penfold
Well-known member
That's fine, but given a oil test costs about as much as an oil change on a small boat diesel it's a bit pointless. If you have a big mobo then undoubtedly it makes sense, but not for the little guy.
Why won't oil last in a marine engine?
- Thread starter Nostrodamus
- Start date
That's fine, but given a oil test costs about as much as an oil change on a small boat diesel it's a bit pointless. If you have a big mobo then undoubtedly it makes sense, but not for the little guy.
Sans Bateau
Well-known member
Interesting reading Brian, however if I were to follow your oil changing discipline I dont think I'd live long enough to do even one oil change! You see in 18 years my boat has only done around 1400 engine hours, so you see to change at 5000 hours would take 64 years! See, people who sail only use their engines when they have too.
I have to ask, the 40 - 50 year old engines you are responsible for, if one goes bang, do you have to put your hand into your pocket to fix or replace it?
So as a technical type of owner I would rather join the non technical types who change their oil every year, seeing the economics are better weighted spending 20 or 25 quid a year for peace of mind.
I have to ask, the 40 - 50 year old engines you are responsible for, if one goes bang, do you have to put your hand into your pocket to fix or replace it?
So as a technical type of owner I would rather join the non technical types who change their oil every year, seeing the economics are better weighted spending 20 or 25 quid a year for peace of mind.
jordanbasset
Well-known member
For my engine, a Volvo d2-55, it is every 500 hours or once a year, as others have said the cost is not great and takes about 15 minutes. Okay then another hour or so to clean the mess I made...
Nostrodamus
New member
There are a lot of differing replies here as I would have expected and it makes it as clear as used oil.
So I either change my oil once a week or every 64 years. Got that.
Does using the manufactures oil or a cheap oil make any difference, what is better for your engine, mineral or synthetic and does anyone put any additives in?
So I either change my oil once a week or every 64 years. Got that.
Does using the manufactures oil or a cheap oil make any difference, what is better for your engine, mineral or synthetic and does anyone put any additives in?
Sans Bateau
Well-known member
Whatever your engine manufacturer recommends, but its unlikely to be synthetic unless your engine is latest technology.
brianhumber
New member
Bought a number of test kits in one go a few years ago so cost is between £10/£15 for each test. I have learnt its not needed to get a laboratory full test every year, I do a simple water/viscosity test inbetween so it is cheaper than changing oil.
Very unlikely the old engines will go bang as the ratings are very conservative as normal for engines of that era. They have had oil condition monitoring since the 60s by the way. Instrumentation and controls are more difficult granted but I find its plant with the early electronic kit from the 70s and 80s which is very difficult to repair/keep going.
As an aside I read that one of the last signal boxes in the country will be the 1930s one at Bognor Regis as its mechanical/early dc equipment can be kept in repair far easier than the first generation of electronic signal boxes such as Three Bridges/London Bridge built in the 1970s. These will all be going first as spare electronic parts/relays cannot be sourced.
I suspect it will not be many years before one buys a car with the engine in a box sealed for life. Any problems, just change the engine rather like batteries. Technically this is possible to do now. My last two cars were changed with the engine still in very good condition ( again with minimal oil changes ) but after 200/300k the suspension was uneconomic to repair to pass the MOT
Brian
GrahamM376
New member
Most older boat engines are low tech and can be equated to a car of the same age and normal oil changes then were 5,000 miles which equates roughly to the 100hrs on boats. In common with other posters, I tend to change my oil annually and, if I'm lifting out in winter do it immediately before, to avoid damage from acidic contaminants.
Nostrodamus
New member
So just to clarify.
It is better to change too often that to little but in any case at least once a year.
Change before winter if the engine is going to be idle and not before the season starts.
Use good oil asspecified by the manufacturer (do not use synthetic where mineral is suggested and visa versa.
Change the oil filter at the same time.
If the boat is not being used should the engine be turned over from time to time to lubricate?
It is better to change too often that to little but in any case at least once a year.
Change before winter if the engine is going to be idle and not before the season starts.
Use good oil asspecified by the manufacturer (do not use synthetic where mineral is suggested and visa versa.
Change the oil filter at the same time.
If the boat is not being used should the engine be turned over from time to time to lubricate?
prv
Well-known member
There was a car a few years ago with no opening bonnet. Just a little flap above the radiator with the dipstick and the fillers for various fluids.
I suppose that was more a marketing gimmick than anything - appeal to those who are intimidated by engines - as there was still a big access panel that would be removed by the dealer for all the servicing you'd have to pay them for.
Pete
colind3782
Well-known member
Sans Bateau
Well-known member
Granted, but that might be because the CAA would not want a Ryan Air hostie poking around in the engine of an airbus!
GrahamM376
New member
Is it worth it when you can buy 5L of uncontaminated new oil for under £15?
pmyatt
New member
Nearly right, but not quite. Conventional filters are full-flow, meaning that they filter all the oil on each circulation; for this they cannot be too fine. Fit a high-pressure by-pass filter from a T-piece to the oil pressure switch with the return to either the sump or the rocker cover and you can run a truck engine for 1 million km without an oil change; just regular top-ups and by-pass filter changes (main filter remains unchanged) and, as an emergency, you can use a roll of paper kitchen towel or a toilet roll as the filter. Filtering is down to about 1 micron and the paper absorbs all water. Both German and US truck operators use them as does the US Army for it's truck and Abraham tanks.
vyv_cox
Well-known member
The values quoted are incorrect. The TBN of API CC is 3, CD is 4 and CF4 (from memory) is about 10. Using an oil with a TBN of 30 in a marine diesel would be a recipe for high wear rates.
This type of engine has separate trunk (= crankcase) oil and combustion oil. The crankcase oil sees virtually no contaminants. The combustion oil is once through, burnt with the fuel, and may have a TBN as high as 100.
contessaman
Member
for what its worth I had an old ford escort van 1.8 diesel. it was old and high milage but well serviced when I bought it. I used to drive it like I stole it, but I changed the oil every year. It was still pulling like a train when I sold it with 268,000 on the clock. The van will have doubtless rusted away before the engine died.
I really dont think that changing the oil & filter on the boat engine is much work or even costly, so it has to be well worth doing at the end of every season. that, the fuel filter and new impellor kit all comes in at under a ton and can be done in a days work, so why not?
I would never bother with manufacture branded oil though - unless you need it to keep up a warranty.
I really dont think that changing the oil & filter on the boat engine is much work or even costly, so it has to be well worth doing at the end of every season. that, the fuel filter and new impellor kit all comes in at under a ton and can be done in a days work, so why not?
I would never bother with manufacture branded oil though - unless you need it to keep up a warranty.
ffiill
Active member
By all means change your oil in your car ever 12000 miles or more but engine will last a lot longer if you change every 6000 miles. 6000 miles I estimate is the equivalent of about 100 hours at 2000 rpm(my cruising speed) assuming 60mph at 2000 rpm in a diesel car.
So I change the oil every 100 hours and every year come what may and every 6000 mies on my car.
So I change the oil every 100 hours and every year come what may and every 6000 mies on my car.
ffiill
Active member
My merc om636 has a traditional cleanable filter which has done alright for past thirty years.
The bottom line is that the oil slowly picks up dirt and metal however fine and insignificant which particularly will get embedded in the white metal of the bearing shells and cause differential wear ie the soft material effectively wears down the hard.
So keeping the engine clean by regular oil and filter changes is always the best deal.
I just use a general mineral multigrade whether in boat or car but one reccomended for Turbos if in a turbocharged engine.
vyv_cox
Well-known member
Ah, those were the days! Scraping bearings after recasting, what joy.
Can't speak for Merc OM36 engines but no modern engines, either diesel or petrol, use white metal bearings. Diesels are universally copper-lead overlaid with a very thin film of lead-tin (occasionally lead - indium), while petrol engines use a variety of aluminium-based bearing metals, some with tin, some with lead, and other more exotic constructions. Also overlaid to improve embeddability and corrosion resistance.
rotrax
Well-known member
Thirty odd years ago BMW cars started the trend for service lights. The on board computer measured the milage done against the cold starts and tempretures reached.If you did a cold start and subsequently 50odd motorway miles ,this was good. Conversly,cold start and round the corner for your morning paper was bad. The computer tallied up its information and worked out when the engine required servicing with direct connection to its use-more cold starts,low tempreture runs=more frequent servicing. The same applies to our engine units. I am fortunate in that our engine will always reach operating tempreture by the time we hoist sails and turn it off when sailing from our home port-our mooring is far enough from the entrance and QHM requires exit under engine unless express permission is sought. Others who are not in this situation may wish to consider the potential increased wear if operating temp. is not reached most times the donk is used.
snowleopard
Active member
You can be too punctilious about oil changes. I sailed with one owner who, when motoring in a calm in mid-Atlantic, stopped the engine as the hour meter hit the specified number of hours. We rolled in the swell for a couple of hours while the engine cooled, changed the oil and started up again. Any sane person would have waited till the next port but not him. He also kept a couple of rolls in the genoa whatever the weather - in case the bolt rope pulled out of the groove. He also insisted on washing the stainless deck fittings with fresh water every day on passage, even when the watermaker broke down and water was rationed.
