's one of the reasons I use the same brand but I do not use multi-vis. I think that unless we have some trouble cranking in low temps multi-vis is totally not needed. For the same reason I have a bronze Jabsco sea water pump. Any NAPA in SE has impellers.
psneeld,
I agree. Half the interval w inexpensive dino oil seems much more effective. I believe good quality dino oil like Shell or Chevron is 100% as good as synthetic if not over stressed and you could run your non-turbo'd at WOT for hours and not over stress your oil. And I'll bet you could run a turbo engine on dino oil at at least 80% load and it looks like nobody here does that. If you put straight 30W or 40W in your engine and do'nt have trouble cranking and starting you're good to go w 100% dino.
Conrad,
Mechanics are not engineers and remember that mechanics told us for decades not to put a battery on concrete? We all know that was/is total bunk now but most everybody bought into that. Not using syn for break-in comes from the belief that there is not enough engine wear properly seat the rings. I do'nt know if that's true (I suspect not) but it wont hurt to break in w dino and for that matter it wont hurt to run dino for the whole engine's life.
Phil Fill,
I agree .......30 or 40 weight oil for our boat engines. I'll talk about it again as that's what we do on TF.http://www.trawlerforum.com/forums/images/trawler/smilies/sk/dance.gif
psneeld
Guru
From what I read on battery manufacturer websites was that when batteries had rubber cases...moisture (concrete) was a problem but when batteries switched to plastic cases it became moot.
I've been debating the multi-viscosity issue as my boat lived 22 years in South Florida and now NJ till at least freezing temps are experienced. Hard not to think 15W-40 isn't my best solution as it is one of the most recommended oils for diesels in the mid-Atlantic region.
Sometimes, mechanics aren't experts, they are just good at repairing things.
The multi-vis question is an interesting one. When we bought our boat and I asked the experts I knew at the time what oil they felt would be best for the engines (1973 FL120s) all of them recommended single-weight oil and all of them advised against multi-viscosity. This included the head of the engineering department of one of the marine industry's most respected propulsion and generator manufacturers. At the time I asked the question (1998) he said that their current lineup of propulsion and generator diesels all used multi-vis and some even used synthetic. But for very old generation engines like the FL120, he said they recommend sticking with a single-weight oil.
He had some reasons which unfortunately I didn't actually pay much attention to at the time since I got my basic question answered and it jibed with the engine manufacturer's manual. But I have since seen a very detailed discourse on the T&T list from a fellow in the oil industry about the pros and cons of multi-vis oil in engines like the FL120 and there were some issues with multi-vis that appeared to be less than ideal. I believe it had to do with the reaction of the oil as it gets hot and that lubricity is actually lost to a degree. I could be misremembering the reason the oil guy gave for multi-vis being less than ideal for older diesels, but whatever the reasons were they made sense. Unfortunatly T&T has the most user-unfriendly archives search function I've ever seen and trying to unearth this discussion today would become a career.
However..... while the 1973-vintage Ford and Lehman operator's manuals for our engines specify single weight oil only based on the ambient temperatures the engine will be operated in, later versions of the Lehman manual for the same engine include multi-vis oil in the lubrication chart. The operators manual for my 1973 Land Rover, which has an engine Rover designed as a diesel and then later adapted for gas (a long story in itself), specifies multi-vis oils.
So I'm not sure what the real story is. But we have elected to follow the advice we were originally given and that our manual calls out, which is to use single-weight oil only. For our climate, the recommended weight is 30.
Last edited:
