How often do you change your oil

100 hours or so here; manual advises 200 hours.

Timely discussion as I am just about to change the 34 litres of oil in the Cat 3406. We do it once a year in May or June and the hours are 200 to 250. I fill to about 1/2 on the dipstick and it's about 1/4 when we change. Never needed to add any oil between changes.

However....I used to use Morris Ringfree 15w40 and never had any issues. Last year I changed to Agip (cheaper and easier to find) and now, after 200 hours there is a distinctly unpleasant odour from the breather filter which seems to permeate the boat - although I am the only one who has noticed it. It is only noticeable at low engine speeds when the fumes are not being sucked into the air intake filter adjacent to the breather filter. I don't believe there is excessive blowby as the simple test of loosening the filler cap doesn't show anything - nor can I feel any pressure.

So.. this year back to Morris oil - a bit more expensive but possibly worth it.

100 hours, approx.
Let me think:
$108.00 for oil, $12.00 for filters each change --
$18,000.00 + freight + installation for engines (each)
I agree with FF, oil is cheap.

Keith said:

100 hours or annually, whichever comes first .

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That would be my answer as well. I have a Volvo TAMD41P.

We are on a month long cruise and it looks like it will be about 140 hours before we get back home. I figure that won't hurt anything.

What's puzzling is that changing oil or any other routine maintenance based on engine hours doesn't really account for engine use.

For example, wouldn't 100 hours at 1500 RPM be about half the use and wear of 100 hours at 3000 RPM?

I'm in the 100 hr club. I just changed the oil on mine at 160 hrs and was surprised at the "thinness" of the used stuff. P.O. had used Delo which I've never used (Rotella guy). By the way Advanded Auto has Rotella for $13/gal right now! He also had a Fram on there Couldn't get that out fast enough for my comfort.

Twisted!
I use Delo 30 and 40W mixed together (35W ?)
Dos'nt seem thin to me.
I warm up slow and never have any trouble starting.

Why mix your own oils?? I usually make my cocktails with liquor!!

twiisted71 said:

.....By the way Advanded Auto has Rotella for $13/gal right now! .

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Walmart usually has it for $12 or a little less per gallon. Sometimes they have 2.5 gallon jugs at a slight savings over the single gallon price.

Chrisjs,
Simple.
Want oil thicker than 30W and thinner than 40W.
All real authorities I've ever read all agree that the higher the viscosity the oil the lower the wear.
I warm up to cruise speed in steps that take about 10 minutes.
Somehow I can't bring myself to run 40W in a nearly new engine.
And 30W is not very viscus when warm.
Personal preference.

manyboats said:

Chrisjs,
Simple.
Want oil thicker than 30W and thinner than 40W.
All real authorities I've ever read all agree that the higher the viscosity the oil the lower the wear.
I warm up to cruise speed in steps that take about 10 minutes.
Somehow I can't bring myself to run 40W in a nearly new engine.
And 30W is not very viscus when warm.
Personal preference.

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Why not just use a multi viscosity oil and be done with it?

Probably because multi-vis oil has additives and properties that can be less than desireable in some engines and some situations.

rwidman wrote:

"Why not just use a multi viscosity oil and be done with it?"

You do'nt get it. I do'nt run multi-vis oil because I do'nt need it.

I do'nt warm up my engine slowly because I need to.

I take 10 minutes to warm up anyway so why should I run oil that is less effective at lubricating so I can reduce my warm up time when I would'nt anyway.

manyboats said:

I warm up slow and never have any trouble starting.

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What warms up quicker, the oil or the water? The Coot's engine temperature gauge measures the water. Thermostat is set for 180-degree temperature. Start out at 1000 RPM (idle is 750) for a couple of minutes and then raise RPM to 1400 (low cruising speed) until engine water warms to about 160 degrees, then open her up a bit to 1600 or so until water temperature reaches maximum, and then up to between 1800 and 2200 RPM. Max RPM is 2400. Is this OK or is it abuse?

Depends on the engine. On our 1950s era engines it would be "abuse." On your engine it's probably a whole different deal, particularly if what you're doing is the procedure recommended by the manufacturer.

Marin said:

On your engine it's probably a whole different deal, particularly if what you're doing is the procedure recommended by the manufacturer.

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The engine's handbook is vague. (It emphasizes the need to avoid greater-than-a-five-minute idle time.) BUT, has the engine warmed up sufficiently to operate at normal engine speeds (two-thirds max load) by the time water temperature has reached maximum or is the engine still "warming up."

What's your warm-up procedure?

The coolant will warm up slower than the combustion chamber or cylinder temperatures. And those are the temperatures that are important to the engine, not so much the coolant.

While we have totally different engines than yours, we start ours when the boat is ready to go and after I've removed the spring lines. When the engines are going I turn on the electronics, select courses, radio channels, etc. So probably about 5-10 minutes worth of screwing around. Then we cast off the last two lines and go. Of course we're at idle until we clear the breakwater so that's another 5 minutes or so.

By then the port engine is pretty much up to coolant temp. The starboard engine lags way behind on the coolant temp because the coolant from that engine is routed to the hot water heater in the aft head which acts like a giant heat exchanger. It takes about 20 minutes at cruise rpm to get the coolant temperature of the starboard engine up the same as the port engine. However the exhaust gas temps of both engines track together from the outset.

We bring the power up in increments. Once clear of the breakwater I come up to 1200 rpm. No real reason for this number other than it's the rpm I use for initial approach in the Beaver so it's an rpm burned into my brain. After about 5-10 minutes at 1200 we bring them up to 1500. Five minutes or so at that rpm and we come on up to our cruise rpm of about 1650.

Coming in we reduce power to 1200 about five minutes out from the breakwater. As we come through the breakwater we drop back to a high idle of about 700 rpm. This give us just under 4 knots. As we approach our slip we come back to dead idle which is about 550 rpm.

rwidman
I'm with you. The multi-viz vs. straight-weight oil was debated endlessly by racers back in the '60s, and they all run multi-viz now.
I run 10-40w. My engines spin nicely when cold and have good oil pressure when hot, and that's what I care about.
Many viewpoints, many opinions. I've operated, overhauled, and maintained engines from 36 hp to 2375 hp for 38 years in helicopters, airplanes, race cars, and boats, but you have to sift through everything you read and make your own choice.

Regardless of how ancient the engine is, ideling stinks for warmup.

As soon as the engine runs stable a light load in gear is the kindest way to warm up for the first few min.

Dockside we start , take in the lines and just go.

If you look at a std engine /prop graph , you will see that at 1000 RPM or so almost no power is required to spin the prop, but it is better than 0 power of ideling.

Anchored it takes a min or two to fetch the anchor from the bottom with the hyd windlass.

manyboats said:

rwidman wrote:

"Why not just use a multi viscosity oil and be done with it?"

You do'nt get it. I do'nt run multi-vis oil because I do'nt need it.

I do'nt warm up my engine slowly because I need to.

I take 10 minutes to warm up anyway so why should I run oil that is less effective at lubricating so I can reduce my warm up time when I would'nt anyway.

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You are correct, I don't get it. I don't understand why you think you need some special oil that's unavailable commercially and I don't understand your last post.

The people who designed your engine know what oil is best for it. Follow their instructions.

What's your warm-up procedure?

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Once my electric is dsconnected and all but 2 lines I fire up, check for water out the exhaust, then go to the helm. First mate releases the last lines and I idle out of my slip and out into the Mystic River. Then it's 15 minutes of 800 to 1000 rpm down the river. Engine is above 140F by the time I can apply some power.

rwidman writes:
"I don't understand why you think you need some special oil"

I do'nt. The mixing is not required at all. I'm frequently an optimizer and I think 30W is just a tad too thin and 40W a tad too thick so I mix.

But the multi-vis is absolutely not needed in a trawler. As I've said before I use 10W30 and 20W50 in all my cars and trucks where they need to run on the road when cold at times is a given.

I do about the same as Marin. Open the seacock and start the engine. Run at 1000rpm while getting ready to leave. Back out and run out of the harbor at 1000rpm to 1400rpm as needed. Run awhile at 1400, then 1750, then 2000 and finally at 2300.....our normal cruise. By this time more than 10 minutes have passed. Notice Mark that at no time did I run at idle. But my idle is set high enough so that after one minute the engine will run maybe a bit rough but steady at an idle so I can maneuver the boat without danger of the engine quitting while maneuvering the boat out of the harbor.

With a good thermostat when your engine shows that it's at normal operating temperature much of the engine is still well below heat soaked. Much of the warm-up is still incomplete and I think working an engine at this point is not a good idea but w a diesel half load (or so (not rpm)) will be required to get the engine heat soaked. That's why it's not good to run most of the time at 30% load as the engine still is'nt warmed up.

The above is just my opinion and all or some may be incorrect. But I suspect that most real experts will agree.

Many viewpoints, many opinions. I've operated, overhauled, and maintained engines from 36 hp to 2375 hp for 38 years in helicopters, airplanes, race cars, and boats, but you have to sift through everything you read and make your own choice.

Old air cooled volkswagons? That's what I think of when I hear 36 hp!

Rob

Willy's engine is rated at 37hp.

And I never think of her as a VW. But had a 36hp VW in the late 60s.

I'm going to get a new Beetle when I get down to Washington. Very fast w turbo. Nowhere near 36hp I'm sure. More of a sports car.

I don't use bias-ply tires anymore, but I used to.
I don't use LORAN anymore, but I did.
I don't use VLF/OMEGA anymore, but it got me across the North Atlantic.
I don't use hemp rope, I'm not sure I ever did.
I still have flooded-cell batteries, but I like AGMs.
I still have a Bruce anchor, but I may switch to a R-----
I don't use straight-weight oil, but I used to.

Eric's point might be that while you have moved on to newer and better technologies the engines designed in the 50s and 60s haven't. They are just the same as when they were designed back in the straight-weight oil days. I was taught by one of the best aviation mechanics I've ever known to operate and maintain an engine in accordance with the way the people who designed and made it wanted it to be operated and maintained. So if it's a 1940s airplane radial, I operate it as though it was 1940. We operate and maintain the FL120s in our boat as though it was the 1950s when the engine was designed.

That's not to say that modern oils are detrimental (although some of them may be under some conditions) but that if the engine when operated in compiance with the 1950s operators manual went some 25,000 hours before needing an overhaul in commercial service and has a repuatation for going 12,000 to 14,000 hours in recreational service, I don't see a lot of reasons to deviate from the manual.

Maybe another way to approach this issue is to ask whether you can change oil too often (putting aside cost,inconvenience,and the planet)? The answer is likely to be negative.
There is every reason to follow the manufacturer`s recommendation on oil and change frequency,tempered by a little commonsense on how you use your boat, using the best quality recommended oil you can afford. BruceK

I totally agree with sticking with the manual...

For first aid aboard my boat I have my great grandfather's Civil War Field Surgeon's handbook...so every time I open my first aid kit...I refer to the manual first.

BruceK said:

Maybe another way to approach this issue is to ask whether you can change oil too often (putting aside cost,inconvenience,and the planet)? The answer is likely to be negative.
There is every reason to follow the manufacturer`s recommendation on oil and change frequency,tempered by a little commonsense on how you use your boat, using the best quality recommended oil you can afford. BruceK

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Flat out...no you can't change your oil too much...why not just let a fresh flow in and let it drip out the bottom into a waste container....

The trouble with using the word "best" with oil..is there's no such thing...there's different opinions and formulations for every oil...all we can do is discuss what we have experienced, heard, read, etc...etc through the years.

The best thing these forums can do for us is point out things we never came across befre or for the newer members...hopefully rid the world of the thousands of old wives tales out there...

rwidman said:

Why not just use a multi viscosity oil and be done with it?

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I second that. I use Castrol 10-40w Magnatec Diesel, and it works fine. I change yearly, which is less than 100 hrs because we don't do as much as that, (unfortunately), and always new filter each time, and I don't have to add oil in between, so I reckon all is pretty well, and I don't see the point in doing oil testing.

Marin said:

So if it's a 1940s airplane radial, I operate it as though it was 1940.

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So you use straight mineral oil and 78 octane leaded gas in that 985?

Just for grins compare the viscosity vs temp specs for the straight mineral oil that the 985 was designed to use and the AW 100 + or AW 15W- 50 that PW now recommends/approves for all their radial engines.

It has been a couple of years but when I ran PW radials for a living I had no qualms or questions about using the newest oils and happily used 15W-50 when flying 985s out of MSO in the winter. If you can think of a worse condition to lube a radial than climbing out of that hole at -30 into -50 or -60 in the winter then doing the same at 100+ in the summer, let me know.

What oil does Kenmore use in their recip Beavers these days?

The old designers spec'd the best they had available. They would have spec'd what we have now if they had it then.